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jcw

timing of steering input and chassis attitude

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At a recent trackday, one of the coaches was leading a classroom session and was describing the bikes "attitude" on and off throttle.

My impression of what he was saying was that the bike is always slightly pitched back on acceleration or pitched forward off throttle or on the brakes. And your goal is to minimize coasting.

 

So, it got me to thinking about the timing of steering input and this chassis attitude. I know that weight shift forward will change your geometry to decrease rake and trail and possibly make it easier to get the bike turned. My question is, is this the goal in every corner? How much effect does this on/off throttle exactly have on that initial steering? Do you look to pitch the bike forward slightly and time your steering input during this time to get the most response from the steering input? Obviously you aren't going to jam on the brakes and countersteer your hardest.

 

I was noticing significant resistance to turning going into a couple corners at my last trackday. Turn 1 at autobahn cc north is a short left kink after the front straight where I make about 125mph and at T3 after a short short straight at about 75? I've made changes to my body position since that last trackday, getting closer on the tank when practicing on the street but have yet to try it out on track. Just with this simple experimentation it is obvious that a higher center of gravity noticeably slows your ability to lean and transition the bike. It has not been as clear to me whether timing the countersteering input with weight shift forward is as helpful but this is on the street where I'm building in a much greater safety margin.

 

I ride a 11 gsxr750 with shimmed rear shock. And I have the ability to play with the fork offset if needed. I was thinking about this but wanting input on whether I could improve turn in with riding technique before I further mess with the chassis settings.

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Most likely the coach at the track day was trying to help riders avoid the common error of braking (which compresses the forks) then releasing the brakes (which allows them to extend again) then turning the bike (which compresses them again). This bouncing up and down is, as you can imagine, counterproductive to accurate and predictable steering. In a simple corner the ideal scene is to be coming off the brakes as you are turning the bike, so the forces transfer from the deceleration forces to the cornering forces and keep the forks compressed instead of popping up and back down again.

As far as telling you how exactly how much effect that is going to have, it is not realistic to think anyone can do that for you, there are far too many variables (suspension setup, rider and bike weight, braking style, steering input rate, surface traction, shape of turn, and so forth). You will have to experiment with it yourself, on your own bike and observe it. Almost certainly YES you can improve it with riding technique (have you been to school and had the Hook Turn material yet? Or the slow brake release classroom session?), unless your front suspension is extremely stiff in compression or has rebound damping set excessively low.

Definitely you can sharpen up the steering on a bike by lowering the front a bit, but if taken too far this can compromise stability and you can get headshake, or twitchiness in the steering. Not sure the GSXR750 would need much changing on geometry, though, my impression of those were that they had nice handling.

In the specific turns you describe (T1 and T3), are you trying to turn the bike while still on the gas? For sure that will make it harder to steer. Are you ABLE to steer it now and just noticing the amount of effort required, or are you running wider than you want in those turns?

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Thanks for the reply.

I have not done the school yet and know of some of the drills through second hand descriptions only. I have used the hook turn technique as i understand it and do see the usefulness of it.

 

I take T1 on a neutral throttle slowing a bit, i know the really fast guys are just flying through here using engine braking only. Ive definitely slowed down on brakes before this. But its the fastest "turn" im negotiating.

T3, just coming off throttle after accelerating down the short chute.

I have trouble pulling the bike down to the apex is probably the best description i feel. Maybe its my fear or inability to lean the bike far enough when going fast(er).

 

I go back in two weeks and wanted to have something to try. I asked a coach and they told me to take it in a higher gear.

But, good to know that for a simple corner the best way around is gradually trading lean angle with braking. How does this apply to the quick turn or quick flip turns?

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3 hours ago, jcw said:

........But, good to know that for a simple corner the best way around is gradually trading lean angle with braking. How does this apply to the quick turn or quick flip turns?

Basically, the same two processes happen simultaneously, only that in a shorter period of time than for a lazy turn.

The front suspension and tire are loaded because deceleration, then that load caused by deceleration gradually yields as the load caused by the circular trajectory of quick-flick and tracing the curve rapidly increases (up to lower or similar value).

You can find additional discussion about the quick-flick technique here:

 http://forums.superbikeschool.com/topic/4101-can-quick-turn-be-overdone/

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4 hours ago, jcw said:

 

I have trouble pulling the bike down to the apex is probably the best description i feel. Maybe its my fear or inability to lean the bike far enough when going fast(er).

 

"Pulling the bike down to the apex" is an interesting description. What EXACTLY are you doing, physically, to get the bike to turn?

For sure it is harder to turn the bike at higher speeds, and also harder when you are on the gas. By "harder" I mean more actual physical effort. What must you do, EXACTLY, to change your steering input to deal with that additional effort?

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Right, so ive been working on my body position not to hang off so much but positioning myself to make effective input for countersteering at the bars.

Ive read about the technique of pushing the inside bar and bracing with the opposite (outside) leg. And the wall example. I need to remember to do this more as i believe i tend to steer with both hands and from both feet or my butt.

Hopefully this will make the difference when i get back to the track this time.

 

The pulling the bike down to the apex might be my residual desire to body steer the bike into the lean which obviously is not doing the job...

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Pivot steering. That's what it was called. Found it in the linked thread from Lnewqban. Thanks

 

Where was it that I read that steering with one hand is more accurate for most people than steering with both hand? Was it CSS?

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OK, got all of that. Good that you are putting your focus on countersteering to get the bike turned effectively, and pivot steer is a very good technique for that.

So, if you are going into a turn with a lot of speed, and maybe are on the gas also, it will for sure take some effort to turn the bike. If you wanted to turn the bike more quickly, to make it to your apex, would you have to push on the bar FASTER, or HARDER?

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I've seen you state the input at the bar is harder not faster but I'm not sure how that differs.

If you push harder, doesn't that move the bars faster? Pushing harder means a greater force at the bar which in turn turns the bar faster. Not sure how you have one without the other. I must be missing the subtlety of the difference you are trying to convey.

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Some riders, when learning about quick turn, think a rapid steering change is accomplished with a quick jab at the bars. Sometimes that quick jab does not have enough force to turn the bike quickly at speed, sometimes it is too roughly applied and upsets the bike, sometimes the rider does not (when trying to "punch" the bar") hold the pressure long enough to achieve the desired lean angle.

Bear with me, I am just asking some questions to explore your understanding of various techniques, to see if anything comes to light that will solve your challenges through the turns you describe.

You mentioned a "fear or inability to lean the bike far enough when going fast(er)". I'm going to fire some questions at you and let's see what comes up:

Do you have a concern about traction?

Are you concerned about ground clearance?

Are you comfortable that you know how much you want/need to lean the bike to get to the apex in T1, for example? 

Do you know how to stop the bike from leaning over any farther once you get the desired lean angle?

How much visual information do you have before you turn the bike? Do you have an apex chosen, and do you look at it early enough before you steer the bike to have certainty in your steering input?

If you roll off the gas or go flat on it, are you finished steering the bike before you roll back on?

I am not discounting the idea that there could be things that could be done, mechanically, to the bike to make steering it through those turns easier, however you asked about techniques that could improve things so that is why I am exploring to figure out what you are doing now, and if there are things that could be changed to help you get to the apex on these turns... without having to slow down too much. :)

 

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Yes, I've crashed three times in one and a half years and the second one fractured my clavicle. Good thing I'm stupid and stubborn and I keep coming back for more. But I've almost got a decent degree of confidence back. Traction concerns are more imagined than real, I think. One crash was my first time on a soaking wet track and I was on DOT supercorsas, another me and another bike decided to occupy the same space at the same time going into a corner. My fault. My confidence was sapped for a while.

No concerns with clearance. I've set up the bike with some good rearsets and the bike can lean farther than I dare. I'm nowhere close to dragging a foot or a knee for that matter. Here's a random pic of me on my first trackday this year. I don't think I've progressed much from this.

autobahn.jpg.7df32a7b57a69ce5fe1caa0f75a05db4.jpg

 

20.jpg

 

I think I know how much lean I need, it's the effort to turn that seems excessive. But at the same time, I know I'm your typical not-so-serious beginner/intermediate trackrider and know I'm not REALLY hitting a deep apex.

 

Right, so to stop leaning, you ease up on the countersteering pressure at the bars. The steering should fall in line and then follow the corner.

 

Vision is something I always need to remind myself to maintain. Even though I've ridden this track for last 8 years (usually only once a year until last couple), I haven't really been serious about going fast until last 2 years.

 

I struggle with getting on the throttle early enough. So, I think I'm for sure done with steering before getting back on the gas. It's another thing I'm working on.

 

Thanks for the directions, I'm seeing what I may need to work on and will figure a plan of attack for my next trackday in a couple weeks.

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On 8/16/2018 at 10:12 PM, jcw said:

Pivot steering. That's what it was called. Found it in the linked thread from Lnewqban. Thanks

 

Where was it that I read that steering with one hand is more accurate for most people than steering with both hand? Was it CSS?

I believe that the only reason for steering to be less accurate is a survival reaction of one hand fighting the other.

That does not mean that we should reduce or eliminate the steering torque produced by one of the hands, but that we should observe that potential SR.

Your bike my have a under-steering tendency, due to geometry or tires or tire's pressure.

I would experiment with lowering the front end some and/or raising the rear end, in order to reduce the trail of the steering some.

That would reduce the tendency of the steering to remain on a straight trajectory.

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MaxMcAllister in his suspension clinic (can be found on YouTube) provides the info that all geometry changes have a side effect for every intended effect. He said it’s about 3:1 ratio of effect to side effect and many people chase setup issues because of missing information of knowing which end of the motorcycle to change.

The cliff notes: he provides that front end changes effect corner entry to mid turn and rear end height changes effect mid turn to corner exit; being mindful of the side effect issue.

My concern with prescribing a geometry change at this point is introducing another variable into the equation when rider input, vision, timing and throttle control haven’t been sorted, nor do we know if static sag and chassis balance have been baselined.

My $.03 is aligned with the OP and Hotfoot’s process to establish what the rider is doing and how the bike is responding.

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I'll check back in after my next trackday.

Follow up---

Trackday was almost washed out. I got in 1 good session and a wet one and just called it a day...

I was only able to work on one thing and that was really focusing on getting a good base with the outside leg to pivot steer with the inside arm. And man was it effective! I was able to notice improved steering input speed/force(whichever is correct) and accuracy even after that one dry session.

One of the side effects, though, was that I ended up more centered on the bike by mid corner and wasn't "hanging off" as much meaning I think I was carrying more lean angle. (my tires were more clean to the edge after my only dry session)

I did a bad thing and played with the triple offset reducing it 1mm before the trackday as well. The difference was immediately noticeable and I let myself have several street riding days to get used to it before the trackday.

I did also work on getting on the throttle as soon as I released countersteering pressure on the bars. And then focus on when I could trade lean for throttle. Found out this really mean using your vision effectively to pick out the correct exit line that lets you do this.

After the trackday, I happened to read something on early apexing that made so much sense. Beginners like me will tend to turn in early thinking it's the safer line. You might even rush a corner with more entry speed because you think it's safer. But all it does is run you out of corner on the exit. It really made sense to me WHY i was having those pucker moments when I find myself on a line that was going to be too wide on exit.
 

Edited by jcw
Follow up...

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On 8/16/2018 at 8:33 PM, Hotfoot said:

Most likely the coach at the track day was trying to help riders avoid the common error of braking (which compresses the forks) then releasing the brakes (which allows them to extend again) then turning the bike (which compresses them again). This bouncing up and down is, as you can imagine, counterproductive to accurate and predictable steering. In a simple corner the ideal scene is to be coming off the brakes as you are turning the bike, so the forces transfer from the deceleration forces to the cornering forces and keep the forks compressed instead of popping up and back down again.

 

That filled in information that was missing for me when trying to understand why I had so much difficulty adapting to the early braking-before-turning way of riding after always trail-braking more or less to the apex. In the end, I wound up with a compromise just the way you described it above, but thought it was just me not being able to properly adapt to the "proper way" of turning in. Now I feel much better - thanks ☺️

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Regarding ease of steering: you can push the inside bar (push right bar to go right...) but you can and should also pull the opposite bar. Some people have a hard time coordinating this if they have not done so before.

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It's what I've been doing instinctively since I first began riding in 1980, and I find it difficult to  push - or pull - only. I believe I did it like that from day one because it must have felt balanced when riding ultra-light 100cc streetbikes of the day; with no place to really anchor oneself against the forces going through the handlebars, pushing and pulling - albeit gentle - would ensure a fair balance of forces reaching the body. 

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On 11/25/2018 at 9:37 PM, Dylan Code said:

Regarding ease of steering: you can push the inside bar (push right bar to go right...) but you can and should also pull the opposite bar. Some people have a hard time coordinating this if they have not done so before.

How much awkwardness have you seen from students trying to change their techniques to push-pull with both? How long does it take for this to become habit in the average rider?

Otherwise, I would think this could consume valuable mental processing capacity until it becomes second nature.

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On 11/25/2018 at 8:37 PM, Dylan Code said:

Regarding ease of steering: you can push the inside bar (push right bar to go right...) but you can and should also pull the opposite bar. Some people have a hard time coordinating this if they have not done so before.

Dylan, I have only found fleeting statements in TOTW where Keith writes that one can use pulling of the bar when steering. Can you expound a little on the topic?  Is there a need to become skilled at push-pull steering, particularly if pivot steering is working well?

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I think this topic is simple enough to where someone can just go out and try it. In my experience I have seen every combination of rider with regard to preference on bar pressure but it does make sense that using both a push and a pull will give the most control.

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No, instead of going to try it (and besides it's in the 30dF temperature range here) we'd rather discuss it ad-nauseum online until the thread is at least 500 posts. LoL

(point taken, Dylan)

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You must believe me when I say that I was extremely cautious before asking about this, painfully aware of how the topic of steering has generated an infinite volume of counterproductive babble.

Jaybird, I do have potential riding conditions. I might even test this today.   :)

I have tried the push-pull method. In my initial attempts I inadvertently generated excessive grip/tension in the pulling hand. I find that feeling the pressure of pulling on the throttle was particularly disconcerting and made me question if I was altering the throttle (I do not think I was, I think it was a mental block, but I also shudder to think of potential problems that I may generate with the more sensitive throttle on a race replica.) Also, I read all of Hotfoot's advice with enthusiasm and she provided this: 

http://forums.superbikeschool.com/topic/2856-countersteering-push-or-pull/

"Having said that, I try to use only pushing when riding hard on the track, because I can get a more consistent input using a push with pivot steering. If I try to pull, I am more inclined to yank on the bar and get a bit of a wobble at the end of the input."

14 hours ago, Dylan Code said:

...it does make sense that using both a push and a pool [sic] will give the most control.

Admittedly somewhat uninitiated, but with the above input so far, it seems counterintuitive to me that one would steer more accurately by introducing two hands into the process that a single hand could otherwise accomplish.

It is most helpful for me to hang onto what you said Dylan, that you have witnessed every combination of how riders address bar pressure.

 

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Riding with one hand forces the rider to both push and pull on the bar...

The push is in my opinion more accurate but the pull can help overcome the resistance for higher speed turns.

Less necessary for a light responsive bike. 

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