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Can Quick Turn Be Overdone?


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  • 2 weeks later...
On 6/9/2014 at 4:59 PM, Hotfoot said:

Yes, exactly. So Pivot Steering can get you locked in properly, Knee to Knee will help you STAY locked in throughout a transition, and Hip Flick makes the transition very quick so you can get it done before having to steer the bike. Of course there is much more to the story and it is all presented in Level 3 but the basic answer to Lnewqban's question is that you transition the body before you steer the bike in a chicane, if possible, and you should have the lower body locked-in so as to get the most powerful and accurate steering input you can.

I NEED TO GO TO LEVEL III and IV!!!!! 

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  • 4 weeks later...
On ‎2‎/‎28‎/‎2017 at 3:27 PM, Jaybird180 said:

Chapter 17 of TOTW II represents that learning to QT solves all of the SRs. Can this be true???

I'm very interested in testimonials of how QT has resolved your SRs.

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I re-read this entire thread and all cited links to hopefully find an answer to a question. In T2 DVD one of the cautions given for QT is that it shouldn't be done on cold tires. How do you know the tires are ready for QT? And certainly since nothing in this universe is absolute, there must be a "scale of readiness" to ask for performance from the tire; how do you perceive such a scale and apply pressure accordingly without exceeding the limits of readiness?

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20 hours ago, Jaybird180 said:

I re-read this entire thread and all cited links to hopefully find an answer to a question. In T2 DVD one of the cautions given for QT is that it shouldn't be done on cold tires. How do you know the tires are ready for QT? And certainly since nothing in this universe is absolute, there must be a "scale of readiness" to ask for performance from the tire; how do you perceive such a scale and apply pressure accordingly without exceeding the limits of readiness?

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.

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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.

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  • 1 month later...

Wish I had a computer to look at the video frame by frame... but I don't think there's anything too mysterious happening here...

For those who have ever done a quick change of direction through a slalom or short chicane you might have noticed that it takes very little throttle (or any at all, if the steering rate is so quick?) to lift the front wheel as the bike is coming upright on the change of direction. This is because the steering rate is so great, you have the inertia of the bike coming from lean to upright, the mass of the bike combined with that inertia means that it wants to keep going up - hence lifting the front wheel. If you're then trying to lean the bike over in the other direction while the front wheel is in the air... well you can guess what happens. 

I've also seen this with strange geometry/weighting. It was on a work delivery scooter, bit of weight in the top box, a quick-ish u-turn or even just straightening up quickly out of a regular corner would bring the front wheel off the ground and cause a decent tank slapper if not controlled properly. 

Given the extremes that MotoGP racers are dealing with it wouldn't surprise me if Vinales front wheel came off the ground and caused him to crash. 

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I think you nailed it.  Just for the sake of non physicists, the rapid quick flick produces an upward force which decreases front tire contact patch area, and, applying throttle further decreases the front tire contact area, maybe even to zero, and upon leaning in the opposite direction, the front tire regains traction and because the front wants to self correct, the tank slapper motion begins?

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