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