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  1. 2 likes
    Drag racers rebuild their engines after each run. You really think cost is preventing them from running a skinny tire if they could gain a tenth? No. I have corresponded with the author of the article you link and while he might understand physics, I'm not convinced he understands motorcycle dynamics in a practical sense. The truth lies somewhere between the two. I have yet to find the answer. But the closest reasoning I've read that the coefficient of friction rather than being a constant can vary with temperature. Large contact patch might resist temperature change hence resist changes in coefficient of friction. Additionally, coefficient of friction does not accurately describe a rolling and cornering tire that operate with some slip angle. The tire is not stationary but not sliding either. No, it is too simplistic to say contact patch doesn't matter. From a practical motorcycling sense, much of Code's teaching talks about contact patch and friction. Based on all that practical experience of thousands of riders, there is some truth to the statement. Just my opinion.
  2. 2 likes
    At Buttonwillow RT in CA, turn 1, clockwise, April, I attempted a quick flick at 25 mph. It was session 2, first lap, and i went down. The front tire lost traction. After that crash i recalled the T2 video where the question is posed to the class, "Do you quick flick the bike when you're tires are cold?". The resounding answer: NO! The morning temperature was about 50F. Street tires. No tire warmers. I cancelled my late November track say in Chuckwalla without regret. Some like it hot.
  3. 2 likes
    The short answer: you have to work up to it and feel it out. The longer answer: Testing the grippiness of your tire must be done gradually, the idea is to increase lean angle gradually so that if the tire begins to slide there is some warning and opportunity to save it. The most pro coaches I have talked to on this advise gradually adding a little more lean at a time (corner after corner, or possibly even in the same corner if it is a long one) to feel out the traction, as opposed to just whacking it over to maximum lean and hoping for the best - because if you go too far too fast you will not have enough time to "sample" the traction and see how it feels, and know when you are approaching the limit. Some tires will have a specific feel to them when they are cold: the Dunlop slicks, for example, have a tendency to make the bike want to stand up in the corner and that is a good indicator that they are very cold. The carcass is stiff and reluctant to flex so when you lean into the corner it resists and sort of pushes the bike back up. Some other tires just feel a bit "wandery" in the corner, like they are sort of weaving around slightly, instead of feeling planted. If you have ridden in rain or ridden dirt bikes in the mud, you can recognize the feel of little slides, and little slides like that are your warning that you are at about the limit of traction for the conditions and the tire needs to warm up more before you can lean over any farther. It is a great exercise, when opportunity presents (winter is coming!) to pay VERY close attention to how your tires feel when stone cold, to develop a sense for it with your own bike and your own tire brand/model. It is difficult to quantify how long tires will take to warm up because it depends on tire type, air temp, track temp, wind conditions, how hard you ride, etc., so the best solution I know of is to feel it out carefully.
  4. 1 like
    That should bring your chest closer to the tank and your head a bit forward and to the inside. But some of it could be your fit on the bike, if you feel there is a reach to the bars then it's hard to get a good position. If looking from the front, you should be to the inside of the centerline and along side the bikes CoG.. as shown by Marquez and tried by me..
  5. 1 like
    I agree that managing the contact patch, for all practical purposes, is the way to improve cornering performance. It may or may not be the size of the contact patch vs the forces you apply on the patch, but the logic to balance the chassis and the weight on each tire gives the same result. I don't see this is contradicting anything of the Code principals.
  6. 1 like
    If you read through the article I posted a link to, it concludes that wider tires primarily are for wear reasons. As we all know, a rubber tire sacrifices itself to provide the friction (all the gum balls on your front tire after a track session prove this is so). A small tire dealing with significant friction demands, and in drag racing probably being overloaded will wear fast. So if you had the smallest tires that could support the weight of the car and did a run, you would likely destroy them due to friction heat and mechanical stress. If you were really serious about winning a drag, you could have single pass tires that had just enough strength for a run and then die. They would be smaller and lighter. But you would change tires every single pass. So the extra rubber is for wear and handling of forces - vertical, lateral, roll on the sidewalls/carcass, flex to absorb acceleration and deceleration shock, bumps and so on. It doesn't provide more friction or grip.
  7. 1 like
    Great. Practice is a good way to improve your BP. What I see from your photo, you might put some attention to your head position. In that photo a good head position will be if your head is near of your left hand, close to touch it. I know, it isn't easy but if you practice often you will get it. If you Focus in that your back also will form a V shape with the bike axis, and your right arm will be fully extended. thats was my 2 cents. keep riding!