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Trail Braking Usage


tweek
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Tweek--let's check out the physics on this (rudimetary). You roll on the throttle, after you turn in, then you roll of the gas (not even using the brakes), what does the bike do, if you are doing absolutely nothing to the bars--what happens to the line, where does the bike go when the gas is rolled (or chopped off)?

 

Rolling off the throttle should tighten the line.

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BTW - anybody that thinks all this is pointless: I just chopped another 3 seconds off my best time around ECR! Spending some time thinking about whta is going on helps me.

 

By the way - having the front end push while you're leaned over is scary as hell. But just a touch of throttle made it all better.

Spinning up the rear is more fun. But still pretty scary.

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I find it MUCH harder to get my gsxr600 leaned into a corner while on the brakes. 85% of the bikes weight is on the front tire, I don't understand how it could possiby turn easier. It also feels like the bike turns much sharper on the throttle comaired to being on the bakes but I haven't messed around with trail braking a street bike much.

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Tweek--let's check out the physics on this (rudimetary). You roll on the throttle, after you turn in, then you roll of the gas (not even using the brakes), what does the bike do, if you are doing absolutely nothing to the bars--what happens to the line, where does the bike go when the gas is rolled (or chopped off)?

 

Rolling off the throttle should tighten the line.

 

 

Not initially--it will run wider at first.

 

CF

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I'll play around with it on Sunday. I apperciate the push back to make me think deeper about this. Like I said before: I believe it does make a difference.

 

Weather this weekend should be perfect. I'm going to do another session w/ Ty on Friday and go play on Sunday. I'm really hoping I can cut out another 2 or 3 seconds. A friend of mine needs to be stuffed in 9. I'll get the video to show why in a bit.

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Tweek--let's check out the physics on this (rudimetary). You roll on the throttle, after you turn in, then you roll of the gas (not even using the brakes), what does the bike do, if you are doing absolutely nothing to the bars--what happens to the line, where does the bike go when the gas is rolled (or chopped off)?

 

Rolling off the throttle should tighten the line.

 

 

Not initially--it will run wider at first.

 

CF

 

First time I heard this, I found it hard to understand and hard to believe. I didn't ever REALLY understand it until I watched the Twist of the Wrist II DVD, there is a computer generated animation that shows what happens, in slow motion, and explains WHY, and WOW did the lightbulb come on for me when I saw that!

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I find it MUCH harder to get my gsxr600 leaned into a corner while on the brakes. 85% of the bikes weight is on the front tire, I don't understand how it could possiby turn easier. It also feels like the bike turns much sharper on the throttle comaired to being on the bakes but I haven't messed around with trail braking a street bike much.

 

So... if you think of a corner where you are hard on the brakes on the entry, when you make your steering action, what is the angle of your arms relative to the bars? Is your body position the same when you turn on the throttle versus turning on/after the brakes? Does the angle of your elbow change?

 

Also, just curious - some people push the inside bar to turn and some people pull on the outside bar, some peope do both, which do you use? Do you do it the same way on throttle versus on brakes? Do you find that the bike, when trying to turn while on the brakes, is harder to turn on lefts, or rights?

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First time I heard this, I found it hard to understand and hard to believe. I didn't ever REALLY understand it until I watched the Twist of the Wrist II DVD, there is a computer generated animation that shows what happens, in slow motion, and explains WHY, and WOW did the lightbulb come on for me when I saw that!

 

 

Good point Hotty, that DVD does show it well.

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I thought trail braking was more a racing technique, which when entering a corner, is slower than a proper turn when you use the proper brake point, TP, apex, and exit (given, of course, good throttle control). I think it's slower to brake brake brake, turn/brake, turn/trail the brake, get on it, than to brake brake brake, turn, throttle up. I do it for fun and because it's a good technique to be familiar with, but it's a lot easier for something to go wrong while trail braking (run wide, become nervous and look who knows where, slide, etc).

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The thing that bothers me about trail braking is that you are asking the tire to do multiple things at once: change direction and change speed. If you have $10 of traction available, how do you use it to get around a turn quickly? It would seem that using all $10 for changing speed (braking) first and then using all $10 to change direction would make the most sense.

 

But is it really that simple? I don't think people using all available traction for braking. Maybe only $7 or $8. And I bet even fewer people get anywhere near using all $10 for changing direction unless then are then proceeding on to crashing. Maybe $5 or $6.

 

Wouldnt that leave the door just a little open to a little blending of the two?

 

I think part of the reason people trail brake is getting the corner speed set correctly. It's really hard to come up on a turn, brake to the entry speed and then continue the process. The result for me (and I bet a lot of people) is that they end up over braking and entering the corner a *LOT* slower than they are actually capable of. The upside is that there is a huge margin for error. The downside is that you are several seconds slower than you are capable of.

 

However, to be clear: I'm not judging which technique is better. I'm trying to understand what is going on so either is available to me depending upon the circumstance.

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The thing that bothers me about trail braking is that you are asking the tire to do multiple things at once: change direction and change speed. If you have $10 of traction available, how do you use it to get around a turn quickly? It would seem that using all $10 for changing speed (braking) first and then using all $10 to change direction would make the most sense.

 

But is it really that simple? I don't think people using all available traction for braking. Maybe only $7 or $8. And I bet even fewer people get anywhere near using all $10 for changing direction unless then are then proceeding on to crashing. Maybe $5 or $6.

 

Wouldnt that leave the door just a little open to a little blending of the two?

 

I think part of the reason people trail brake is getting the corner speed set correctly. It's really hard to come up on a turn, brake to the entry speed and then continue the process. The result for me (and I bet a lot of people) is that they end up over braking and entering the corner a *LOT* slower than they are actually capable of. The upside is that there is a huge margin for error. The downside is that you are several seconds slower than you are capable of.

 

However, to be clear: I'm not judging which technique is better. I'm trying to understand what is going on so either is available to me depending upon the circumstance.

 

Just my opinion on this... to your point, about using less than your $10 of traction - picture a wide, roughly U shaped decreasing radius turn, after a high speed straight. It will end up a double apex turn, and you don't want to give up your straightaway speed any earlier than you have to. I don't like trail braking but in that scenario I would probably bend it in and trail brake to, or maybe even past, the first apex, because I am still slowing down for my second turn point and the first turn-in is not that sharp, so I have enough available traction to brake while I am turning. In that case, trail braking seems like a good move to keep someone from coming up your inside when you are entering the turn. For sharp, tight, quick-steering turns, it wouldn't even occur to me to trailbrake, it's too much to think about and too easy to overload the front tire.

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The thing that bothers me about trail braking is that you are asking the tire to do multiple things at once: change direction and change speed. If you have $10 of traction available, how do you use it to get around a turn quickly? It would seem that using all $10 for changing speed (braking) first and then using all $10 to change direction would make the most sense.

 

But is it really that simple? I don't think people using all available traction for braking. Maybe only $7 or $8. And I bet even fewer people get anywhere near using all $10 for changing direction unless then are then proceeding on to crashing. Maybe $5 or $6.

 

Wouldnt that leave the door just a little open to a little blending of the two?

 

I think part of the reason people trail brake is getting the corner speed set correctly. It's really hard to come up on a turn, brake to the entry speed and then continue the process. The result for me (and I bet a lot of people) is that they end up over braking and entering the corner a *LOT* slower than they are actually capable of. The upside is that there is a huge margin for error. The downside is that you are several seconds slower than you are capable of.

 

However, to be clear: I'm not judging which technique is better. I'm trying to understand what is going on so either is available to me depending upon the circumstance.

 

This part got me wondering: When you push the front do you have 100% traction applied to the tarmac? Can the front push at anything less than $10? Does the tire deform to give it's full $10 when initial countersteering input is initiated or does traction "catch-up" after the bars turn in?

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Tweek--let's check out the physics on this (rudimetary). You roll on the throttle, after you turn in, then you roll of the gas (not even using the brakes), what does the bike do, if you are doing absolutely nothing to the bars--what happens to the line, where does the bike go when the gas is rolled (or chopped off)?

 

Rolling off the throttle should tighten the line.

 

 

Not initially--it will run wider at first.

 

CF

 

Figured out why - throttle, just like the brakes changes the suspension geometry. The throttle in this case, rolling off, causes two things to happen:

1) weight moves forward compressing the front suspension. Which all on its own should cause the line to tighten.

However:

2) The rear end also compresses b/c the chain is now slack allowing the swingarm to move up.

 

The bike loses ground clearance. Weight is on the front end, but the swingarm is now flat changing the steering head angle. so on and so forth.

 

Which leads back to what you guys have been saying all along: once you are leaned over and rolling on the throttle; don't stop! Keep rolling it on.

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