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UPGRADE 1970'S BIKES
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UPGRADE 1970'S BIKES
On Friday, October 5, 2012 7:40:26 PM UTC-4, datakoll wrote:
http://sheldonbrown.com/upgrade.html I was looking for the replacement pedals. NNNNNNNNNNNNNNNNNN NOTICE allllllthe way at the end there's a link to rider's with your interests in older bicycles |
UPGRADE 1970'S BIKES
On Friday, October 5, 2012 7:58:46 PM UTC-4, datakoll wrote:
On Friday, October 5, 2012 7:40:26 PM UTC-4, datakoll wrote: http://sheldonbrown.com/upgrade.html I was looking for the replacement pedals. NNNNNNNNNNNNNNNNNN NOTICE allllllthe way at the end there's a link to rider's with your interests in older bicycles Interesting article on Sheldon's page. I'm pretty happy with all of my old Miele steel frame bicycles. I have pedals and toe clips on all but one of them. The other has clipless road pedals. I'm one of those that found the clipless mtb pedals (Wellgo clones of Shimano) too hard to get into. I have no problems entering either the cip and straps pedals or the clipless road pedals. I think that the flipping up of the pedal prior to entering it is so ingrained in me that I do it with the mtb pedals too and that's what makes it so hard to enter them. Since I'm happy enough with all my road pedals I'm not about to spend money experimenting trying to find an mtb pedal that suits me. I can get into my road pedals with toe clips as fast and as easily as I can with my Look type clipless pedals but then need to snug up the straps which means that getting the same security with the toe clip pedals takes longer than it does with the clipless ones. Periodically I use my Matrix rim tubular tires (old school 7 spd Dura Ace Uniglide cassette hub and Campy Record front hub) just for the enjoyment of their lively feel. Cheers |
UPGRADE 1970'S BIKES
On Oct 6, 5:38*am, Sir Ridesalot wrote:
On Friday, October 5, 2012 7:58:46 PM UTC-4, datakoll wrote: On Friday, October 5, 2012 7:40:26 PM UTC-4, datakoll wrote: http://sheldonbrown.com/upgrade.html I was looking for the replacement pedals. NNNNNNNNNNNNNNNNNN NOTICE allllllthe way at the end there's a link to rider's with your interests in older bicycles Interesting article on Sheldon's page. Indeed, very interesting article! He seems to have disagreed with many of the modern design trends. I tend to agree with Sheldon. I'm pretty happy with all of my old Miele steel frame bicycles. I have pedals and toe clips on all but one of them. ... I can get into my road pedals with toe clips as fast and as easily as I can with my Look type clipless pedals but then need to snug up the straps which means that getting the same security with the toe clip pedals takes longer than it does with the clipless ones. I usually have my straps set at a sort of compromise length, loose enough to flip into very quickly, but tight enough to provide just a bit of security against foot slips. They're tight enough that I can bunny hop, which is good enough for me. - Frank Krygowski |
UPGRADE 1970'S BIKES
On Saturday, October 6, 2012 1:53:52 PM UTC-4, Frank Krygowski wrote:
On Oct 6, 5:38*am, Sir Ridesalot wrote: On Friday, October 5, 2012 7:58:46 PM UTC-4, datakoll wrote: On Friday, October 5, 2012 7:40:26 PM UTC-4, datakoll wrote: http://sheldonbrown.com/upgrade.html I was looking for the replacement pedals. NNNNNNNNNNNNNNNNNN NOTICE allllllthe way at the end there's a link to rider's with your interests in older bicycles Interesting article on Sheldon's page. Indeed, very interesting article! He seems to have disagreed with many of the modern design trends. I tend to agree with Sheldon. I'm pretty happy with all of my old Miele steel frame bicycles. I have pedals and toe clips on all but one of them. ... I can get into my road pedals with toe clips as fast and as easily as I can with my Look type clipless pedals but then need to snug up the straps which means that getting the same security with the toe clip pedals takes longer than it does with the clipless ones. I usually have my straps set at a sort of compromise length, loose enough to flip into very quickly, but tight enough to provide just a bit of security against foot slips. They're tight enough that I can bunny hop, which is good enough for me. - Frank Krygowski That's how I have my toe straps adjusted in city riding. I'm really glad that I found some cleats for my old Shimano N600 pedals as I really like those pedals. I was really lucky to be able to get four of those cleats. I bought the second pair for a spare set. These cleats are interesting in that each cleat is composed of two interlocking pieces but comes with three parts per cleat. By changing the front section of the cleat you can assemble them for triangular type Shimano pedals or regular quill type pedals. Cheers |
UPGRADE 1970'S BIKES
Op zaterdag 6 oktober 2012 11:38:08 UTC+2 schreef Sir Ridesalot het volgende:
Interesting article on Sheldon's page. I'm pretty happy with all of my old Miele steel frame bicycles. I have pedals and toe clips on all but one of them. The other has clipless road pedals. I'm one of those that found the clipless mtb pedals (Wellgo clones of Shimano) too hard to get into. I have no problems entering either the cip and straps pedals or the clipless road pedals. I think that the flipping up of the pedal prior to entering it is so ingrained in me that I do it with the mtb pedals too and that's what makes it so hard to enter them. Since I'm happy enough with all my road pedals I'm not about to spend money experimenting trying to find an mtb pedal that suits me. I can get into my road pedals with toe clips as fast and as easily as I can with my Look type clipless pedals but then need to snug up the straps which means that getting the same security with the toe clip pedals takes longer than it does with the clipless ones. Periodically I use my Matrix rim tubular tires (old school 7 spd Dura Ace Uniglide cassette hub and Campy Record front hub) just for the enjoyment of their lively feel. Cheers There is no need to justify your choices and/or preferences Peter. Lou |
UPGRADE 1970'S BIKES
On Oct 6, 10:53*am, Frank Krygowski wrote:
On Oct 6, 5:38*am, Sir Ridesalot wrote: On Friday, October 5, 2012 7:58:46 PM UTC-4, datakoll wrote: On Friday, October 5, 2012 7:40:26 PM UTC-4, datakoll wrote: http://sheldonbrown.com/upgrade.html I was looking for the replacement pedals. NNNNNNNNNNNNNNNNNN NOTICE allllllthe way at the end there's a link to rider's with your interests in older bicycles Interesting article on Sheldon's page. Indeed, very interesting article! *He seems to have disagreed with many of the modern design trends. *I tend to agree with Sheldon. I'm pretty happy with all of my old Miele steel frame bicycles. I have pedals and toe clips on all but one of them. ... I can get into my road pedals with toe clips as fast and as easily as I can with my Look type clipless pedals but then need to snug up the straps which means that getting the same security with the toe clip pedals takes longer than it does with the clipless ones. I usually have my straps set at a sort of compromise length, loose enough to flip into very quickly, but tight enough to provide just a bit of security against foot slips. *They're tight enough that I can bunny hop, which is good enough for me. Based on all the trick riding I see, you don't need to be clipped in to bunny hop the bike -- but I find it hard to do on a road bike without clips, so I must be a flounder -- although the last time I rode on a platform with no clips, I was in an ortho-boot, so that may explain why I was having trouble bunny hopping. -- Jay Beattie. |
UPGRADE 1970'S BIKES
On Oct 6, 3:01*pm, Jay Beattie wrote:
On Oct 6, 10:53*am, Frank Krygowski wrote: I usually have my straps set at a sort of compromise length, loose enough to flip into very quickly, but tight enough to provide just a bit of security against foot slips. *They're tight enough that I can bunny hop, which is good enough for me. Based on all the trick riding I see, you don't need to be clipped in to bunny hop the bike -- but I find it hard to do on a road bike without clips, so I must be a flounder... I just tried it, to be sure of my memory. As I thought, I can get the rear wheel up just a little, maybe a couple inches, on a bike without clips. That's my retro 3 speed. I seem to be pushing a bit rearward on the pedals to do it, which seems to be the same thing I see in videos like http://www.youtube.com/watch?v=Z19zFlPah-o although there's obviously a lot more going on with someone at that skill level. For example, he temporarily repeals the law of gravity... - Frank Krygowski |
UPGRADE 1970'S BIKES
On Oct 6, 2:59*pm, Lou Holtman wrote:
Op zaterdag 6 oktober 2012 11:38:08 UTC+2 schreef Sir Ridesalot het volgende: Interesting article on Sheldon's page. I'm pretty happy with all of my old Miele steel frame bicycles. I have pedals and toe clips on all but one of them. The other has clipless road pedals. I'm one of those that found the clipless mtb pedals (Wellgo clones of Shimano) too hard to get into. I have no problems entering either the cip and straps pedals or the clipless road pedals. I think that the flipping up of the pedal prior to entering it is so ingrained in me that I do it with the mtb pedals too and that's what makes it so hard to enter them. Since I'm happy enough with all my road pedals I'm not about to spend money experimenting trying to find an mtb pedal that suits me. I can get into my road pedals with toe clips as fast and as easily as I can with my Look type clipless pedals but then need to snug up the straps which means that getting the same security with the toe clip pedals takes longer than it does with the clipless ones. Periodically I use my Matrix rim tubular tires (old school 7 spd Dura Ace Uniglide cassette hub and Campy Record front hub) just for the enjoyment of their lively feel. Cheers There is no need to justify your choices and/or preferences Peter. True. In fact, any discussions at all are entirely optional. One can always just ride bikes and never mention them to others. - Frank Krygowski |
UPGRADE 1970'S BIKES
educational...tho I carried a similar opinion of TdF frame sales, the roots were unknown.
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UPGRADE 1970'S BIKES
On Oct 6, 4:09 pm, Frank Krygowski wrote:
On Oct 6, 3:01 pm, Jay Beattie wrote: On Oct 6, 10:53 am, Frank Krygowski wrote: I usually have my straps set at a sort of compromise length, loose enough to flip into very quickly, but tight enough to provide just a bit of security against foot slips. They're tight enough that I can bunny hop, which is good enough for me. Based on all the trick riding I see, you don't need to be clipped in to bunny hop the bike -- but I find it hard to do on a road bike without clips, so I must be a flounder... I just tried it, to be sure of my memory. As I thought, I can get the rear wheel up just a little, maybe a couple inches, on a bike without clips. That's my retro 3 speed. I seem to be pushing a bit rearward on the pedals to do it, which seems to be the same thing I see in videos likehttp://www.youtube.com/watch?v=Z19zFlPah-o Look at ~2:00. See how his weight goes way back to lift the front end, then, springing off the pedals, he leaps into the air, chasing the front end with his body mass, until the handlebars are in his lap. The rear wheel is still on the ground. Then he fluidly but instantaneously transfers his body's inertia to the bike via the handlebars. See how his elbows and knees - fully extended a fraction of a second before - are bent at the top and the bike has come up underneath him? There's no lifting it by the pedals. I don't know if I've really got it figured out, but for me I think it's almost all through the handlebars. ... although there's obviously a lot more going on with someone at that skill level. For example, he temporarily repeals the law of gravity... Nice to see you embracing the inexplicable, but as we know (despite whatever the preacher sells you on Sunday), nature and physics do not ever take a break. If you ask him how he does it, he might say, "Ride Bike!" If you had asked Jimi Hendrix how he plays the guitar... |
UPGRADE 1970'S BIKES
Dan O writes:
On Oct 6, 4:09 pm, Frank Krygowski wrote: On Oct 6, 3:01 pm, Jay Beattie wrote: On Oct 6, 10:53 am, Frank Krygowski wrote: I usually have my straps set at a sort of compromise length, loose enough to flip into very quickly, but tight enough to provide just a bit of security against foot slips. They're tight enough that I can bunny hop, which is good enough for me. Based on all the trick riding I see, you don't need to be clipped in to bunny hop the bike -- but I find it hard to do on a road bike without clips, so I must be a flounder... I just tried it, to be sure of my memory. As I thought, I can get the rear wheel up just a little, maybe a couple inches, on a bike without clips. That's my retro 3 speed. I seem to be pushing a bit rearward on the pedals to do it, which seems to be the same thing I see in videos likehttp://www.youtube.com/watch?v=Z19zFlPah-o Look at ~2:00. See how his weight goes way back to lift the front end, then, springing off the pedals, he leaps into the air, chasing the front end with his body mass, until the handlebars are in his lap. The rear wheel is still on the ground. Then he fluidly but instantaneously transfers his body's inertia to the bike via the handlebars. See how his elbows and knees - fully extended a fraction of a second before - are bent at the top and the bike has come up underneath him? There's no lifting it by the pedals. I don't know if I've really got it figured out, but for me I think it's almost all through the handlebars. An impulsive force applied to the handlebars and in a direction directly away from the center of mass of the bike will do the trick. To verify that, stand in front of the bike and apply such an impulse; both wheels will leave the ground simultaneously. Alas, applying the same impulsive force while riding the bike is quite awkward (try it, you'll see). The way I believe it is done is in two steps: an upward pull, then a forward push. Those can be efficiently applied and since the average direction of the two force is through the CoM the result is nearly the same. -- Joe Riel |
UPGRADE 1970'S BIKES
there's a cable attached to the rider....
kinda lika jack knife dive into water. one would believe lifting with feet/abdomen transfering that motion to the bars thru shoulders is a complete body motion. its easy to do...getting effective height and control is difficult. |
UPGRADE 1970'S BIKES
On Oct 6, 10:59 pm, Joe Riel wrote:
Dan O writes: On Oct 6, 4:09 pm, Frank Krygowski wrote: On Oct 6, 3:01 pm, Jay Beattie wrote: On Oct 6, 10:53 am, Frank Krygowski wrote: I usually have my straps set at a sort of compromise length, loose enough to flip into very quickly, but tight enough to provide just a bit of security against foot slips. They're tight enough that I can bunny hop, which is good enough for me. Based on all the trick riding I see, you don't need to be clipped in to bunny hop the bike -- but I find it hard to do on a road bike without clips, so I must be a flounder... I just tried it, to be sure of my memory. As I thought, I can get the rear wheel up just a little, maybe a couple inches, on a bike without clips. That's my retro 3 speed. I seem to be pushing a bit rearward on the pedals to do it, which seems to be the same thing I see in videos likehttp://www.youtube.com/watch?v=Z19zFlPah-o Look at ~2:00. See how his weight goes way back to lift the front end, then, springing off the pedals, he leaps into the air, chasing the front end with his body mass, until the handlebars are in his lap. The rear wheel is still on the ground. Then he fluidly but instantaneously transfers his body's inertia to the bike via the handlebars. See how his elbows and knees - fully extended a fraction of a second before - are bent at the top and the bike has come up underneath him? There's no lifting it by the pedals. I don't know if I've really got it figured out, but for me I think it's almost all through the handlebars. An impulsive force applied to the handlebars and in a direction directly away from the center of mass of the bike will do the trick. To verify that, stand in front of the bike and apply such an impulse; both wheels will leave the ground simultaneously. Alas, applying the same impulsive force while riding the bike is quite awkward (try it, you'll see). The way I believe it is done is in two steps: an upward pull, then a forward push. Those can be efficiently applied and since the average direction of the two force is through the CoM the result is nearly the same. Right, note in the video how when Danny lifts the whole bike into the air at once his arms usually end up extended. I think it involves lifting the front end and launching yourself up right behind it, then thrusting the bars forward, rotating the bike in space underneath him, bringing the rear wheel up along with the front - the relative inertia of his upward flying body mass to maintain the front end off the ground - viola! - both wheels off the ground. It kind of cracks me up that Frank keeps his straps loose for virtually no backward retention, thinks the retention is where he applies force to bunnyhop, then thinks the force he applies is backward at the pedal. |
UPGRADE 1970'S BIKES
On Oct 7, 1:59*am, Joe Riel wrote:
Dan O writes: On Oct 6, 4:09 pm, Frank Krygowski wrote: On Oct 6, 3:01 pm, Jay Beattie wrote: On Oct 6, 10:53 am, Frank Krygowski wrote: I usually have my straps set at a sort of compromise length, loose enough to flip into very quickly, but tight enough to provide just a bit of security against foot slips. *They're tight enough that I can bunny hop, which is good enough for me. Based on all the trick riding I see, you don't need to be clipped in to bunny hop the bike -- but I find it hard to do on a road bike without clips, so I must be a flounder... I just tried it, to be sure of my memory. *As I thought, I can get the rear wheel up just a little, maybe a couple inches, on a bike without clips. *That's my retro 3 speed. *I seem to be pushing a bit rearward on the pedals to do it, which seems to be the same thing I see in videos likehttp://www.youtube.com/watch?v=Z19zFlPah-o Look at ~2:00. See how his weight goes way back to lift the front end, then, springing off the pedals, he leaps into the air, chasing the front end with his body mass, until the handlebars are in his lap. The rear wheel is still on the ground. *Then he fluidly but instantaneously transfers his body's inertia to the bike via the handlebars. *See how his elbows and knees - fully extended a fraction of a second before - are bent at the top and the bike has come up underneath him? *There's no lifting it by the pedals. I don't know if I've really got it figured out, but for me I think it's almost all through the handlebars. An impulsive force applied to the handlebars and in a direction directly away from the center of mass of the bike will do the trick. *To verify that, stand in front of the bike and apply such an impulse; both wheels will leave the ground simultaneously. *Alas, applying the same impulsive force while riding the bike is quite awkward (try it, you'll see). *The way I believe it is done is in two steps: an upward pull, then a forward push. *Those can be efficiently applied and since the average direction of the two force is through the CoM the result is nearly the same. That sounds like a possibility to me. However, when I do it on a flat pedal bike, I certainly get the impression my feet are pushing a bit backward on the pedals, and sort of trying to claw them upward, with my toes pointed downward. I'm trying to understand that sensation. (In the videos, it looks like the rider's toes are pointed down, too.) I'll get more serious than I was a couple posts ago (since nobody really repeals the law of gravity): To understand a bike being bunny hopped, I think it may help to think about how a skateboard is bunny hopped. The processes aren't the same (there's obviously no direct upward pull from the shoes on the skateboard) but I think there are some similarities. As I understand it, the skater jumps his own body mass upward. That's easy. And he'll soon lift his legs upward after his main body mass. But (nearly) simultaneously with the initial jump, he kicks down on the tail of the board. That levers the rest of the board upward, pivoting on the rear wheels. The board's center of mass is rising, so it's got upward inertia. It's also got rotational inertia, i.e. it's starting to do a backwards somersault. But a split second later, the skater's up-in-the-air foot applies downward force at the front half of the board to level it and stop that backwards rotation. So in that way, a pair of downward forces can produce upward motion of the board. So how much of this applies to jumping a flat pedaled bike? Certainly, the mass of the rider moves upward. But unlike the skateboard, he certainly applies a direct upward pull on the handlebars as his own body mass rises. That's easy to feel, and easy to see in the videos. But so far, all that's got us is a wheelie. Does the rider then push either forward on the bars (as Joe says) or downward on the bars (corresponding to the finish of the skateboard trick)? Seems either might work. And what, if anything, happens with the feet? It's raining pretty hard here right now, or I'd go out and play around trying to feel what I'm doing. But again, I'm hampered by simple lack of skill. I have to sense the forces during the brief duration of my tiny flat pedal bunny hop. Maybe someone more skilled can use their longer air time to analyze this? - Frank Krygowski |
UPGRADE 1970'S BIKES
On Oct 7, 11:14*am, Dan O wrote:
It kind of cracks me up that Frank keeps his straps loose for virtually no backward retention, thinks the retention is where he applies force to bunnyhop, then thinks the force he applies is backward at the pedal. I believe the foot technique is much different with my clips-and- straps pedals, compared to my flat pedals. Certainly, the height I can get is much different. I just posted speculation about how a flat pedal bunny hop is done, which is not saying I understand it completely. As I said, with flat pedals I get the sensation of clawing upward and backward with my toes- pointed-downward feet. Maybe that's an illusion, I don't know. But when I do a hop with clips and straps, that "backward" sensation is absent, and my toes don't point down at all. What I feel is much simpler: I jump my body upward, then I pull the bike upward after myself, exerting upward force on the bars (with my hands) and the pedal straps (with my feet). I've done that so many hundreds of times for so many years, with anything from an empty bike to a commuting bike with variously loaded briefcases, that I'd be astonished at proof that I'm not pulling directly upward on those straps. - Frank Krygowski |
UPGRADE 1970'S BIKES
On 10/7/2012 2:34 PM, Frank Krygowski wrote:
On Oct 7, 11:14 am, Dan O wrote: It kind of cracks me up that Frank keeps his straps loose for virtually no backward retention, thinks the retention is where he applies force to bunnyhop, then thinks the force he applies is backward at the pedal. I believe the foot technique is much different with my clips-and- straps pedals, compared to my flat pedals. Certainly, the height I can get is much different. I just posted speculation about how a flat pedal bunny hop is done, which is not saying I understand it completely. As I said, with flat pedals I get the sensation of clawing upward and backward with my toes- pointed-downward feet. Maybe that's an illusion, I don't know. But when I do a hop with clips and straps, that "backward" sensation is absent, and my toes don't point down at all. What I feel is much simpler: I jump my body upward, then I pull the bike upward after myself, exerting upward force on the bars (with my hands) and the pedal straps (with my feet). I've done that so many hundreds of times for so many years, with anything from an empty bike to a commuting bike with variously loaded briefcases, that I'd be astonished at proof that I'm not pulling directly upward on those straps. - Frank Krygowski https://www.youtube.com/results?sear....1.Zb5U9aCBNPE or http://preview.tinyurl.com/99p39s2 -- Andrew Muzi www.yellowjersey.org/ Open every day since 1 April, 1971 |
UPGRADE 1970'S BIKES
Frank Krygowski writes:
On Oct 7, 1:59Â*am, Joe Riel wrote: Dan O writes: On Oct 6, 4:09 pm, Frank Krygowski wrote: On Oct 6, 3:01 pm, Jay Beattie wrote: On Oct 6, 10:53 am, Frank Krygowski wrote: I usually have my straps set at a sort of compromise length, loose enough to flip into very quickly, but tight enough to provide just a bit of security against foot slips. Â*They're tight enough that I can bunny hop, which is good enough for me. Based on all the trick riding I see, you don't need to be clipped in to bunny hop the bike -- but I find it hard to do on a road bike without clips, so I must be a flounder... I just tried it, to be sure of my memory. Â*As I thought, I can get the rear wheel up just a little, maybe a couple inches, on a bike without clips. Â*That's my retro 3 speed. Â*I seem to be pushing a bit rearward on the pedals to do it, which seems to be the same thing I see in videos likehttp://www.youtube.com/watch?v=Z19zFlPah-o Look at ~2:00. See how his weight goes way back to lift the front end, then, springing off the pedals, he leaps into the air, chasing the front end with his body mass, until the handlebars are in his lap. The rear wheel is still on the ground. Â*Then he fluidly but instantaneously transfers his body's inertia to the bike via the handlebars. Â*See how his elbows and knees - fully extended a fraction of a second before - are bent at the top and the bike has come up underneath him? Â*There's no lifting it by the pedals. I don't know if I've really got it figured out, but for me I think it's almost all through the handlebars. An impulsive force applied to the handlebars and in a direction directly away from the center of mass of the bike will do the trick. Â*To verify that, stand in front of the bike and apply such an impulse; both wheels will leave the ground simultaneously. Â*Alas, applying the same impulsive force while riding the bike is quite awkward (try it, you'll see). Â*The way I believe it is done is in two steps: an upward pull, then a forward push. Â*Those can be efficiently applied and since the average direction of the two force is through the CoM the result is nearly the same. That sounds like a possibility to me. However, when I do it on a flat pedal bike, I certainly get the impression my feet are pushing a bit backward on the pedals, and sort of trying to claw them upward, with my toes pointed downward. I'm trying to understand that sensation. (In the videos, it looks like the rider's toes are pointed down, too.) I'll get more serious than I was a couple posts ago (since nobody really repeals the law of gravity): To understand a bike being bunny hopped, I think it may help to think about how a skateboard is bunny hopped. The processes aren't the same (there's obviously no direct upward pull from the shoes on the skateboard) but I think there are some similarities. As I understand it, the skater jumps his own body mass upward. That's easy. And he'll soon lift his legs upward after his main body mass. But (nearly) simultaneously with the initial jump, he kicks down on the tail of the board. That levers the rest of the board upward, pivoting on the rear wheels. The board's center of mass is rising, so it's got upward inertia. It's also got rotational inertia, i.e. it's starting to do a backwards somersault. But a split second later, the skater's up-in-the-air foot applies downward force at the front half of the board to level it and stop that backwards rotation. So in that way, a pair of downward forces can produce upward motion of the board. So how much of this applies to jumping a flat pedaled bike? Certainly, the mass of the rider moves upward. But unlike the skateboard, he certainly applies a direct upward pull on the handlebars as his own body mass rises. That's easy to feel, and easy to see in the videos. But so far, all that's got us is a wheelie. Does the rider then push either forward on the bars (as Joe says) or downward on the bars (corresponding to the finish of the skateboard trick)? Seems either might work. And what, if anything, happens with the feet? It's raining pretty hard here right now, or I'd go out and play around trying to feel what I'm doing. But again, I'm hampered by simple lack of skill. I have to sense the forces during the brief duration of my tiny flat pedal bunny hop. Maybe someone more skilled can use their longer air time to analyze this? - Frank Krygowski Something I did a dozen years or so ago was to stand on two low sawhorses, one on each side of the bike, and from there test stategies for yanking on the bars. That made experimenting easy. Doing so showed me that it really wasn't practical to get the rear wheels off the ground with a uni-direction yank; our body really isn't designed to do that in the required direction. Nor was was yanking while applying a torque to the bars (something I'd heard) feasible, at least not for me. What did work was the lift and push. I won't be attempting bunny hops any time soon. A month ago the front wheel slid in a corner I've rounded a thousand times (downhill, slightly offcamber). Don't know what I did wrong; I always go around the corner aggressively, but assumed I had a reasonable safety margin. Apparently the margin was exceeded. Cleanly broke the trochanter. Now I'm sporting a 10 inch rod in the femur with a four inch screw through trochanter. Have been walking with a cane for about two weeks now (that's better than using a walker). Need to do something for an aerobic workout, probably will be using the rowing machine for a awhile, though could try the turbo-trainer. -- Joe Riel |
UPGRADE 1970'S BIKES
bummmer...the greater or lesser trochanter ? yawl losing bone mass ?
did you try spinning thru getting off into the part 2 hop from bottom spin ? the Utubers are terrific,,,fluid. |
UPGRADE 1970'S BIKES
On Sunday, October 7, 2012 4:17:00 PM UTC-4, AMuzi wrote:
On 10/7/2012 2:34 PM, Frank Krygowski wrote: On Oct 7, 11:14 am, Dan O wrote: It kind of cracks me up that Frank keeps his straps loose for virtually no backward retention, thinks the retention is where he applies force to bunnyhop, then thinks the force he applies is backward at the pedal. I believe the foot technique is much different with my clips-and- straps pedals, compared to my flat pedals. Certainly, the height I can get is much different. I just posted speculation about how a flat pedal bunny hop is done, which is not saying I understand it completely. As I said, with flat pedals I get the sensation of clawing upward and backward with my toes- pointed-downward feet. Maybe that's an illusion, I don't know. But when I do a hop with clips and straps, that "backward" sensation is absent, and my toes don't point down at all. What I feel is much simpler: I jump my body upward, then I pull the bike upward after myself, exerting upward force on the bars (with my hands) and the pedal straps (with my feet). I've done that so many hundreds of times for so many years, with anything from an empty bike to a commuting bike with variously loaded briefcases, that I'd be astonished at proof that I'm not pulling directly upward on those straps. - Frank Krygowski https://www.youtube.com/results?sear....1.Zb5U9aCBNPE or http://preview.tinyurl.com/99p39s2 -- Andrew Muzi www.yellowjersey.org/ Open every day since 1 April, 1971 Sure looks like the front wheel comes off high first and then the rear wheel is raised by rotating the rear end up which is aided by the low air pressure in the tire. Cheers |
UPGRADE 1970'S BIKES
datakoll writes:
bummmer...the greater or lesser trochanter ? yawl losing bone mass ? Not sure, maybe both. That is, the break was in the thicker part of the bone that connects the main part of the femur to the head (which makes up the hip joint). I've got osteoporosis (a result of genetics, maybe cycling, and malabsorption due to a major resection of the small intestine), so was pretty sure something had broken after the crash. It didn't hurt, I just couldn't move the leg. -- Joe Riel |
UPGRADE 1970'S BIKES
On Oct 7, 2:15 pm, Joe Riel wrote:
Frank Krygowski writes: On Oct 7, 1:59 am, Joe Riel wrote: Dan O writes: On Oct 6, 4:09 pm, Frank Krygowski wrote: On Oct 6, 3:01 pm, Jay Beattie wrote: On Oct 6, 10:53 am, Frank Krygowski wrote: I usually have my straps set at a sort of compromise length, loose enough to flip into very quickly, but tight enough to provide just a bit of security against foot slips. They're tight enough that I can bunny hop, which is good enough for me. Based on all the trick riding I see, you don't need to be clipped in to bunny hop the bike -- but I find it hard to do on a road bike without clips, so I must be a flounder... I just tried it, to be sure of my memory. As I thought, I can get the rear wheel up just a little, maybe a couple inches, on a bike without clips. That's my retro 3 speed. I seem to be pushing a bit rearward on the pedals to do it, which seems to be the same thing I see in videos likehttp://www.youtube.com/watch?v=Z19zFlPah-o Look at ~2:00. See how his weight goes way back to lift the front end, then, springing off the pedals, he leaps into the air, chasing the front end with his body mass, until the handlebars are in his lap. The rear wheel is still on the ground. Then he fluidly but instantaneously transfers his body's inertia to the bike via the handlebars. See how his elbows and knees - fully extended a fraction of a second before - are bent at the top and the bike has come up underneath him? There's no lifting it by the pedals. I don't know if I've really got it figured out, but for me I think it's almost all through the handlebars. An impulsive force applied to the handlebars and in a direction directly away from the center of mass of the bike will do the trick. To verify that, stand in front of the bike and apply such an impulse; both wheels will leave the ground simultaneously. Alas, applying the same impulsive force while riding the bike is quite awkward (try it, you'll see). The way I believe it is done is in two steps: an upward pull, then a forward push. Those can be efficiently applied and since the average direction of the two force is through the CoM the result is nearly the same. That sounds like a possibility to me. However, when I do it on a flat pedal bike, I certainly get the impression my feet are pushing a bit backward on the pedals, and sort of trying to claw them upward, with my toes pointed downward. I'm trying to understand that sensation. (In the videos, it looks like the rider's toes are pointed down, too.) I'll get more serious than I was a couple posts ago (since nobody really repeals the law of gravity): To understand a bike being bunny hopped, I think it may help to think about how a skateboard is bunny hopped. The processes aren't the same (there's obviously no direct upward pull from the shoes on the skateboard) but I think there are some similarities. As I understand it, the skater jumps his own body mass upward. That's easy. And he'll soon lift his legs upward after his main body mass. But (nearly) simultaneously with the initial jump, he kicks down on the tail of the board. That levers the rest of the board upward, pivoting on the rear wheels. The board's center of mass is rising, so it's got upward inertia. It's also got rotational inertia, i.e. it's starting to do a backwards somersault. But a split second later, the skater's up-in-the-air foot applies downward force at the front half of the board to level it and stop that backwards rotation. So in that way, a pair of downward forces can produce upward motion of the board. So how much of this applies to jumping a flat pedaled bike? Certainly, the mass of the rider moves upward. But unlike the skateboard, he certainly applies a direct upward pull on the handlebars as his own body mass rises. That's easy to feel, and easy to see in the videos. But so far, all that's got us is a wheelie. Does the rider then push either forward on the bars (as Joe says) or downward on the bars (corresponding to the finish of the skateboard trick)? Seems either might work. And what, if anything, happens with the feet? It's raining pretty hard here right now, or I'd go out and play around trying to feel what I'm doing. But again, I'm hampered by simple lack of skill. I have to sense the forces during the brief duration of my tiny flat pedal bunny hop. Maybe someone more skilled can use their longer air time to analyze this? - Frank Krygowski Something I did a dozen years or so ago was to stand on two low sawhorses, one on each side of the bike, and from there test stategies for yanking on the bars. That made experimenting easy. Doing so showed me that it really wasn't practical to get the rear wheels off the ground with a uni-direction yank; our body really isn't designed to do that in the required direction. Nor was was yanking while applying a torque to the bars (something I'd heard) feasible, at least not for me. What did work was the lift and push. I just got on my bike and went out in the street Rode Bike! and *willed* the bike into the air. That's why I still sound uncertain when explaining it. That's why I get so incensed when Frank discounts what a rider "feels". "Those who can, do. Those who can't... " I won't be attempting bunny hops any time soon. A month ago the front wheel slid in a corner I've rounded a thousand times (downhill, slightly offcamber). Hate when that happens (losing the front end). Don't know what I did wrong; I always go around the corner aggressively, but assumed I had a reasonable safety margin. Apparently the margin was exceeded. I used to be a flattrack motorcycle racer, so sliding sideways is a fish in water kind of thing, and as a kid on a bicycle spent about as much time sideways as wheelying. If traction was iffy in a turn, I'd bust the rear tire loose, at which point you're steering with the rear wheel, and forces that would compromise front end traction vanish. I *relished* slick turns. As a longer distance bicycle rider now, I have become more hung up on things like conserving momentum, so ride more conventionally "road style", and consequently feel the fear of losing the front end, and don't push it when I suspect iffy traction. I've lost the front end a couple of times on the road in recent years (once on frezzing fog - idiot! - and once on a what I will presume was a petroleum spill adjacent to a gas station). Another time I was coming down a hill, making a fast turn on the paved shoulder (there are paint markings on this turn that I avoid having slipped on them), hit some sand or something and the front end started to go, but luckily I had sort of panic braked - both brakes - and broke the rear wheel loose. This was quite the thrilling moment - clipped into my SPuDs w/ both wheels sliding as I passed a pickup truck on the inside. But I do take it easy a lot more in my old age, and worried that I was losing my skill or something, but just rode over to the baseball diamond a little bit ago and pitched the wheelie bike sideways a couple times in the dry dirt - (barefoot), no brakes, no problem. When I was a kid I would throw just about any bike sideways any time even on dry pavement - wide handebars help - which was in fact my braking technique on one bike with freewheel and no brakes. Ah, invincible youth :-) Cleanly broke the trochanter. Now I'm sporting a 10 inch rod in the femur with a four inch screw through trochanter. Have been walking with a cane for about two weeks now (that's better than using a walker). Need to do something for an aerobic workout, probably will be using the rowing machine for a awhile, though could try the turbo-trainer. Ouch! Sending out positive waves for a full recovery. |
UPGRADE 1970'S BIKES
"Joe Riel" wrote in message ... Frank Krygowski writes: On Oct 7, 1:59 am, Joe Riel wrote: Dan O writes: On Oct 6, 4:09 pm, Frank Krygowski wrote: On Oct 6, 3:01 pm, Jay Beattie wrote: On Oct 6, 10:53 am, Frank Krygowski wrote: I usually have my straps set at a sort of compromise length, loose enough to flip into very quickly, but tight enough to provide just a bit of security against foot slips. They're tight enough that I can bunny hop, which is good enough for me. Based on all the trick riding I see, you don't need to be clipped in to bunny hop the bike -- but I find it hard to do on a road bike without clips, so I must be a flounder... I just tried it, to be sure of my memory. As I thought, I can get the rear wheel up just a little, maybe a couple inches, on a bike without clips. That's my retro 3 speed. I seem to be pushing a bit rearward on the pedals to do it, which seems to be the same thing I see in videos likehttp://www.youtube.com/watch?v=Z19zFlPah-o Look at ~2:00. See how his weight goes way back to lift the front end, then, springing off the pedals, he leaps into the air, chasing the front end with his body mass, until the handlebars are in his lap. The rear wheel is still on the ground. Then he fluidly but instantaneously transfers his body's inertia to the bike via the handlebars. See how his elbows and knees - fully extended a fraction of a second before - are bent at the top and the bike has come up underneath him? There's no lifting it by the pedals. I don't know if I've really got it figured out, but for me I think it's almost all through the handlebars. An impulsive force applied to the handlebars and in a direction directly away from the center of mass of the bike will do the trick. To verify that, stand in front of the bike and apply such an impulse; both wheels will leave the ground simultaneously. Alas, applying the same impulsive force while riding the bike is quite awkward (try it, you'll see). The way I believe it is done is in two steps: an upward pull, then a forward push. Those can be efficiently applied and since the average direction of the two force is through the CoM the result is nearly the same. That sounds like a possibility to me. However, when I do it on a flat pedal bike, I certainly get the impression my feet are pushing a bit backward on the pedals, and sort of trying to claw them upward, with my toes pointed downward. I'm trying to understand that sensation. (In the videos, it looks like the rider's toes are pointed down, too.) I'll get more serious than I was a couple posts ago (since nobody really repeals the law of gravity): To understand a bike being bunny hopped, I think it may help to think about how a skateboard is bunny hopped. The processes aren't the same (there's obviously no direct upward pull from the shoes on the skateboard) but I think there are some similarities. As I understand it, the skater jumps his own body mass upward. That's easy. And he'll soon lift his legs upward after his main body mass. But (nearly) simultaneously with the initial jump, he kicks down on the tail of the board. That levers the rest of the board upward, pivoting on the rear wheels. The board's center of mass is rising, so it's got upward inertia. It's also got rotational inertia, i.e. it's starting to do a backwards somersault. But a split second later, the skater's up-in-the-air foot applies downward force at the front half of the board to level it and stop that backwards rotation. So in that way, a pair of downward forces can produce upward motion of the board. So how much of this applies to jumping a flat pedaled bike? Certainly, the mass of the rider moves upward. But unlike the skateboard, he certainly applies a direct upward pull on the handlebars as his own body mass rises. That's easy to feel, and easy to see in the videos. But so far, all that's got us is a wheelie. Does the rider then push either forward on the bars (as Joe says) or downward on the bars (corresponding to the finish of the skateboard trick)? Seems either might work. And what, if anything, happens with the feet? It's raining pretty hard here right now, or I'd go out and play around trying to feel what I'm doing. But again, I'm hampered by simple lack of skill. I have to sense the forces during the brief duration of my tiny flat pedal bunny hop. Maybe someone more skilled can use their longer air time to analyze this? - Frank Krygowski Something I did a dozen years or so ago was to stand on two low sawhorses, one on each side of the bike, and from there test stategies for yanking on the bars. That made experimenting easy. Doing so showed me that it really wasn't practical to get the rear wheels off the ground with a uni-direction yank; our body really isn't designed to do that in the required direction. Nor was was yanking while applying a torque to the bars (something I'd heard) feasible, at least not for me. What did work was the lift and push. I won't be attempting bunny hops any time soon. A month ago the front wheel slid in a corner I've rounded a thousand times (downhill, slightly offcamber). Don't know what I did wrong; I always go around the corner aggressively, but assumed I had a reasonable safety margin. Apparently the margin was exceeded. Cleanly broke the trochanter. Now I'm sporting a 10 inch rod in the femur with a four inch screw through trochanter. Have been walking with a cane for about two weeks now (that's better than using a walker). Need to do something for an aerobic workout, probably will be using the rowing machine for a awhile, though could try the turbo-trainer. -- Joe Riel Joe Riel, Sorry to hear it. Hope you have a fast recovery, Kerry |
UPGRADE 1970'S BIKES
Not sure, maybe both. Your problem reinforces the Brandt Curve, where I should slow down another 5% |
UPGRADE 1970'S BIKES
On Oct 7, 2:15*pm, Joe Riel wrote:
Frank Krygowski writes: On Oct 7, 1:59*am, Joe Riel wrote: Dan O writes: On Oct 6, 4:09 pm, Frank Krygowski wrote: On Oct 6, 3:01 pm, Jay Beattie wrote: On Oct 6, 10:53 am, Frank Krygowski wrote: I usually have my straps set at a sort of compromise length, loose enough to flip into very quickly, but tight enough to provide just a bit of security against foot slips. *They're tight enough that I can bunny hop, which is good enough for me. Based on all the trick riding I see, you don't need to be clipped in to bunny hop the bike -- but I find it hard to do on a road bike without clips, so I must be a flounder... I just tried it, to be sure of my memory. *As I thought, I can get the rear wheel up just a little, maybe a couple inches, on a bike without clips. *That's my retro 3 speed. *I seem to be pushing a bit rearward on the pedals to do it, which seems to be the same thing I see in videos likehttp://www.youtube.com/watch?v=Z19zFlPah-o Look at ~2:00. See how his weight goes way back to lift the front end, then, springing off the pedals, he leaps into the air, chasing the front end with his body mass, until the handlebars are in his lap. The rear wheel is still on the ground. *Then he fluidly but instantaneously transfers his body's inertia to the bike via the handlebars. *See how his elbows and knees - fully extended a fraction of a second before - are bent at the top and the bike has come up underneath him? *There's no lifting it by the pedals. I don't know if I've really got it figured out, but for me I think it's almost all through the handlebars. An impulsive force applied to the handlebars and in a direction directly away from the center of mass of the bike will do the trick. *To verify that, stand in front of the bike and apply such an impulse; both wheels will leave the ground simultaneously. *Alas, applying the same impulsive force while riding the bike is quite awkward (try it, you'll see). *The way I believe it is done is in two steps: an upward pull, then a forward push. *Those can be efficiently applied and since the average direction of the two force is through the CoM the result is nearly the same. That sounds like a possibility to me. *However, when I do it on a flat pedal bike, I certainly get the impression my feet are pushing a bit backward on the pedals, and sort of trying to claw them upward, with my toes pointed downward. *I'm trying to understand that sensation. (In the videos, it looks like the rider's toes are pointed down, too.) I'll get more serious than I was a couple posts ago (since nobody really repeals the law of gravity): To understand a bike being bunny hopped, I think it may help to think about how a skateboard is bunny hopped. *The processes aren't the same (there's obviously no direct upward pull from the shoes on the skateboard) but I think there are some similarities. As I understand it, the skater jumps his own body mass upward. *That's easy. *And he'll soon lift his legs upward after his main body mass. But (nearly) simultaneously with the initial jump, he kicks down on the tail of the board. *That levers the rest of the board upward, pivoting on the rear wheels. *The board's center of mass is rising, so it's got upward inertia. *It's also got rotational inertia, i.e. it's starting to do a backwards somersault. *But a split second later, the skater's up-in-the-air foot applies downward force at the front half of the board to level it and stop that backwards rotation. *So in that way, a pair of downward forces can produce upward motion of the board. So how much of this applies to jumping a flat pedaled bike? Certainly, the mass of the rider moves upward. *But unlike the skateboard, he certainly applies a direct upward pull on the handlebars as his own body mass rises. *That's easy to feel, and easy to see in the videos. But so far, all that's got us is a wheelie. *Does the rider then push either forward on the bars (as Joe says) or downward on the bars (corresponding to the finish of the skateboard trick)? *Seems either might work. *And what, if anything, happens with the feet? It's raining pretty hard here right now, or I'd go out and play around trying to feel what I'm doing. *But again, I'm hampered by simple lack of skill. *I have to sense the forces during the brief duration of my tiny flat pedal bunny hop. *Maybe someone more skilled can use their longer air time to analyze this? - Frank Krygowski Something I did a dozen years or so ago was to stand on two low sawhorses, one on each side of the bike, and from there test stategies for yanking on the bars. *That made experimenting easy. *Doing so showed me that it really wasn't practical to get the rear wheels off the ground with a uni-direction yank; our body really isn't designed to do that in the required direction. *Nor was was yanking while applying a torque to the bars (something I'd heard) feasible, at least not for me. What did work was the lift and push. I won't be attempting bunny hops any time soon. *A month ago the front wheel slid in a corner I've rounded a thousand times (downhill, slightly offcamber). *Don't know what I did wrong; I always go around the corner aggressively, but assumed I had a reasonable safety margin. *Apparently the margin was exceeded. *Cleanly broke the trochanter. *Now I'm sporting a 10 inch rod in the femur with a four inch screw through trochanter. *Have been walking with a cane for about two weeks now (that's better than using a walker). *Need to do something for an aerobic workout, probably will be using the rowing machine for a awhile, though could try the turbo-trainer. Wow, do they place an IM rod for a trochanter or did you break the femur too? The amazing thing is being on a cane in a couple of weeks after surgery. -- Jay Beattie. |
UPGRADE 1970'S BIKES
On Oct 7, 6:22*pm, Dan O wrote:
On Oct 7, 2:15 pm, Joe Riel wrote: Frank Krygowski writes: On Oct 7, 1:59 am, Joe Riel wrote: Dan O writes: On Oct 6, 4:09 pm, Frank Krygowski wrote: On Oct 6, 3:01 pm, Jay Beattie wrote: On Oct 6, 10:53 am, Frank Krygowski wrote: I usually have my straps set at a sort of compromise length, loose enough to flip into very quickly, but tight enough to provide just a bit of security against foot slips. *They're tight enough that I can bunny hop, which is good enough for me. Based on all the trick riding I see, you don't need to be clipped in to bunny hop the bike -- but I find it hard to do on a road bike without clips, so I must be a flounder... I just tried it, to be sure of my memory. *As I thought, I can get the rear wheel up just a little, maybe a couple inches, on a bike without clips. *That's my retro 3 speed. *I seem to be pushing a bit rearward on the pedals to do it, which seems to be the same thing I see in videos likehttp://www.youtube.com/watch?v=Z19zFlPah-o Look at ~2:00. See how his weight goes way back to lift the front end, then, springing off the pedals, he leaps into the air, chasing the front end with his body mass, until the handlebars are in his lap. The rear wheel is still on the ground. *Then he fluidly but instantaneously transfers his body's inertia to the bike via the handlebars. *See how his elbows and knees - fully extended a fraction of a second before - are bent at the top and the bike has come up underneath him? *There's no lifting it by the pedals. I don't know if I've really got it figured out, but for me I think it's almost all through the handlebars. An impulsive force applied to the handlebars and in a direction directly away from the center of mass of the bike will do the trick. *To verify that, stand in front of the bike and apply such an impulse; both wheels will leave the ground simultaneously. *Alas, applying the same impulsive force while riding the bike is quite awkward (try it, you'll see). *The way I believe it is done is in two steps: an upward pull, then a forward push. *Those can be efficiently applied and since the average direction of the two force is through the CoM the result is nearly the same. That sounds like a possibility to me. *However, when I do it on a flat pedal bike, I certainly get the impression my feet are pushing a bit backward on the pedals, and sort of trying to claw them upward, with my toes pointed downward. *I'm trying to understand that sensation. (In the videos, it looks like the rider's toes are pointed down, too.) I'll get more serious than I was a couple posts ago (since nobody really repeals the law of gravity): To understand a bike being bunny hopped, I think it may help to think about how a skateboard is bunny hopped. *The processes aren't the same (there's obviously no direct upward pull from the shoes on the skateboard) but I think there are some similarities. As I understand it, the skater jumps his own body mass upward. *That's easy. *And he'll soon lift his legs upward after his main body mass.. But (nearly) simultaneously with the initial jump, he kicks down on the tail of the board. *That levers the rest of the board upward, pivoting on the rear wheels. *The board's center of mass is rising, so it's got upward inertia. *It's also got rotational inertia, i.e. it's starting to do a backwards somersault. *But a split second later, the skater's up-in-the-air foot applies downward force at the front half of the board to level it and stop that backwards rotation. *So in that way, a pair of downward forces can produce upward motion of the board.. So how much of this applies to jumping a flat pedaled bike? Certainly, the mass of the rider moves upward. *But unlike the skateboard, he certainly applies a direct upward pull on the handlebars as his own body mass rises. *That's easy to feel, and easy to see in the videos. But so far, all that's got us is a wheelie. *Does the rider then push either forward on the bars (as Joe says) or downward on the bars (corresponding to the finish of the skateboard trick)? *Seems either might work. *And what, if anything, happens with the feet? It's raining pretty hard here right now, or I'd go out and play around trying to feel what I'm doing. *But again, I'm hampered by simple lack of skill. *I have to sense the forces during the brief duration of my tiny flat pedal bunny hop. *Maybe someone more skilled can use their longer air time to analyze this? - Frank Krygowski Something I did a dozen years or so ago was to stand on two low sawhorses, one on each side of the bike, and from there test stategies for yanking on the bars. *That made experimenting easy. *Doing so showed me that it really wasn't practical to get the rear wheels off the ground with a uni-direction yank; our body really isn't designed to do that in the required direction. *Nor was was yanking while applying a torque to the bars (something I'd heard) feasible, at least not for me. What did work was the lift and push. I just got on my bike and went out in the street Rode Bike! and *willed* the bike into the air. *That's why I still sound uncertain when explaining it. *That's why I get so incensed when Frank discounts what a rider "feels". *"Those who can, do. *Those who can't... " I won't be attempting bunny hops any time soon. *A month ago the front wheel slid in a corner I've rounded a thousand times (downhill, slightly offcamber). Hate when that happens (losing the front end). Don't know what I did wrong; I always go around the corner aggressively, but assumed I had a reasonable safety margin. *Apparently the margin was exceeded. I used to be a flattrack motorcycle racer, so sliding sideways is a fish in water kind of thing, and as a kid on a bicycle spent about as much time sideways as wheelying. *If traction was iffy in a turn, I'd bust the rear tire loose, at which point you're steering with the rear wheel, and forces that would compromise front end traction vanish. *I *relished* slick turns. As a longer distance bicycle rider now, I have become more hung up on things like conserving momentum, so ride more conventionally "road style", and consequently feel the fear of losing the front end, and don't push it *when I suspect iffy traction. *I've lost the front end a couple of times on the road in recent years (once on frezzing fog - idiot! - and once on a what I will presume was a petroleum spill adjacent to a gas station). *Another time I was coming down a hill, making a fast turn on the paved shoulder (there are paint markings on this turn that I avoid having slipped on them), hit some sand or something and the front end started to go, but luckily I had sort of panic braked - both brakes - and broke the rear wheel loose. *This was quite the thrilling moment - clipped into my SPuDs w/ both wheels sliding as I passed a pickup truck on the inside. But I do take it easy a lot more in my old age, and worried that I was losing my skill or something, but just rode over to the baseball diamond a little bit ago and pitched the wheelie bike sideways a couple times in the dry dirt - (barefoot), no brakes, no problem. When I was a kid I would throw just about any bike sideways any time even on dry pavement - wide handebars help - which was in fact my braking technique on one bike with freewheel and no brakes. *Ah, invincible youth :-) Cleanly broke the trochanter. *Now I'm sporting a 10 inch rod in the femur with a four inch screw through trochanter. *Have been walking with a cane for about two weeks now (that's better than using a walker). *Need to do something for an aerobic workout, probably will be using the rowing machine for a awhile, though could try the turbo-trainer. Ouch! *Sending out positive waves for a full recovery. http://www.youtube.com/watch?feature...14GN2_zNE&NR=1 Most of us aren't that skilled or aren't ready for the total loss of front wheel traction. Jay Beattie |
UPGRADE 1970'S BIKES
On Oct 7, 7:18 pm, Jay Beattie wrote:
On Oct 7, 6:22 pm, Dan O wrote: [In which Dan brags of glory days and tries to convey a *touch* of what it is to Ride Bike to poor hapless Frank... ] http://www.youtube.com/watch?feature...14GN2_zNE&NR=1 Most of us aren't that skilled or aren't ready for the total loss of front wheel traction. "... total loss of front wheel traction." Hate when that happens. It's all over. BTDT. Know the feeling. Got the t-shirt. Bled on it. |
UPGRADE 1970'S BIKES
Jay Beattie writes:
On Oct 7, 2:15Â*pm, Joe Riel wrote: Frank Krygowski writes: On Oct 7, 1:59Â*am, Joe Riel wrote: Dan O writes: On Oct 6, 4:09 pm, Frank Krygowski wrote: On Oct 6, 3:01 pm, Jay Beattie wrote: On Oct 6, 10:53 am, Frank Krygowski wrote: I usually have my straps set at a sort of compromise length, loose enough to flip into very quickly, but tight enough to provide just a bit of security against foot slips. Â*They're tight enough that I can bunny hop, which is good enough for me. Based on all the trick riding I see, you don't need to be clipped in to bunny hop the bike -- but I find it hard to do on a road bike without clips, so I must be a flounder... I just tried it, to be sure of my memory. Â*As I thought, I can get the rear wheel up just a little, maybe a couple inches, on a bike without clips. Â*That's my retro 3 speed. Â*I seem to be pushing a bit rearward on the pedals to do it, which seems to be the same thing I see in videos likehttp://www.youtube.com/watch?v=Z19zFlPah-o Look at ~2:00. See how his weight goes way back to lift the front end, then, springing off the pedals, he leaps into the air, chasing the front end with his body mass, until the handlebars are in his lap. The rear wheel is still on the ground. Â*Then he fluidly but instantaneously transfers his body's inertia to the bike via the handlebars. Â*See how his elbows and knees - fully extended a fraction of a second before - are bent at the top and the bike has come up underneath him? Â*There's no lifting it by the pedals. I don't know if I've really got it figured out, but for me I think it's almost all through the handlebars. An impulsive force applied to the handlebars and in a direction directly away from the center of mass of the bike will do the trick. Â*To verify that, stand in front of the bike and apply such an impulse; both wheels will leave the ground simultaneously. Â*Alas, applying the same impulsive force while riding the bike is quite awkward (try it, you'll see). Â*The way I believe it is done is in two steps: an upward pull, then a forward push. Â*Those can be efficiently applied and since the average direction of the two force is through the CoM the result is nearly the same. That sounds like a possibility to me. Â*However, when I do it on a flat pedal bike, I certainly get the impression my feet are pushing a bit backward on the pedals, and sort of trying to claw them upward, with my toes pointed downward. Â*I'm trying to understand that sensation. (In the videos, it looks like the rider's toes are pointed down, too.) I'll get more serious than I was a couple posts ago (since nobody really repeals the law of gravity): To understand a bike being bunny hopped, I think it may help to think about how a skateboard is bunny hopped. Â*The processes aren't the same (there's obviously no direct upward pull from the shoes on the skateboard) but I think there are some similarities. As I understand it, the skater jumps his own body mass upward. Â*That's easy. Â*And he'll soon lift his legs upward after his main body mass. But (nearly) simultaneously with the initial jump, he kicks down on the tail of the board. Â*That levers the rest of the board upward, pivoting on the rear wheels. Â*The board's center of mass is rising, so it's got upward inertia. Â*It's also got rotational inertia, i.e. it's starting to do a backwards somersault. Â*But a split second later, the skater's up-in-the-air foot applies downward force at the front half of the board to level it and stop that backwards rotation. Â*So in that way, a pair of downward forces can produce upward motion of the board. So how much of this applies to jumping a flat pedaled bike? Certainly, the mass of the rider moves upward. Â*But unlike the skateboard, he certainly applies a direct upward pull on the handlebars as his own body mass rises. Â*That's easy to feel, and easy to see in the videos. But so far, all that's got us is a wheelie. Â*Does the rider then push either forward on the bars (as Joe says) or downward on the bars (corresponding to the finish of the skateboard trick)? Â*Seems either might work. Â*And what, if anything, happens with the feet? It's raining pretty hard here right now, or I'd go out and play around trying to feel what I'm doing. Â*But again, I'm hampered by simple lack of skill. Â*I have to sense the forces during the brief duration of my tiny flat pedal bunny hop. Â*Maybe someone more skilled can use their longer air time to analyze this? - Frank Krygowski Something I did a dozen years or so ago was to stand on two low sawhorses, one on each side of the bike, and from there test stategies for yanking on the bars. Â*That made experimenting easy. Â*Doing so showed me that it really wasn't practical to get the rear wheels off the ground with a uni-direction yank; our body really isn't designed to do that in the required direction. Â*Nor was was yanking while applying a torque to the bars (something I'd heard) feasible, at least not for me. What did work was the lift and push. I won't be attempting bunny hops any time soon. Â*A month ago the front wheel slid in a corner I've rounded a thousand times (downhill, slightly offcamber). Â*Don't know what I did wrong; I always go around the corner aggressively, but assumed I had a reasonable safety margin. Â*Apparently the margin was exceeded. Â*Cleanly broke the trochanter. Â*Now I'm sporting a 10 inch rod in the femur with a four inch screw through trochanter. Â*Have been walking with a cane for about two weeks now (that's better than using a walker). Â*Need to do something for an aerobic workout, probably will be using the rowing machine for a awhile, though could try the turbo-trainer. Wow, do they place an IM rod for a trochanter or did you break the femur too? The amazing thing is being on a cane in a couple of weeks after surgery. What's IM stand for? The main part of the femur didn't break. I'm pretty sure the rod in the femur is to support the screw/pin that goes through the trochanter (or whatever the part that connects to the ball joint is called). That screw is mechanically attached to the rod in the femur. There was also a secondary fracture of part of the trochanter that was left alone. From the X-rays I saw it seemed minor (i.e. not involved with support, etc). Yeah, my progress has been fairly quick, though am expecting a bit of a plateau soon enough. The acute rehab facility had me practice going up/down the fire-escape stairs using a cane less than a week after the crash; that was because I needed to learn to negotiate the stairs in my house which only have a handrail on one side. Stairs with handrails on both sides are trivial. Once home, I switched to a crutch for the stairs because it was more stable; used a walker otherwise. I can now walk without a cane, but it's not comfortable, too much compensation is required 'cause the glutes, etc, are too weak. With the cane, I can introduce a small torque that helps align the hips. -- Joe Riel |
UPGRADE 1970'S BIKES
On Oct 7, 9:43*pm, Joe Riel wrote:
Jay Beattie writes: On Oct 7, 2:15*pm, Joe Riel wrote: Frank Krygowski writes: On Oct 7, 1:59*am, Joe Riel wrote: Dan O writes: On Oct 6, 4:09 pm, Frank Krygowski wrote: On Oct 6, 3:01 pm, Jay Beattie wrote: On Oct 6, 10:53 am, Frank Krygowski wrote: I usually have my straps set at a sort of compromise length, loose enough to flip into very quickly, but tight enough to provide just a bit of security against foot slips. *They're tight enough that I can bunny hop, which is good enough for me. Based on all the trick riding I see, you don't need to be clipped in to bunny hop the bike -- but I find it hard to do on a road bike without clips, so I must be a flounder... I just tried it, to be sure of my memory. *As I thought, I can get the rear wheel up just a little, maybe a couple inches, on a bike without clips. *That's my retro 3 speed. *I seem to be pushing a bit rearward on the pedals to do it, which seems to be the same thing I see in videos likehttp://www.youtube.com/watch?v=Z19zFlPah-o Look at ~2:00. See how his weight goes way back to lift the front end, then, springing off the pedals, he leaps into the air, chasing the front end with his body mass, until the handlebars are in his lap.. The rear wheel is still on the ground. *Then he fluidly but instantaneously transfers his body's inertia to the bike via the handlebars. *See how his elbows and knees - fully extended a fraction of a second before - are bent at the top and the bike has come up underneath him? *There's no lifting it by the pedals. I don't know if I've really got it figured out, but for me I think it's almost all through the handlebars. An impulsive force applied to the handlebars and in a direction directly away from the center of mass of the bike will do the trick. *To verify that, stand in front of the bike and apply such an impulse; both wheels will leave the ground simultaneously. *Alas, applying the same impulsive force while riding the bike is quite awkward (try it, you'll see). *The way I believe it is done is in two steps: an upward pull, then a forward push. *Those can be efficiently applied and since the average direction of the two force is through the CoM the result is nearly the same. That sounds like a possibility to me. *However, when I do it on a flat pedal bike, I certainly get the impression my feet are pushing a bit backward on the pedals, and sort of trying to claw them upward, with my toes pointed downward. *I'm trying to understand that sensation.. (In the videos, it looks like the rider's toes are pointed down, too..) I'll get more serious than I was a couple posts ago (since nobody really repeals the law of gravity): To understand a bike being bunny hopped, I think it may help to think about how a skateboard is bunny hopped. *The processes aren't the same (there's obviously no direct upward pull from the shoes on the skateboard) but I think there are some similarities. As I understand it, the skater jumps his own body mass upward. *That's easy. *And he'll soon lift his legs upward after his main body mass. But (nearly) simultaneously with the initial jump, he kicks down on the tail of the board. *That levers the rest of the board upward, pivoting on the rear wheels. *The board's center of mass is rising, so it's got upward inertia. *It's also got rotational inertia, i.e. it's starting to do a backwards somersault. *But a split second later, the skater's up-in-the-air foot applies downward force at the front half of the board to level it and stop that backwards rotation. *So in that way, a pair of downward forces can produce upward motion of the board. So how much of this applies to jumping a flat pedaled bike? Certainly, the mass of the rider moves upward. *But unlike the skateboard, he certainly applies a direct upward pull on the handlebars as his own body mass rises. *That's easy to feel, and easy to see in the videos. But so far, all that's got us is a wheelie. *Does the rider then push either forward on the bars (as Joe says) or downward on the bars (corresponding to the finish of the skateboard trick)? *Seems either might work. *And what, if anything, happens with the feet? It's raining pretty hard here right now, or I'd go out and play around trying to feel what I'm doing. *But again, I'm hampered by simple lack of skill. *I have to sense the forces during the brief duration of my tiny flat pedal bunny hop. *Maybe someone more skilled can use their longer air time to analyze this? - Frank Krygowski Something I did a dozen years or so ago was to stand on two low sawhorses, one on each side of the bike, and from there test stategies for yanking on the bars. *That made experimenting easy. *Doing so showed me that it really wasn't practical to get the rear wheels off the ground with a uni-direction yank; our body really isn't designed to do that in the required direction. *Nor was was yanking while applying a torque to the bars (something I'd heard) feasible, at least not for me.. What did work was the lift and push. I won't be attempting bunny hops any time soon. *A month ago the front wheel slid in a corner I've rounded a thousand times (downhill, slightly offcamber). *Don't know what I did wrong; I always go around the corner aggressively, but assumed I had a reasonable safety margin. *Apparently the margin was exceeded. *Cleanly broke the trochanter. *Now I'm sporting a 10 inch rod in the femur with a four inch screw through trochanter. *Have been walking with a cane for about two weeks now (that's better than using a walker). *Need to do something for an aerobic workout, probably will be using the rowing machine for a awhile, though could try the turbo-trainer. Wow, do they place an IM rod for a trochanter or did you break the femur too? The amazing thing is being on a cane in a couple of weeks after surgery. What's IM stand for? *The main part of the femur didn't break. *I'm pretty sure the rod in the femur is to support the screw/pin that goes through the trochanter (or whatever the part that connects to the ball joint is called). *That screw is mechanically attached to the rod in the femur. *There was also a secondary fracture of part of the trochanter that was left alone. *From the X-rays I saw it seemed minor (i.e. not involved with support, etc). Yeah, my progress has been fairly quick, though am expecting a bit of a plateau soon enough. *The acute rehab facility had me practice going up/down the fire-escape stairs using a cane less than a week after the crash; that was because I needed to learn to negotiate the stairs in my house which only have a handrail on one side. *Stairs with handrails on both sides are trivial. *Once home, I switched to a crutch for the stairs because it was more stable; used a walker otherwise. I can now walk without a cane, but it's not comfortable, too much compensation is required 'cause the glutes, etc, are too weak. *With the cane, I can introduce a small torque that helps align the hips. IM stands for intermedullary -- within the marrow cavity of a bone. So they drill out the marrow cavity and drive in a rod or "nail," usually to stabilize a fracture, but in your case, it sounds like they used it as some sort of anchor for the the screw through the trochanter. People with leg fractures usually spend months on crutches, so you're doing great. Now you have to go back to the scene of the crime and figure out what happened. Sort of OT, but I was descending a familiar hill and slid out and crashed and broke a few ribs but no major bones. A week or so later I felt good enough to go riding, and while descending yet another hill, I developed a huge shimmy -- so bad, I had trouble steering he bike to a stop. This was on a bike that had never had a shimmy and on a hill I had ridden hundreds of times. It was all due to nerves. Apart from your physical rehab, it takes a little while to get over the psychological effect of crashing. I'm doing a lot of riding with a guy who was hit by a car in an intersection in spring, and apart from recovering from having his clavicle resected, he is nervous around cars now -- particularly at intersections. He has a tendency to jam on his brakes at odd moments, making drafting a little challenging. -- Jay Beattie. |
UPGRADE 1970'S BIKES
Jay Beattie writes:
On Oct 7, 9:43Â*pm, Joe Riel wrote: Jay Beattie writes: On Oct 7, 2:15Â*pm, Joe Riel wrote: Frank Krygowski writes: On Oct 7, 1:59Â*am, Joe Riel wrote: Dan O writes: On Oct 6, 4:09 pm, Frank Krygowski wrote: On Oct 6, 3:01 pm, Jay Beattie wrote: On Oct 6, 10:53 am, Frank Krygowski wrote: I usually have my straps set at a sort of compromise length, loose enough to flip into very quickly, but tight enough to provide just a bit of security against foot slips. Â*They're tight enough that I can bunny hop, which is good enough for me. Based on all the trick riding I see, you don't need to be clipped in to bunny hop the bike -- but I find it hard to do on a road bike without clips, so I must be a flounder... I just tried it, to be sure of my memory. Â*As I thought, I can get the rear wheel up just a little, maybe a couple inches, on a bike without clips. Â*That's my retro 3 speed. Â*I seem to be pushing a bit rearward on the pedals to do it, which seems to be the same thing I see in videos likehttp://www.youtube.com/watch?v=Z19zFlPah-o Look at ~2:00. See how his weight goes way back to lift the front end, then, springing off the pedals, he leaps into the air, chasing the front end with his body mass, until the handlebars are in his lap. The rear wheel is still on the ground. Â*Then he fluidly but instantaneously transfers his body's inertia to the bike via the handlebars. Â*See how his elbows and knees - fully extended a fraction of a second before - are bent at the top and the bike has come up underneath him? Â*There's no lifting it by the pedals. I don't know if I've really got it figured out, but for me I think it's almost all through the handlebars. An impulsive force applied to the handlebars and in a direction directly away from the center of mass of the bike will do the trick. Â*To verify that, stand in front of the bike and apply such an impulse; both wheels will leave the ground simultaneously. Â*Alas, applying the same impulsive force while riding the bike is quite awkward (try it, you'll see). Â*The way I believe it is done is in two steps: an upward pull, then a forward push. Â*Those can be efficiently applied and since the average direction of the two force is through the CoM the result is nearly the same. That sounds like a possibility to me. Â*However, when I do it on a flat pedal bike, I certainly get the impression my feet are pushing a bit backward on the pedals, and sort of trying to claw them upward, with my toes pointed downward. Â*I'm trying to understand that sensation. (In the videos, it looks like the rider's toes are pointed down, too.) I'll get more serious than I was a couple posts ago (since nobody really repeals the law of gravity): To understand a bike being bunny hopped, I think it may help to think about how a skateboard is bunny hopped. Â*The processes aren't the same (there's obviously no direct upward pull from the shoes on the skateboard) but I think there are some similarities. As I understand it, the skater jumps his own body mass upward. Â*That's easy. Â*And he'll soon lift his legs upward after his main body mass. But (nearly) simultaneously with the initial jump, he kicks down on the tail of the board. Â*That levers the rest of the board upward, pivoting on the rear wheels. Â*The board's center of mass is rising, so it's got upward inertia. Â*It's also got rotational inertia, i.e. it's starting to do a backwards somersault. Â*But a split second later, the skater's up-in-the-air foot applies downward force at the front half of the board to level it and stop that backwards rotation. Â*So in that way, a pair of downward forces can produce upward motion of the board. So how much of this applies to jumping a flat pedaled bike? Certainly, the mass of the rider moves upward. Â*But unlike the skateboard, he certainly applies a direct upward pull on the handlebars as his own body mass rises. Â*That's easy to feel, and easy to see in the videos. But so far, all that's got us is a wheelie. Â*Does the rider then push either forward on the bars (as Joe says) or downward on the bars (corresponding to the finish of the skateboard trick)? Â*Seems either might work. Â*And what, if anything, happens with the feet? It's raining pretty hard here right now, or I'd go out and play around trying to feel what I'm doing. Â*But again, I'm hampered by simple lack of skill. Â*I have to sense the forces during the brief duration of my tiny flat pedal bunny hop. Â*Maybe someone more skilled can use their longer air time to analyze this? - Frank Krygowski Something I did a dozen years or so ago was to stand on two low sawhorses, one on each side of the bike, and from there test stategies for yanking on the bars. Â*That made experimenting easy. Â*Doing so showed me that it really wasn't practical to get the rear wheels off the ground with a uni-direction yank; our body really isn't designed to do that in the required direction. Â*Nor was was yanking while applying a torque to the bars (something I'd heard) feasible, at least not for me. What did work was the lift and push. I won't be attempting bunny hops any time soon. Â*A month ago the front wheel slid in a corner I've rounded a thousand times (downhill, slightly offcamber). Â*Don't know what I did wrong; I always go around the corner aggressively, but assumed I had a reasonable safety margin. Â*Apparently the margin was exceeded. Â*Cleanly broke the trochanter. Â*Now I'm sporting a 10 inch rod in the femur with a four inch screw through trochanter. Â*Have been walking with a cane for about two weeks now (that's better than using a walker). Â*Need to do something for an aerobic workout, probably will be using the rowing machine for a awhile, though could try the turbo-trainer. Wow, do they place an IM rod for a trochanter or did you break the femur too? The amazing thing is being on a cane in a couple of weeks after surgery. What's IM stand for? Â*The main part of the femur didn't break. Â*I'm pretty sure the rod in the femur is to support the screw/pin that goes through the trochanter (or whatever the part that connects to the ball joint is called). Â*That screw is mechanically attached to the rod in the femur. Â*There was also a secondary fracture of part of the trochanter that was left alone. Â*From the X-rays I saw it seemed minor (i.e. not involved with support, etc). Yeah, my progress has been fairly quick, though am expecting a bit of a plateau soon enough. Â*The acute rehab facility had me practice going up/down the fire-escape stairs using a cane less than a week after the crash; that was because I needed to learn to negotiate the stairs in my house which only have a handrail on one side. Â*Stairs with handrails on both sides are trivial. Â*Once home, I switched to a crutch for the stairs because it was more stable; used a walker otherwise. I can now walk without a cane, but it's not comfortable, too much compensation is required 'cause the glutes, etc, are too weak. Â*With the cane, I can introduce a small torque that helps align the hips. IM stands for intermedullary -- within the marrow cavity of a bone. So they drill out the marrow cavity and drive in a rod or "nail," usually to stabilize a fracture, but in your case, it sounds like they used it as some sort of anchor for the the screw through the trochanter. People with leg fractures usually spend months on crutches, so you're doing great. Now you have to go back to the scene of the crime and figure out what happened. It was a block away from home---I was returning from a ride. I've walked by it several times recently and didn't learn anything. That day was hot (+95F), with high humidity. On the ride I felt sporadic rain drops, but never saw any moisture on the road and doubt that was an issue. A cyclist next door suggested that the heat could have softened the tar strip used to repair a crack in the road, however, that runs across the road, so I would have been crossing it (it's less than two inches wide)---seems unlikely to be a factor. My current hypothesis was rider error. I was riding the Moulton, and, while I've been around that corner on the Moulton many times, most were a few years ago when returning from a daily commute. Now most of my riding [and hard cornering] is done on a regular road bike, and the handling is significantly different; the Moulton responds much faster. I still haven't made a serious inspection of the Moulton---it appears to have just cosmetic damage to the right side bar tape where the bike slid. Sort of OT, but I was descending a familiar hill and slid out and crashed and broke a few ribs but no major bones. A week or so later I felt good enough to go riding, and while descending yet another hill, I developed a huge shimmy -- so bad, I had trouble steering he bike to a stop. This was on a bike that had never had a shimmy and on a hill I had ridden hundreds of times. It was all due to nerves. Apart from your physical rehab, it takes a little while to get over the psychological effect of crashing. I'm doing a lot of riding with a guy who was hit by a car in an intersection in spring, and apart from recovering from having his clavicle resected, he is nervous around cars now -- particularly at intersections. He has a tendency to jam on his brakes at odd moments, making drafting a little challenging. Yeah, that will be interesting, seeing how I deal with it. I was wondering what would have happened if I crashed further from home. That is, a woman in the neighborhood stopped, called 911, and later dropped my bike off at my house. What is the usual protocol when on the road? Would the paramedics bring the bike to the hospital? Seems unlikely, but leaving/losing it would have added insult to injury (I was riding alone). -- Joe Riel |
UPGRADE 1970'S BIKES
On Oct 7, 7:18*pm, Jay Beattie wrote:
On Oct 7, 6:22*pm, Dan O wrote: On Oct 7, 2:15 pm, Joe Riel wrote: Frank Krygowski writes: On Oct 7, 1:59 am, Joe Riel wrote: Dan O writes: On Oct 6, 4:09 pm, Frank Krygowski wrote: On Oct 6, 3:01 pm, Jay Beattie wrote: On Oct 6, 10:53 am, Frank Krygowski wrote: I usually have my straps set at a sort of compromise length, loose enough to flip into very quickly, but tight enough to provide just a bit of security against foot slips. *They're tight enough that I can bunny hop, which is good enough for me. Based on all the trick riding I see, you don't need to be clipped in to bunny hop the bike -- but I find it hard to do on a road bike without clips, so I must be a flounder... I just tried it, to be sure of my memory. *As I thought, I can get the rear wheel up just a little, maybe a couple inches, on a bike without clips. *That's my retro 3 speed. *I seem to be pushing a bit rearward on the pedals to do it, which seems to be the same thing I see in videos likehttp://www.youtube.com/watch?v=Z19zFlPah-o Look at ~2:00. See how his weight goes way back to lift the front end, then, springing off the pedals, he leaps into the air, chasing the front end with his body mass, until the handlebars are in his lap. The rear wheel is still on the ground. *Then he fluidly but instantaneously transfers his body's inertia to the bike via the handlebars. *See how his elbows and knees - fully extended a fraction of a second before - are bent at the top and the bike has come up underneath him? *There's no lifting it by the pedals. I don't know if I've really got it figured out, but for me I think it's almost all through the handlebars. An impulsive force applied to the handlebars and in a direction directly away from the center of mass of the bike will do the trick. *To verify that, stand in front of the bike and apply such an impulse; both wheels will leave the ground simultaneously. *Alas, applying the same impulsive force while riding the bike is quite awkward (try it, you'll see). *The way I believe it is done is in two steps: an upward pull, then a forward push. *Those can be efficiently applied and since the average direction of the two force is through the CoM the result is nearly the same. That sounds like a possibility to me. *However, when I do it on a flat pedal bike, I certainly get the impression my feet are pushing a bit backward on the pedals, and sort of trying to claw them upward, with my toes pointed downward. *I'm trying to understand that sensation. |
UPGRADE 1970'S BIKES
On Oct 7, 5:15*pm, Joe Riel wrote:
I won't be attempting bunny hops any time soon. *A month ago the front wheel slid in a corner I've rounded a thousand times (downhill, slightly offcamber). *Don't know what I did wrong; I always go around the corner aggressively, but assumed I had a reasonable safety margin. *Apparently the margin was exceeded. *Cleanly broke the trochanter. Wow. Sorry to hear it. - Frank Krygowski |
UPGRADE 1970'S BIKES
On Oct 7, 4:17*pm, AMuzi wrote:
On 10/7/2012 2:34 PM, Frank Krygowski wrote: https://www.youtube.com/results?sear...ny+hop+a+bicyc.... or http://preview.tinyurl.com/99p39s2 Ah, good! Looks to me like that verifies a lot of what Joe and I were saying. He pulls up on the bars. But he doesn't jump up at the beginning; instead, he gets his weight "as far back as you can," sort of kicking his center of mass downward and backwards with respect to the bike just before pulling the front wheel up. (That's a lot easier with a short wheelbase BMX bike and low saddle.) As the front wheel begins rising, he jumps his center of mass upward. You can see his legs straighten. Then comes the "scoop with your feet" that he mentions, the toes-down action I described that helps kick the rear of the bike upward. He also mentions a "J motion" of the hands, which corresponds to what Joe was saying. Oddly, he doesn't seem to mention that he "*willed* the bike into the air." Since he's trying to _teach_ people, maybe he thought such hocus-pocus language wasn't particularly helpful? - Frank Krygowski |
UPGRADE 1970'S BIKES
On Oct 8, 10:23*am, Jay Beattie wrote:
Sort of OT, but I was descending a familiar hill and slid out and crashed and broke a few ribs but no major bones. *A week or so later I felt good enough to go riding, and while descending yet another hill, I developed a huge shimmy -- so bad, I had trouble steering he bike to a stop. *This was on a bike that had never had a shimmy and on a hill I had ridden hundreds of times. *It was all due to nerves. That's really interesting. It seems very likely that a person's shaking or trembling from nervousness would be within range of a bike's resonant frequency for lateral vibration. Talk about a feedback loop! Nervousness inducing shimmy, shimmy inducing more nervousness... Apart from your physical rehab, it takes a little while to get over the psychological effect of crashing. *I'm doing a lot of riding with a guy who was hit by a car in an intersection in spring, and apart from recovering from having his clavicle resected, he is nervous around cars now -- particularly at intersections. *He has a tendency to jam on his brakes at odd moments, making drafting a little challenging. Fear can be terrible. One of my good friends experienced a near crash on a long, fast downhill. As he told it (I wasn't there), his front tire blew out but stayed on the rim. He panicked and locked up his rear, which also blew out. He skidded across the oncoming lane and stopped upright on the shoulder. No crash, but he never recovered psychologically. Afterwards he was unable to descend at more than about 10 mph; he was literally slower downhill than uphill. He gave up riding soon after. But that brings up another feedback loop. I recall from my mountain biking days that there were obstacles I'd try to "clean" (in the observed trials sense) that were impossible unless I committed to taking the risk of a fall. I think a more cautious person couldn't pull it off at all, and the failure to pull it off would lead to more nervousness. I can envision that phenomenon working in lots of different situations, everything from giving a speech to controlling a narrow lane. - Frank Krygowski |
UPGRADE 1970'S BIKES
On Oct 8, 10:18*am, Frank Krygowski wrote:
snip But that brings up another feedback loop. *I recall from my mountain biking days that there were obstacles I'd try to "clean" (in the observed trials sense) that were impossible unless I committed to taking the risk of a fall. And I find some things I try to do involve significant risk of falling out of bed ;-) *I think a more cautious person couldn't pull it off at all, and the failure to pull it off would lead to more nervousness. I can envision that phenomenon working in lots of different situations, everything from giving a speech to controlling a narrow lane. La vida loca! |
UPGRADE 1970'S BIKES
On Mon, 08 Oct 2012 08:34:12 -0700, Joe Riel wrote:
Would the paramedics bring the bike to the hospital? A deputy took my bike, after establishing that no other vehicle had been involved. My spouse retrieved it from the sheriff's sub-station, and was annoyed that they didn't ask for proof that he was my spouse. -- Joy Beeson joy beeson at comcast dot net |
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