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Thielert

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Everything posted by Thielert

  1. Crash; Maybe it's just me but it's my sense that the bike begins its transition to the opposite direction before the front wheel is pointed there...but I could be wrong. Rain I think this statement from the Wikipedia article confirms your senses are correct:
  2. Please go back and read this excerpt from Wikepedia very carefully with reference to steering torque and steering angle. The direction the tire is pointed is steering angle, the force applied at the handlebars is the steering torque. The two may be in the same direction or in opposing directions as clearly stated in the article.
  3. I'll try to really get loose on the bars next time out and see if I'm unintentionally countersteering my way out of the turn. Anyway, weighting the outside peg seemed to fix it.
  4. This stuff is making my head hurt!
  5. From James R. Davis "neutral steering fact or fancy" "I have maintained that the rider MUST maintain some measure of negative torque throughout the turn in order to maintain it. That is, he must maintain a certain amount of forward pressure on the inside grip throughout the turn else the bike will, of its own accord, attempt to straighten itself out and abort the turn - ending up moving in a straight direction. However, there are 'tuning points' where a specific speed and turning radius can result in a motorcycle that requires no steering input to maintain its path."
  6. More info, the turn in question is crested, you are still going uphill at the turn in point and then the road begins to fall away. Entry speed is about 125 mph and there may be significant camber and radius changes throughout. I know I'm hard on the gas throughout but that may be to counteract aerodynamic drag and rolling resistance. I'm no expert so I'm just trying to figure out why I'm having to maintain constant negative steering torque (countersteer) throughout to make the corner. If I ease off, I go wide.
  7. Hi Matt, now you have me really confused! From Wikepedia: "It is also important to distinguish the steering torque and steering angle necessary to establish the lean required for a given turn from the sustained steer torque and steer angle necessary to maintain a constant radius and lean angle until it is time to exit the turn. The initial steer torque and steer angle are both opposite the desired turn direction. The sustained steer angle is usually in the same direction as the turn, but may remain opposite to the direction of the turn, especially at high speeds.[5] The sustained steer torque required to maintain that steer angle is usually opposite the turn direction.[6] (See the graphs to the right.) The actual magnitude and orientation of both the sustained steer angle and sustained steer torque of a particular bike in a particular turn depend on forward speed, bike geometry, tire properties, and combined bike and rider mass distribution." Please comment on their reference to "sustained steer torque" in a turn as this sounds exactly as what I am experiencing. Corner speed is above 125 mph I'n this particular turn where I am using countersteer torque.
  8. I just finished TOTW II a few days ago and decided to give weighting the outside peg a shot. I'm in the process of completely revamping my body position and riding style after six years of sportbike riding so all of this is taking conscientious effort and is like taking two steps forward and one step back. The hangoff was unnerving at first but weighting the outside peg is giving me a more "locked in" feel so I don't feel like I'm going to fall off the bike. The biggest payoff so far from weighting the outside peg though has been the pivot steering effect which solved a problem I had with running wide in fast sweepers. I blamed it on everything from suspension setup to decreasing radius and off camber turns, nether true. I press hard on the outside foot peg now and almost by magic my line tightens up and I'm back hard on the gas.
  9. I just finished TOTW II a few days ago and decided to give weighting the outside peg a shot. I'm in the process of completely revamping my body position and riding style after six years of sportbike riding so all of this is taking conscientious effort and is like taking two steps forward and one step back. The hangoff was unnerving at first but weighting the outside peg is giving me a more "locked in" feel so I don't feel like I'm going to fall off the bike. The biggest payoff so far from weighting the outside peg though has been the pivot steering effect which solved a problem I had with running wide in fast sweepers. I blamed it on everything from suspension setup to decreasing radius and off camber turns, nether true. I press hard on the outside foot peg now and almost by magic my line tightens up and I'm back hard on the gas.
  10. I've recently started using this technique and it really solves a problem I call Aero-steering for want of a better term. That is where a buildup of aerodynamic forces on the rider pushes him back I'n a high speed sweeper and eases up the countersteering pressure on the inside bar, I'n effect countersteering the bike out of the turn. I noticed this effect on a couple of my favorite high speed sweepers, I had reached the false conclusion that I was taking the corner as fast as I could go and SR#1 kicks I'n and you ease off the throttle to finish the corner. Pressing down on the outside footpeg creates an action-reaction pair that automatically increases counter steer pressure on the inside bar and the line tightens up, you can't stop it! The net effect is you're back on the gas and taking the corner at a higher speed. What I found cool was that pushing off on that outside peg requires no conscious effort to push forward on the inside bar and tighten up your line, it's almost like steering with your foot. This is probably old news to most but a "eureka" moment for me.
  11. Fascinating discussion here and one that is hard to wrap ones head around as it seems counterintuitive. I remember the same experiment in a college physics class and it always amazed me that surface area had no affect on the outcome. I think someone might have hit the nail squarely on the head when they suggested that a skinny tire and a fat tire with the same loading would work equally well initially but the skinny tire would soon experience melt down changing it's chemical properties along with it's coefficient of friction. It would be interesting (and entertaining) to see a top fuel dragster equipped with both types of tires and data log the first few miliseconds of acceleration. It might turn out that skinny delivers the exact same acceleration characteristics for a split second then goes into early melt down mode and starts spinning wildly leading to further destruction. The fatter tire will absorb the huge power loading and live, hopefully to the end of the quarter mile. In the end, the fat tire has an advantage at the end of the track but not at the beginning. Only a sensitive gmeter could record such an event as it would occur over the briefest period of time. So as I see it, the physics don't lie, there are just mitigating factors in the real world that come into play.
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