Cornering Theory (split from High side thread in Crash Analysis)

[Holeshot]

If you keep a little lean angle in reserve, and you're in too hot, you can just lean it over and get on the gas and you will tighten up your line. Leaning the bike tightens the line. You need more speed to hold more lean angle.

A few things: no one we (Dave and I) ride against keeps "lean angle in reserve"...it's straight up and down to the deck in motion and done...

More: You DO NOT want to get into the habbit of ADDING lean angle and THROTTLE. That's the reverse of a correct technique. We want to give away lean angle as we add throttle. We want to give away brake lever as we add lean angle. Not to mention, adding throttle in practice, increases trail...making a bike take a wider arc.

And still more: Leaning a bike does nothing. it does not change the direction of the bike, nor tightens a line unless the front tire steers MORE into the turn. Steering is what will tighten a line, not leaning. And LESS speed allows MORE steering...hence the reason for trail braking, rear braking to tighten a line, etc.

I'm sorry, but you've got many of the concepts backwards IMO.

The problem is that if you've truly committed to the turn too hot, braking will cause you to crash instantly. If you have enough traction to brake, you've got plenty of traction to turn. If you've got no traction to turn, you've got no traction to brake.

In my opinion, turning harder is usually the best choice. At least then there's a chance to make the corner. At worst, you'll lowside.

Of course, there are always other options. Often, it's possible to recover at the cost of the drive at corner exit. Expert drivers may recover by sliding their rear for little more turn in.

Dave has some considerable experience with what he's speaking of...slowing the bike INSTEAD of steering/ adding lean angle. There does come a choice when one has to throw it in, but that's not at this point...we're still in the braking zone, or have overshot it.

 

[Burning1]

Holeshot, I agree with you on a lot of your points, but it sounds like everyone might benefit from some clarification here.

Some of this discussion applies to street riding, some to novice track riders, and some to racers. The first two groups should always keep some lean angle in reserve. I agree with you that that the latter group never will.

I don't believe Archimedes was suggesting that you should add extra throttle and lean angle once the bike is mid turn. It sounds like he was referring to a roll on of the throttle during turn-in at corner entrance.

If my memory is correct, this is basically what Keith Code recommends in a Twist of the Wrist 2.

 

[Zachary]

errr

So, if I have something wrong, please let me know, but the further down you are leaning, the less traction you have. If you are in full lean and hit the throttle, your chances of sliding are greater, because you are on less tire. As you come up, you are grabbing more and more available traction, which is why you should steadily increase speed as you come up yeah?

 

[Enchanter]

Retentive type ain't ya. My meaning was, from the point you get back on the throttle. As a non-trail braker, that would be right after I heel it over to full lean. Yes, for a trail braker that would be the point at which you get back on the throttle.

Lay off the insults. Seriously.

My point is that if you are going to give advice, you better be damn clear when you give it. Your words and your intent seem to be in conflict with each other.

 

[Burning1]

So, if I have something wrong, please let me know, but the further down you are leaning, the less traction you have. If you are in full lean and hit the throttle, your chances of sliding are greater, because you are on less tire. As you come up, you are grabbing more and more available traction, which is why you should steadily increase speed as you come up yeah?

Read my earlier response about shifting the weight balance and keep in mind the difference between accelerating for traction, and accelerating for speed.

A small amount of acceleration will help to balance the bike, and will smooth out the road. Accelerating does use some rear wheel traction, however having the correct weight balance provides a net benefit overall.

Any acceleration past what's required to balance the bike will reduce available traction. As the lean angles decrease, more traction is available for extra acceleration.

We apply the balancing acceleration before we reach maximum lean angle because adding throttle demands extra traction.

 

[Burning1]

Dave has some considerable experience with what he's speaking of...slowing the bike INSTEAD of steering/ adding lean angle. There does come a choice when one has to throw it in, but that's not at this point...we're still in the braking zone, or have overshot it.

Good point. Re-reading Dave's suggestion, he was obviously advocating trail braking into the corner when the rider feels like he's about to enter too hot. My comment applied to a slightly different situation.

 

[Holeshot]

I'm not sure what balancing accelration is and I'm not sure why one would be adding lean angle AND throttle at the same time. What works on the track works on the street. There is no difference, minus the safety reserve we should all keep when on the street.

 

[Burning1]

Holeshot, you agree with me that gentle/smooth acceleration is a part of proper cornering technique, correct?

If so, where do you recommend that we begin our acceleration?

- At corner entrance before the bike is leaned over?
- After we reach maximum lean angle?

 

[Holeshot]

After maximum lean angle, as you're picking the bike up onto the tire.

 

[Burning1]

After maximum lean angle, as you're picking the bike up onto the tire.

So, do you advocate:

- Coasting through the corner with the clutch in?
- Allowing engine braking to slow the bike?
- Maintaining constant speed with gentle use of the throttle?

 

[tzrider]

The discussion seems off on a tangent from crash analysis. There are a few points I'm tempted to respond to, but is this the place?

 

[Burning1]

The discussion seems off on a tangent from crash analysis. There are a few points I'm tempted to respond to, but is this the place?

It's not really the place, but it's very hard to get a conversation re-started once it's been moved to a new thread. Mods?

 

[stangmx13]

The problem is that if you've truly committed to the turn too hot, braking will cause you to crash instantly. If you have enough traction to brake, you've got plenty of traction to turn. If you've got no traction to turn, you've got no traction to brake.

i never thought about it that way......

 

[Holeshot]

It's not crash analysis, but go ahead Andy...we can move the thread if we need to, to the training forum...but it'd be stuipid to not hear your advice. you've got some excellent knowledge.

 

[Holeshot]

Burning1: depends on the turn I suppose. Some turns have me trail braking up to the apex, other's are an early apex with heavy throttle, others are maintence throttle with a rolloff midturn and added steering, and then heavy throttle...

No size fits all. There are different techniques for different turns...that may be part of your problem...

 

[tzrider]

This thread has pulled in a number of ideas on throttle use and turning, which may relate back to the OP's incident in some way. The questions that have emerged that I have an opinion about are:

1) What should a rider be doing with the throttle in a corner?
2) Does a bike turn via leaning or steering?
3) Why doesn't Keith Code teach trailbraking?

The answers to many riding questions can depend on what the rider is trying to do in a given spot. The situation the rider is in will play a role; e.g. a severe downhill approach to a decreasing radius turn may call for different uses of throttle and brakes in different parts of the turn than you'd use in a flat, on camber 90 degree turn.

Keith Code's Superbike School is a program that, among other things, teaches the rider how to get the best handling and traction out of his bike. The bike delivers the most traction that it is capable of under light acceleration. This distributes weight in proportion to contact patch size and places the suspension in the middle third of travel, where it works best. The program at CSS is oriented around tactics and control operations that serve this goal.

Trailbraking falls outside of this scope. This is not a criticism of the technique; it has valid applications. But it's not a technique that makes the bike work at its best. It's a technique that deviates from optimum handling and traction to serve another purpose that may be more important in that situation. Passing on the brakes is the obvious example. Working DR turns can be another.

A rider is best prepared to deviate from optimum conditions after he has mastered producing optimum conditions. In terms of outright speed, if a rider is four seconds off the pace in his class, he has more to gain from working on his throttle control than he does from braking deeper. That's not to say there's nothing for him to gain from later braking, but the big gains aren't found there and the rider may adversely affect his lap times if he doesn't approach his braking in a disciplined manner.

In terms of racecraft and gaining positions, braking is crucial. But riders who can get the most out of the bike in ideal conditions will get more out of actions that deliberately depart from ideal. Keith understands deep, late braking and teaches these skills in the Code R.A.C.E. program.

The framework I apply to street riding in normal circumstances is to use the techniques that get the best handling and traction out of my bike. With that in mind, whenever possible, I make a single steering input per turn to put the bike on a line that allows proper throttle control. To me, proper TC is cracking the gas on as soon as I set the lean angle and gradually rolling on through the turn. My roll-on begins long before the apex.

On the matter of whether a bike turns due to leaning or steering, I was surprised to read Holeshot's assertion it's the latter. A turning motorcycle is a complex thing; harder to understand than a car, I think. We can take isolated examples to highlight certain aspects of it, but a number of things work together and they sometimes seem to contradict. I'll see if I can explain my own understanding.

First of all, a motorcycle cannot turn without leaning. At the very least, leaning is necessary to keep cornering grip and centrifugal force in equilibrium. The question is, does leaning actually cause the bike to turn?

If you take a tire, lean it over 20 degrees and set it to rolling, it turns. That seems to imply a motorcycle would too. OTOH, when riding a motorcycle slowly, it's dead obvious you have to point the front wheel into the arc when you're turning. These ideas seem to conflict, but to me they reconcile pretty well.

When you turn a bike, it (or you) must lean. Whether you lean with the bike or against it, the combined center of mass of you+bike will be inside the arc the tires are traveling on. Turns on motorcycles are *always* initiated by leaning the bike, however it is you do that. And if you're going around a turn with the bike vertical, you're leaning your body to the inside. There's no getting around it.

Once the lean is initiated, the front tire does have to point into the arc. It must do so in order that both tires can follow the same arc. You wouldn't be able to expect the front and rear tire to track an arc if they were aligned on a vector. They must be aligned on the arc.

When riders initiate turns slowly, it can be difficult to determine whether the bike leans before the front wheel must turn into the arc or not. If you initiate a turn very quickly, you can easily tell that the lean angle sets first and the front wheel must then turn in to follow the arc.

 

[Burning1]

No size fits all. There are different techniques for different turns...

But there are also guidelines that can be applied to most corners. I assert that in most cases, it's best to accelerate gently through a turn, and a lot of smart people concur.

You seem to be focusing more on the exceptions than you are on the rule. I think it's important to be clear; they are exceptions. Now, I do believe there is huge value in knowing the exceptions and I appreciate that you are giving your input on them. After all, a rider that doesn't know to let off the throttle in order to change their lines might struggle with my advise.

that may be part of your problem...

There is still so much to be discovered about motorcycling. Our knowledge of the sport has grown by leaps and bounds over the last 30 years and shows little sign of slowing down. You could discount every bit of knowledge that you disagree with or don't understand, but I think you'd miss out on a lot in the coming years.

 

[Holeshot]

Andy, thanks for chiming in man! To be clear, leaning the bike is not what steers the bike, nor changes the bike's direction...as you said, the tire turning into the turn is what actually steers the bike. When novice riders try to add more lean angle, but then resist the front tire steering into the turn (by keeping a stiff inner arm...and not using their legs to hang onto the bike), the bike does not steer and instead, continues to run wide...and they haven't tightened their line nor affected their arc in any significant manner. So, we kind of agree here...certainly the headstock is the pivot point for all the mechanics of the motorcycle steering. It's always that argument of body steering VS countersteering, but the truth is, both are happening.


Burning1, I do have some decent experience with the concepts we're speaking of. I've done all kinds of stupid moves and some quite heroic stuff at times that made little sense until I analyzed them further. I'm not sure who these "smart" people are that concur on some fairly loosely defined concept...but those I know and trust, we break down a turn into parts and figure out what we want from the turn and why. Explain how one gently accelerates through T7 at Sears, through T14 at Thill , T11 at Laguna, or T6 at Miller Motorsports. I'd argue if you do so, I'll beat you evertime on the exit, or at least part way down the adjoining straight. These aren't exceptions...they're just the landscape we call "riding".

I'd say this: there's much for ALL of us to discover riding. I believe newer riders with more book knowledge than riding experience should work on discovering what techniques work and which do not, for them in a riding situation. I think the track is calling you!

 

[tzrider]

Andy, thanks for chiming in man! To be clear, leaning the bike is not what steers the bike, nor changes the bike's direction...as you said, the tire turning into the turn is what actually steers the bike. When novice riders try to add more lean angle, but then resist the front tire steering into the turn (by keeping a stiff inner arm...and not using their legs to hang onto the bike), the bike does not steer and instead, continues to run wide...and they haven't tightened their line nor affected their arc in any significant manner. So, we kind of agree here...certainly the headstock is the pivot point for all the mechanics of the motorcycle steering. It's always that argument of body steering VS countersteering, but the truth is, both are happening.

Sure thing. Always fun to kick this stuff around.

We're not yet saying the same thing about cause and effect of getting the bike to turn. I do feel it's the lean angle that defines the arc. You are, however, correct that the rider who straight-arms the inside bar often goes wide of where he wants to be. The next time you see someone doing that, check out their body position. Their torso won't be lined up with the bike; it'll be crossed up. In short, they're not hanging the heaviest part of their body off. If they bend the inside elbow, their body must lean to the inside of the turn. They will naturally hang off more, effectively increasing the lean angle (not of the bike, but of the bike+rider). This alone will tighten the arc.

If the rider were literally leaning on the inside bar so much it points the front tire to the outside of the arc, the bike would countersteer to a deeper lean angle. We do agree that in a turn, the front tire will be pointing into the arc. If I understand you right, you're saying it turns the bike, much the way a car's front tire would. I'm saying the lean angle produces the arc (like rolling a bare tire leaned over results in an arc) and the front points into the arc because it must. If it points a little to the inside of the arc, the bike will stand up; if it points outside the arc the bike will lean deeper.

Over...

 

[Holeshot]

I'd argue that far too many novices focus on the lean angle and don't understand it's significance...that's why I argue it's not the lean angle which dictates the arc, it's the stabilizing front wheel pointing into the turn that determines that. If we want to add steering mid turn, we don't need to add more lean angle, we simply need to add more weight to the inside...forcing the front wheel to steer more into the turn to stabilize the bike. On a bike with a front wheel that does not turn, adding lean angle would only cause the bike to lean over...not change direction/ arc.

Lean angle essentially forces a bike's front tire to steer into a turn...as we go quicker in a particular corner, more lean angle is need to counterbalance the gravitational torque on the bike. We drop our weight down low and to the inside to counterbalance this force. Lean angle is essential because it allows the most beneficial direction of a counterbalancing force. I'd argue that bike's can steer just fine without lean angle, only without some counterbalancing force, they'll flip onto their sides on the outside of any given turn. The lean angle does little more than provide counterbalancing forces to the gravitational torque of a motorcycle. The front wheel, same as in an auto, performs the actual steering.

We can see this with countersteering...countersteering (wheel pointing away from a turn) allows the chassis to pivot around it's axis and begin the lean of the motorcycle. However, the bike is not changing direction, nor steering, until the wheel then points into the turn. Most new riders believe it's beneficial to add more steering by adding more lean angle (countersteering mid turn), yet the lack the finesse to allow the front wheel to point back into the turn after adding said lean angle...and they straight arm the bars until they run out traction. We can do the same thing by loosening our arms, putting more weight down low and inside and weighting the inside peg. The bike increase it's front wheel steering to counterbalancing the "falling over" effect and we have changed the amount of steering without concentrating on changing the lean angle.

Lean angle, to me, is not the thing to concentrate on. It's a symptom, not a technique....