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On Sat, 04 Sep 2004 03:34:01 GMT, Mark McMaster
wrote: wrote: On Thu, 2 Sep 2004 11:39:45 -0700, "Tom Nakashima" wrote: wrote in message ... On Thu, 2 Sep 2004 07:33:13 -0700, "Tom Nakashima" Yes, Mark, one who understands motorcycling. Here's another link on a motorcycle slide bike course that one can enroll in. http://www.motorcycle.com/mo/mccustom/slide.html -tom Dear Tom, The page seems to suggest only rear-wheel power slides exiting paved corners. The apparatus appears to be designed to prevent the motorcycle rider from falling down if he exceeds the limits of traction. Am I mistaken? Carl Fogel Yes Carl Fogel that is correct, the lean slide bike apparatus is to keep the rider from falling down, however it not only suggest power sliding the rear wheel, but the front wheel also slides as well. I actually spoke with a motorcycle rider (co-worker) this morning who took the Keith Code course here at SLAC, the rear tire, as well as the front tire does slide in the corners with the control of the throttle. The front not as much as the rear. He also said your gauge for your limits of slide and lean angle is your knee touching the ground. Did you also read about the paragraph about controlled slide? Are you convinced now? Maybe you should take the Keith Code course yourself if you're still not convinced. -tom Dear Tom, Well, no, to be frank, I'm not convinced that racers are cornering so hard on pavement that their front tires lose traction and slide. The word "slide" might be a bit imprecise. However, wide tires rolling under high lateral force do exhibit what is known as a slip angle, caused as the rubber deforms as it rolls through the contact patch. This action of the rubber "walking" or "squirming" laterally makes the wheel act as if slipping sideways as it rolled. http://www.msgroup.org/TIP076.html What path would a motorcycle or bicycle follow if the front tire began to slide sideways under hard cornering? On a motorcycle, riders describe the feeling as "understeer" or "oversteer" (depending on which tire is slipping more), causing the path of the motorcycle to turn at a greater or less radius, respectively, than the steering angle would indicate. The contact patch of a bicycle tire isn't large or wide enough to exhibit any significant slip angle. Under hard cornering, a bicycle either tracks exactly as the steering angle requires, or the tire slides out and the rider falls. Mark McMaster Dear Mark and Tom, I could squirm (pun intended) about which tire the page describes as slipping more, but I think that it would be better to say that the slip (versus slide) is close enough to "a wee bit" to convince me that Tom has a reasonable point and that I was wrong enough that I need to say so. Thanks for sticking with your point, Tom. And thanks for clearing that up, Mark. Carl Fogel |
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On Sat, 04 Sep 2004 03:34:01 GMT, Mark McMaster
wrote: wrote: On Thu, 2 Sep 2004 11:39:45 -0700, "Tom Nakashima" wrote: wrote in message ... On Thu, 2 Sep 2004 07:33:13 -0700, "Tom Nakashima" Yes, Mark, one who understands motorcycling. Here's another link on a motorcycle slide bike course that one can enroll in. http://www.motorcycle.com/mo/mccustom/slide.html -tom Dear Tom, The page seems to suggest only rear-wheel power slides exiting paved corners. The apparatus appears to be designed to prevent the motorcycle rider from falling down if he exceeds the limits of traction. Am I mistaken? Carl Fogel Yes Carl Fogel that is correct, the lean slide bike apparatus is to keep the rider from falling down, however it not only suggest power sliding the rear wheel, but the front wheel also slides as well. I actually spoke with a motorcycle rider (co-worker) this morning who took the Keith Code course here at SLAC, the rear tire, as well as the front tire does slide in the corners with the control of the throttle. The front not as much as the rear. He also said your gauge for your limits of slide and lean angle is your knee touching the ground. Did you also read about the paragraph about controlled slide? Are you convinced now? Maybe you should take the Keith Code course yourself if you're still not convinced. -tom Dear Tom, Well, no, to be frank, I'm not convinced that racers are cornering so hard on pavement that their front tires lose traction and slide. The word "slide" might be a bit imprecise. However, wide tires rolling under high lateral force do exhibit what is known as a slip angle, caused as the rubber deforms as it rolls through the contact patch. This action of the rubber "walking" or "squirming" laterally makes the wheel act as if slipping sideways as it rolled. http://www.msgroup.org/TIP076.html What path would a motorcycle or bicycle follow if the front tire began to slide sideways under hard cornering? On a motorcycle, riders describe the feeling as "understeer" or "oversteer" (depending on which tire is slipping more), causing the path of the motorcycle to turn at a greater or less radius, respectively, than the steering angle would indicate. The contact patch of a bicycle tire isn't large or wide enough to exhibit any significant slip angle. Under hard cornering, a bicycle either tracks exactly as the steering angle requires, or the tire slides out and the rider falls. Mark McMaster Dear Mark and Tom, I could squirm (pun intended) about which tire the page describes as slipping more, but I think that it would be better to say that the slip (versus slide) is close enough to "a wee bit" to convince me that Tom has a reasonable point and that I was wrong enough that I need to say so. Thanks for sticking with your point, Tom. And thanks for clearing that up, Mark. Carl Fogel |
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wrote in message ... On Fri, 3 Sep 2004 19:52:23 +0100, "Trevor" wrote: wrote in message ... Now I'm truly baffled. I was assuming that you meant the tiny side road off the A494 running up from Bwlch-y-parc toward Moel Ethinen. Originally, you estimated a significant stretch of 10% grade. Are you saying that the A494 has a 10% grade somewhere around Moel Ethinen and that you were pedalling 70 mph down it? I'm hard pressed to find a drop of a hundred meters on the unfortunately crowded topo map in several kilometers on the A494 around Moel Ethinen--and that stretch ends in a 180-degree hairpin into Llanbedr-Dyffryn-Clwd. Other way 9kms. turn around, read my post, Gwernymynydd believed to be 1:10 not steep for these parts. Trevor Dear Trevor, Here's Gwernymynydd with the A494 running through it: http://www.streetmap.co.uk/newmap.sr...v=321500,36250 0&st=4&ar=N&mapp=newmap.srf&searchp=newsearch.srf& dn=616 or http://tinyurl.com/5tdz3 Is this is where you're hitting 70 mph with the help of a 15 mph tailwind and a 10% grade that is not considered steep for paved roads in this part of Wales? The contour lines are 10 meters and the map is 3000 meters wide. While the map is badly cluttered, the rise from the roundabout to the east to "PH" in the center appears to be on the order of 60 meters in 1200, rather closer to a 5%.grade. That'll be the bit I refer to as tapering out. The steeper section is the 1km to the west of Gwernymynydd crossroads and reading from an 1:50 000 sheet the 10m contour lines are less than 2mm apart making the grade steeper than 1 in 10 The crossroads also contain traffic lights (mostly) ;-} I'll try for a larger scale, I could then measure steepest grade with greatest accuracy. What are you disputing? Trevor |
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wrote in message ... On Fri, 3 Sep 2004 19:52:23 +0100, "Trevor" wrote: wrote in message ... Now I'm truly baffled. I was assuming that you meant the tiny side road off the A494 running up from Bwlch-y-parc toward Moel Ethinen. Originally, you estimated a significant stretch of 10% grade. Are you saying that the A494 has a 10% grade somewhere around Moel Ethinen and that you were pedalling 70 mph down it? I'm hard pressed to find a drop of a hundred meters on the unfortunately crowded topo map in several kilometers on the A494 around Moel Ethinen--and that stretch ends in a 180-degree hairpin into Llanbedr-Dyffryn-Clwd. Other way 9kms. turn around, read my post, Gwernymynydd believed to be 1:10 not steep for these parts. Trevor Dear Trevor, Here's Gwernymynydd with the A494 running through it: http://www.streetmap.co.uk/newmap.sr...v=321500,36250 0&st=4&ar=N&mapp=newmap.srf&searchp=newsearch.srf& dn=616 or http://tinyurl.com/5tdz3 Is this is where you're hitting 70 mph with the help of a 15 mph tailwind and a 10% grade that is not considered steep for paved roads in this part of Wales? The contour lines are 10 meters and the map is 3000 meters wide. While the map is badly cluttered, the rise from the roundabout to the east to "PH" in the center appears to be on the order of 60 meters in 1200, rather closer to a 5%.grade. That'll be the bit I refer to as tapering out. The steeper section is the 1km to the west of Gwernymynydd crossroads and reading from an 1:50 000 sheet the 10m contour lines are less than 2mm apart making the grade steeper than 1 in 10 The crossroads also contain traffic lights (mostly) ;-} I'll try for a larger scale, I could then measure steepest grade with greatest accuracy. What are you disputing? Trevor |
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wrote in message ... On Fri, 3 Sep 2004 19:52:23 +0100, "Trevor" wrote: wrote in message ... Now I'm truly baffled. I was assuming that you meant the tiny side road off the A494 running up from Bwlch-y-parc toward Moel Ethinen. Originally, you estimated a significant stretch of 10% grade. Are you saying that the A494 has a 10% grade somewhere around Moel Ethinen and that you were pedalling 70 mph down it? I'm hard pressed to find a drop of a hundred meters on the unfortunately crowded topo map in several kilometers on the A494 around Moel Ethinen--and that stretch ends in a 180-degree hairpin into Llanbedr-Dyffryn-Clwd. Other way 9kms. turn around, read my post, Gwernymynydd believed to be 1:10 not steep for these parts. Trevor Dear Trevor, Here's Gwernymynydd with the A494 running through it: http://www.streetmap.co.uk/newmap.sr...v=321500,36250 0&st=4&ar=N&mapp=newmap.srf&searchp=newsearch.srf& dn=616 or http://tinyurl.com/5tdz3 Is this is where you're hitting 70 mph with the help of a 15 mph tailwind and a 10% grade that is not considered steep for paved roads in this part of Wales? The contour lines are 10 meters and the map is 3000 meters wide. While the map is badly cluttered, the rise from the roundabout to the east to "PH" in the center appears to be on the order of 60 meters in 1200, rather closer to a 5%.grade. That'll be the bit I refer to as tapering out. The steeper section is the 1km to the west of Gwernymynydd crossroads and reading from an 1:50 000 sheet the 10m contour lines are less than 2mm apart making the grade steeper than 1 in 10 The crossroads also contain traffic lights (mostly) ;-} I'll try for a larger scale, I could then measure steepest grade with greatest accuracy. What are you disputing? Trevor |
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