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Quick Turning.


Jasonzilla
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Our trackday "season" has started and I hit Inde. One thing that's always been an issue for me is quick turns. It was a huge point of frustration before, during, and since school, and I'm always working overtime to fix this. Watching video, reviewing lessons from school, practicing.

 

Before going through school I had to take off too much speed to get into corners. Two step fixed that somewhat, but I was dropping the bike real fast and wasn't able to .

 

Since school (and seeing Lenz in action a few times) I was working on getting the bike over as quickly as possible. I've seen few pros drop a bike into a corner as fast as Lenz could. But I wasn't getting full lean and was losing speed while concentrating on getting over as far as possible. I wasn't gaging the corners correctly, couldn't hit the corners at speed.

 

This weekend I chose to slow it down and work on entry speed. I know the pro racers I've watched are taking defensive lines so they don't get over as quickly as when they do qualifying laps, but I figured I'd try it. Work on entry speed. It worked. In one trackday I managed to knock 15-20 seconds off my laptimes. I'm getting the bike over nearly as quickly as I was before, but am going into the corners with more lean and getting through the corners much faster, feeling more planted and able to get on the throttle quicker because I'm in a more comfortable position sooner.

 

The quick turn session was pretty much useless to me during the school because the key to quick turning, the two step, wasn't taught until the next session, or a couple sessions, later. Did quick turning take this much work to catch onto for the rest of the people who attended school? Do people who didn't attend a CSS figure out quick turning, or was it shown in a way that is easily understandable. I help newer riders, and being able to effectively describe this, verbalize it, is the key to properly relaying info.

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Hi Jason

Quick turning or the quick flick is something I am personally always working on improving, If I dont work at it I seem to get lazy with it so I always focus alot of attention on it during the first session of the day. My level 3 coach even had me do the level 1 off track drill to help me with it! The thing is I fully understand how counter steering works, having my forearms in line for maximum movement on the bars, weighing the outside peg etc. In perfect hot dry conditions I have no problems, infact I think I could probably quick turn faster than I do!

The release of the TOTW 2 dvd threw some confusion my way as the section that covers quick turning Keith asks the kids in the classroom when would you be unable to quick flick the bike, a few obvious answers such as, cold tyres, new unscrubbed tyres, overly worn tyres, but the one that threw me was he says you cant do it on a wet or slippery surface, but that was the conditions I learned the quick turn drill, confused!

Anyway I will be on track this Sat so will put some attention on it and see how I get on!

 

Bobby

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I'm have similar confusions to Acebobby's reply.

 

I also learnt the quick turn on a wet day and (for levels 1 & 2 anyway) embraced it with a passion. In fact my L2 coach pointed I was quick turning too aggresively (this was in the dry BTW), so I tried to tone it down.

 

Following Level 2, I was happy to quick turn and everything was great until I had 2 front end low sides, which I have put to bed in my mind as being due to a combo of cold tyres, not using my legs properly and it being wet. That's all well and good, but there is still this nagging about quick turning and just how aggresive to be.

 

I also saw that part of the TOTW2 DVD and that confused me further.

 

I also recall reading some posts on here that, with warm tyres and dry conditions you actually can't quick turn at a rate fast enough to overcome the front wheel friction - is that right, or an over simplification? Assuming your body weight is already over the front and your off the throttle, I guess I could buy into that......putting it into practice is a bit more worrying for me. Something for my Level 4 coach next year :P

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For me the keys to getting increased turn-in speed (and corner speed) were a combination of countersteering but also reference points - mainly the run in point but I was probably aiming for the same apex most of the time as I built up speed. So yes, also the 2-step because I'm looking for one RP then the next. The learning points in the school are something that you have to go around a number of times, maybe they needed to make it clearer how some of them go together, but some people interpret explanations very diffferently to others. Sometims you just have to have a go and make a fist of it, which is usually where the coaches come in because they'll spot you trying one thing at the expense of another.

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Ok so I've been thinking about quick turning and front end grip. I'm a civil engineer by trade, so have been applying some of my trade knowlege to my though process - this is what I have come up with.

 

Putting VERTICAL load on the front wheel is good for front end grip. Principally more vertical load *has* to result in more grip........but, because the bike is also leant over, there is also a horizontal component to this and the more you lean the more the resultant force transfers from vertical to horizontal. This would move you towards a sliding condition.

 

So back to my query on whether itis possible to quick turn too fast....(assuming no rain/bad surface/tyre issues) I would say no, if you are decelerating with weight over the front i.e. hanging off properly. This is because the deceleration causes vertical force to increase and horizontal force to reduce. If you turn rapidly then this permits the sudden increase in horizontal force to be accomodated due to the vertical force still being high. You finish turning and then accelerate as you pick the bike up (load transfers to the rear and vertical load reduces on the front, but this is now ok, because the ever reducing lean angle also reduces the horizontal componant.

 

Conclusion - I am currently turning to slowly and need to change this!

I only get away with is because my lower speed (and smooth riding - HAH!) keeps me away from the limit of my tyre grip. If I start going faster my slow turning WILL eventually bite me in the backside.

 

Without trail braking, you can't quick turn too fast - wet or dry. In the wet an uplift component is added, effectively subtracting from the vertical force. So to get around this you don't actually turn slower, you just don't lean as much. (All things being equal, the turning will actully be over quicker, because you aren't flicking the bike as far!

 

Am I right here, or have I missed something? Perhaps you would be a lot more careful with the brakes in the wet, because front wheel braking whilst tipped over would dynamically load the front and at high lean angles would contribute more dynamic horizontal componant than vertical.......I only put this on as afterthought because I don't really trail brake much, if at all.

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I would argue that you can quick-turn too fast in the wet - see Keith's comments to someone above about cold tyres. Both situations are reduced grip. You have more or less the same weight (downware force) on the front tyre, but less grip available ergo yes you could slide it if you're brutal enough.

 

Here is how I'm thinking about it in my mind:

 

(BTW I ended up writing a lot, so if you want a cut to the chase questions, it is this -

 

CUT TO CHASE - Q1. Does the action of quick turning load your bike suspension? Or is the loading a result of lean/camber angle, corner speed and acceleration, with the turning just a rotation force.

 

Q2. What do you do in the wet?

a, Turn at a slower/same rate.

b, Lean less/ the same.

c, Do neither different and just reduce entry speed?

 

If you want to read the long rambling version then read on.....

 

LONG VERSION.....

 

The wheels of a bike are like any other loaded surface. There are four things that affect sliding resistance:

 

1. vertical Load (determined by bike / rider weight, and relative distribution over the wheels resultant from body position and any deceleration or acceleration)

 

2. Uplift forces which result from either

(i) surface bumps

(ii) surface water

 

3. A co-efficient at the surface /wheel interface. This may be made up of 2 components.

(i) tyre suface adhesion/friction (variable dependent upon temperature)

(ii) Debries / oil / other surface defects (which clearly varies)

 

4. 'Clean' Track surface friction

 

All the above can be summed up by:

 

Resistance = ((Load - Uplift) * (interface co-efficent * (the tangent of clean track surface friction angle))

 

So when we go around a corner we have a horizontal (sliding) force applied through the tyres which is a result of:

 

((Bike + rider weight) * (Speed) * (acceleration) * (tangent of resultant reaction angle,which is dependant upon lean angle, the tyre surface adhesion/friction and any corner camber)

 

As long as sliding resistance is at least equal to sliding force we have no problem.

 

So in the wet we have an uplift force to reduce load and a reduced interface co-efficient (due to colder tyres). The reduced interace co-efficent will both reduce resistance and also apply an increased horizontal force.

 

But (at the moment.....awaiting correction! :P ) I am standing by the comment that this would principally be controlled by a reduced lean angle, or some other means of reducing the horizontal force, and not rate of turning.....

 

This is because I am thinking that the action of turning has a rotation around the point where the tyre meets the track. So if the tyre contact point is a pivot point and the turning action is solely rotational, it can not, by this definition, add any further horizontal force.

 

This is why I came to the conclusion that the rate of angle change is not important in isolation. It is the the sum total of imposed sliding forces that control this, and reduced lean angle (or reduced entry speed) is one way of restoring it.

 

So the long question is really no different from the 'Cut to the Chase ones - 'how much, if at all, does turn rate affect the horizontal/sliding force' and why?

 

Sorry for rambling - this is bugging me! <_<

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I'm not sure that with the quality of todays average sportbike tire that you can go into a corner (on warm tires on a clean dry surface) off the gas and brake and be able to quick turn (QT) past the traction threshold of the tire.

 

"How much, if at all, does turn rate affect the horizontal/sliding force and why?"

I think it depends on a number of things that ultimately end up asking about where the tire traction limits are. If you have X amount of traction, you can put so much horizontal pressure onto it. Just like being up straight. If you whack the front brakes without flipping the bike, the slightest bit of turn is going to cause the bike to slide out from under you. You've exceeded the small amount of horizontal pressure the bike can handle with the available traction limits being used to stop the weight of the bike, rider and momentum.

If you're trail braking into a turn, quick turning while chewing up so much of your traction limit is going to put you past what the tire can handle and it will lose traction. If traction limit is 100, braking to reduce speed takes up 60, you have 40 to play with in leaning. Any more and you've exceeded the tires ability to hold traction. The basics are to brake, come off the brake, turn, throttle once you've completed the turn. Turning while off the gas and brake is the time when you'll have the largest amount of available traction on the front tire. The front will get weighted by the deceleratory forces, applying increased traction. All is right with the world.

During racing, advanced riders who trail brake into a corner aren't going to QT the bike. That's why it's said you have a qualifying line and a racing line. During their qualifying runs riders will come off the brake, get the bike over, and shoot through the corner. When racing, they understand they're using up that traction limit in braking and turning, and that force is using up their available traction limit. If they try to QT the bike, they're going to move their ratio past any traction requirements a horizontal tire will be able to handle.

That's how someone outbraking another rider into a corner is going to lowside or have to pick the bike up going in. He started braking too late and the bike can't handle the added weight to the front tire and he either goes for it anyway or realizes this and picks the bike up. If a rider is undercut and uses the front brake, he's, again, going to quickly surpass the available traction limit, only with a sudden addition of weight and momentum to the front tire.

Riders who are cruising through a corner and apply a sudden amount of gas have the potential to lose the back end suddenly. Too much, and you've disallowed the suspension to transfer the weight of the bike and momentum to the rear. If there is no pressure on the rear tire and you don't give the bike time to adjust, the tire alone will not be able to handle it. A weighted and unweighted tire will also have a different traction limit. That's where Throttle Control Rule #1 comes into play. Smooth. Let the suspension do it's job. Let the tire adjust to all the changes in pressure. Of course, too much throttle altogether and you'll still overload the rear tire. If you're vertical you'll burn out. That's the rear tire exceeding the traction limit. Overloading it in this instance simply means you're adding enough throttle on top of the amount of weight applied to the tire plus acceleration already applied to the horizontal traction limits causing you to surpass the available traction limit.

THIS is where the pick-up drill comes into play. Reducing the horizontal pressure (by picking the bike up) adds the more available traction and allows for more throttle.

If you go watch a newer rider at his trackday, you'll see they aren't wrecking because they're surpassing the traction limits, but because of control of the bike, or their lack of control. They don't slide the tires, they don't feel any slide. They don't know how much force they can apply to the tires with their available traction limits (which is A LOT MORE than they're already applying for their amount of lean). In braking into a corner, this is why the bike is going to be picked up and they're going to shoot off the course. They'll think they're exceeding their traction limits. They don't know that, they just think they're going to wreck.

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I'm not sure that with the quality of todays average sportbike tire that you can go into a corner (on warm tires on a clean dry surface) off the gas and brake and be able to quick turn (QT) past the traction threshold of the tire.

What about pushing the front, Jason?

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I will not try to give the impression that this is a concept I fully grasp, but it could be that both of you are correct - that the turning itself won't cause grip to be lost and that turning too quick for the available grip will cause a crash. Contradicting? Apparently, yes. But I imagine that the turning itself isn't problematic - having the tyre at an angle to the direction of the vehicle and the resulting pushing force from the rest of the bike following the front tyre contact patch will cause a skid. And there are likely several more forces that comes into play. However, since the bike is moving and changing direction and angle of lean and whatnot instead of sitting stationary, the rate it changes its attitude will have an impact on grip even if the initial split second of force doesn't cause a direct issue.

 

Either that or I'm way off tongue.gif

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I'm not sure that with the quality of todays average sportbike tire that you can go into a corner (on warm tires on a clean dry surface) off the gas and brake and be able to quick turn (QT) past the traction threshold of the tire.

What about pushing the front, Jason?

 

How does "in neutral (clutch in)" work for you?

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Well, in theory I'm supposed to be doing nothing - LOL.

I only made the comment because I'm just not yet convinced that the front end can be planted 100% of the time. Everything has limits. But if you have evidence to the contrary...

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  • 1 month later...

Would be good to hear from a coach on this. Feel free to blast me out the sky if I'm wrong but is it not very rare to get a front end wash-out at the start of a turn? normally mid to late turn (whilst still leant over) when accelerating? However I've always assumed its very possible, for instance if the front forks are bottomed out when you turn. If I'm well off please let me know as I'm always looking to learn from the forum.

 

Ollie

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The release of the TOTW 2 dvd threw some confusion my way as the section that covers quick turning Keith asks the kids in the classroom when would you be unable to quick flick the bike, a few obvious answers such as, cold tyres, new unscrubbed tyres, overly worn tyres, but the one that threw me was he says you cant do it on a wet or slippery surface, but that was the conditions I learned the quick turn drill, confused!

Anyway I will be on track this Sat so will put some attention on it and see how I get on!

 

Bobby

 

Just read this thread and there is a lot to be addressed. I'm going to start with this one.

 

You can turn quickly in the wet. Can you turn it as quick and to the same lean angle you do in the dry? NO. Keith is comparing apples to apples on the video. If you are at a track and it is a perfect day for quick turning (conditions are good, tires are warm, fairly new, etc) and you have success with it, yet it starts raining and the pavement gets slippery, then you can't turn it as quick as you did when it was dry. But you can still turn it quicker - there is a scale or degree of quickness here.

 

The rule is straight from Twist II is: "As quickly as possible in every turn.", "as-quickly-as-possible means: for the demand of the turn".

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It is possible, but how many crashes has anyone seen that are a result of turning it too fast? PROVIDED the brakes weren't on, and the tires were actually warmed up, and the asphalt wasn't slippery.

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Even if smashing the bike down in the dry isn't something you want to do, think about increasing the power you put into the bar by something real to you... maybe 1% or 5% more power... with every % more power into the bars comes a quantifiable improvement in how quickly you get onto your chosen line.

 

Give it a try within your own comfort zone... even in the car :D :D :D

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I had an incident at Thunderbolt, I did the quick turn more aggresively than usual, and ended up scraping my foot peg which sent me into "sphincter overload".

 

But NO I didn't lose the front tire.

 

"S.O", priceless!

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