My conclusions about "Hayabusa can't corner" and the track riding poll

IG. said:
Now, there could be a couple of different scenarious where a rider makes a mistake leading to a possible highside.
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Almost all single bike crashes are due to the rider making a mistake. The bike won't crash on it's own, you must force it to crash.

Something to think about is: the faster you become the smaller the margin of error becomes. At a leisurely pace, you can use whatever gear you desire and you most likely won't spin the rear. It's when your buddy is out front and pulling away when you toss good judgment and common sense out the window and decide you'll pass him in the next corner that you may want to remember to keep the rpm's up through the corner? :beerchug:
 
raydog said:
I certainly would not speak for Mr. Bogus but I must agree with the general rule that....the higher the rpm-the lower the potential for highsiding. And yes, that makes you closer to the rev limiter and occasionally I'll hit it but so what? Hitting it only occurs AFTER the apex on the way to full vertical with more forward traction and it only occurs occasionally. It is quickly made irrelevant by an upshift.
As to spinning the rear when not intended (rain, liquid on track, etc.) I've stepped out a few times but a quick roll back of the throttle before the regaining of traction eliminates the forthcoming high side.
There's one aspect no one's mentioned yet, that is, the riders judgement, feel, connection to the motorcycle and track. There is a more esoteric component past the science...it just comes from 1000's of laps, previous mistakes, the way you are hard-wired personally as a motorcyclist. Some are happy to "just ride" while others must explore their "limits". Actually, it's a continium and I, for example, like to explore BUT MUST INCLUDE a great deal of personal safety (two college bound daughters, house, wife, you all know the story). I just know my DNA won't allow me to pull a trailer on a Gold Wing but commands me to enjoy the more extreme ends of our sport....and enjoyment it is! I know that's true for a lot of you as well and I truly enjoy reading your take on it all. Peace, Doyle
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says it for me :) one other caveat here...

Racing: although it is only a track day... I know my lap times are quicker when I can pin the throttle OPEN... I see no flaw in the technique at this point.. I know the bike accelerates harder from 8000-11000 than it does from 6000-9000 rpm..

I do not think it is a bandaid or covering bad technique by keeping the motor in the top of the powerband.. Seems to be a better technique IMO..

Now I wish I had the thousands of laps of experience... only my first year of track riding , but boy am I having fun and learning a lot...
 
Poor judgement is bad all around. No doubt about that. Don't have buddies, ride solo - street or track.

I am still trying to get to the bottom of the tire spinning issue, and the more I think about it, the more I am convinced that the rider doesn't have to be in too high rpm. To be specific, I think for the Busa staying within 6k - 9k is just fine, and starting to spin the rear while being at 8k is as safe as starting to spin the rear being at 10k. And the correct way to do it is as I mentioned above - rolling it on smoothly, and simply stop rolling on when the rear breaks lose.

Just looked up TOTW 2 to see what Code has to say on the subject, and he actually advises to chose the tallest gear possible which will do the job of getting through the turn without redlining at the exit - it's common sense to avoid being forced into an upshift at the exit when you need to be hard on the gas. Let's say a rider enters a turn at 60 mph and reaches 80 mph on the exit close to redline of 11k - a reasonable example. A quick equation, and the engine speed at 60 mph should be 11k/80*60=8.25k. So, being around 8k is a reasonable thing to do. But there is no time to figure it all out when you ride, so a rider might chose a gear which at 60 mph at the entrance makes the engine turn let's say at 6.5k. Doing similar math, and at 80 mph on the exit, the engine would spin at 6.5k/60*80=8.7k - this is almost 9k rpm where Busa makes plenty of torque.

Based on the responses I am getting, I think there is a bit of confusion as what I am trying to figure out. I am less interested in what happens when a rider makes a mistake as opposed to what is the right way of doing something. I want to understand and comprehend the correct and logical way of doing something - from various angles, later on visualize it and practice in my mind - program the correct actions and reflexes in my mind - and only then go out and possibly try it.

I completely agree that if a rider wants to catch his buddy and opens the throttle abruptly at the exit causing the rear to spin, the higher rpm may save the rider if the rev limiter kicks in, thus covering for his mistake. And if such rider was in pretty low rpm at the entrance, let's say 4k, he will be tempted to go WOT and maybe for a moment he will be OK, but when the torque kicks in and the rear breaks lose, there isn't much that can be done to save it - he overstepped the traction by a huge margin.

I however would not use a rev limiter as my standard technique to control the spin, but rather lely on smoothness of my throttle hand to assure that the rear tire overstepped the traction threshold by 1% and not by 50%.

Code made an interesting point. Another way to get out (or take advantage) of the spinning rear is to start straightening the bike by turning the front slightly to the inside of the turn - pretty much how one would normally start straightening the bike. The bike being more upright will cause the rear to hook up quicker. Actually, as I typed this I realized that since we are talking about exiting the turn this is being done by the rider anyway. But, if in the middle of a turn and the rear broke lose, slightly straightening the bike while holding the throttle steady would do the trick.

The whole spinning the rear thing is done by exceeding the limits of traction by a small margin. That's the key!

EDIT: while I was typing my response, Mr Bogus was typing his... Not sure how lap times got into this as I don't really care for lap times. I ride on the track and street about the same, except it's less of everything on the street. So, the point is I am SIMPLY ENJOYING AN AGGRESSIVE RIDING, and getting in the zone to maximize the pleasure and joy of riding is the objective of this entire exercise, at least to me. That is why I don't have to squeese every pony out of this bike and stay in the highest rpm possible. It still happens occasionally, and I get close to redline now and then.
 
Throughout this whole thread I don't recall anyone explaining on thing about why racers recommend the top 25% of the engines RPM range. It's not just about the rev limiter keeping a lid on everything. Most motorcycles produce less torque in the top 25% than they do in the 50-75% range. For and example, the Busa generally produces the most torque in the 5-8k RPM range, giving it more potential to spin the rear tire than if it was running at a higher RPM range with less usable torque. (See attached picture.)

Throttle control on any high-power bike is an essential skill to learn. Every bike is different. The rev limiter will help reduce the amount of spin-up if the rider does make the mistake of too much throttle.

After doing a few track days, at a performance riding school, I have learned two important skills. First, my lines through long corners used to suck. This is something I still work hard to keep on track. Second, running both the Busa and 1K in the top 25% of the RPM range resulted in faster and safer laps. My first few laps on Pacific Raceways I was running every corner but one, turn 10, in 2nd or 3rd gear. The racers and instructors kept telling me I needed to use a lower gear on most of those corners. When I applied what was being said I started getting faster lap times, and the bikes feel more stable during the corner.

As a result of the local riding school and local racers, including Tuffbusa, I have determined that are a general rule of track riding. Below are the gears that I use for each speed in the corners with factory gearing.

0-75: 1st
75-120: 2nd
120+: 3rd

08BusaDyno.jpg
 
OK. I see what you are saying. But again, for some reason it goes back to lap times. The argument about having a higher torque in the middle of rev range doesn't make a lot of sense to me. First, the chart doesn't show rpm, so I am assuming it's 1k per unit. So, the chart shows a redline at 13,5k. I thought it was 11k.

But anyway, so what if I exit a turn with torque of 105 ft lb at 9k rpm vs. 100 ft lb at 10.5k rpm according to the chart? I don't see a significant difference in torque between 105 ft lb and 100 ft lb. And if the objective is to reduce torque at the exit, then why not drastically reduce rpm? Let's see, if I exit at 4k - 5k rpm range, according to the chart above, the torque would be slightly above 90 ft lb! All the torque mentioned above is within 90 - 105 ft lb - still pretty high any way you look at it. So, the key to safe riding is not in playing with torque.

I am still not getting a clear answer as to why "I am yet to highside" if I use 6k - 9k rpm range as opposed to 8k - 11k rpm range.

I did miss a couple of things in the past which could've prevented a couple get offs. One was not replacing my damper fluid with a thicker one, even though I read about it, but sort of dismissed. A really bad tankslapper caused a crash on the track. Another one was when I neglected to notice glazing of my brake pads, again generally being aware of such condition.

So, when someone tells me that I am yet to highside because I don't keep my rpm at the highest level, I start questioning myself and trying to figure out what if any I am doing wrong. Again, so far I can't get a satisfactory explanation.
 
The thing is that a spinning rear will step out as it spins up in some relation to how much faster the rear is turning vs. the front is turning, so if you only have say 20% or your rev's left, the rear won't step out as far as say you have 50% of your rev's left when the tire breaks loose. I never highsided a street bike but I've had major step outs. I did practice my highside on motorcrossers until i got it right :whistle: If you want to practice, try hitting mud under leaves on turns, having tire lube on your rubber when you hit the street, too low of tire pressure, cold tires, etc. the physics are constant, bike steps out (power slide) - if it goes too far the bike gets sideways, lowside. /else you panic & correct the bike smaps back triggering either an impressive death wobble & save, or generally equally entertaining highside. just from my experience, have not tried to duplicate on the busa :laugh:
 
I agree. But you are describing a rider's mistake of gunning the throttle, and the rev limiter saving the day. I don't do that.

The key is to gently exceed the limit of traction by rolling the throttle ON smoothly and slowly, as opposed to abruptly. And that's what I've been doing all along with no ill effects - street or track. Actually, before you are about to break lose, the tire will "tell" the rider assuming the rider is "listening". I didn't have too many cases of the rear braking lose, but I did go through some fine gravel (very slight lean - almost upright), and I remember another time hitting some branches/debris right in the middle of the turn and the rear definitely stepped out, but hooked up very gently. Oh, there was a poor small animal which I sent to Haven, but there was nothing I could do - I was committed and he was right on my line - sorry little guy.

There is also a negative effect of high rpm. The excessive engine vibration at high rpm partially masks the feedback from the tire. As a result, the rider will not know the rear is about to break lose and keep rolling the throttle on until the full slide.

Someone in this thread described someting similar happening to him - something along the lines that others saw his rear shredding rubber or sliding a bit while the rider felt nothing unusual. I'd venture to guess that the engine vibration at high rpm partially masked a valuable tire feedback.

So, all-in-all, my approach to rear wheel slide was this: ignore it as if it is not happening - freeze that right hand and don't move it. That worked well over time.
 
chose the tallest gear possible which will do the job of getting through the turn without redlining at the exit
Click to expand...
covers the entire subject.. and for the sake of the discussion, we are talking about "track riding" at 90% or better

you do not want to be upshifting at the exit.. bike should already be on the ragged edge, shifting would upset this critical moment in time
IF you spin the rear tire, it will hit the rev limiter, you are going to hopefully have a warm tire with a predictable drift..

Why are you not spinning the rear tire? maybe you are going too slow? and before anyone jumps on this..

A tire has a finite amount of traction.. if that traction is used for braking, accelerating or turning, it has a limit.. (I am sure I read this in TOTW as well)

if you barrel into a corner at 99% of a tires traction, you have a 1% margin of error.. could be braking, accelerating, turning, regardless, you got 1% of the tires ability to hold left.. it might take 4hp to use up that 1%

Same corner at 75% of tires ability to hold.. now you have a gigantic margin of error to deal with.. you can screw up the braking, acceleration or lean angle by a good margin and return without any scratches..

It is not going to make much difference what gear you are in if the bike just can not physically overcome that 25% traction reserve..

try that same stunt with 1% in reserve.. I think this entire subject becomes crystal clear.. you now have a tire spinning 30mph faster than your guardian angel can fly.. and it is going to happen so fast you wont have time to react..

Most of this subject is pretty much moot if you are not approaching the physical limitations of the machine.. A brand new guy riding the novice group? vs an experienced guy riding the "A" group..

now do you want to learn a bad habit early you gotta fix as you go faster? or learn to do it the right way while the cost of a mistake is just a slow lap..

I think it goes well with learning "smooth" throttle control as well.. you can be herky jerky all you want running 30 seconds slower than the track record... if you are within 5 of 10 seconds of that same record on a Busa? I would advise you be REALLY SMOOOOOTH... cause if you are not... I can just about promise you scratch up your bike :)
 
The chart I posted doesn't go by RPMs because the tach wire wasn't hooked up. It only relates to tire speed. The beginning of the curve starts at 2,000 and the end is the 11,600 hard limiter. The torque difference between 7,000 and 10,000 is almost 20 ft/lbs on my bike.

The high-side comes from the bike stepping so far out sideways that the rotation of the tire is almost perpendicular to the direction of travel. At that point the tire will get enough traction, in the direction of travel, that it will pitch you off the side of the bike in said direction. The rider error is too much throttle input for the available traction. When traction is lost because of the overwhelming torque the RPMs climb until they are stopped by the rider of the limiter. If there is 5,000 RPMs available to rotate the engine will deliver it, and the bike will turn sideways until the tire stops accelerating. If there is only 2,000 RPMs remaining the sideways movement will be stopped much earlier, and will almost certainly prevent the high-side. The engine acceleration happens so fast you will not have time to react before it hits the limiter. Traction control can help prevent it because it checks tire speed once every 1/60th of a second. Human reaction times are 1-1.7 seconds. A high-side only takes .5-1 second to occur.

I have had the tail of my Busa step out by the width of the bike before it hit the rev limiter about 2,500 RPMs later. If the engine had 5,000 more RPMs to give the bike would have likely increased the amount of deflection double that amount, resulting in a quick and painful flight. So far I have gotten very lucky on the street and track. I hopefully got the high-sides out of my system when I used to ride dirt. Most of the dirt high-sides were for the same reason as described above.

In summary:
More torque and available RPMs = More deflection.
Less torque and available RPMs = Less deflection.

Having a choice, I would prefer to learn from the mistakes of others. I thought I knew a lot about riding until I had my first track class. I discovered I knew very little compared to the instructors. When I listened and applied the teachings I made remarkable improvements my skills.

Tuffbusa once told me that almost every single high-side he has witnessed, the bike was one gear higher than it should have been for the given corner. The class instructors echoed the same message.

If you have never attended a performance riding school do it! I'm not talking about an open track day where you pay a fee to do laps. The only thing that will accomplish is reinforcement of any bad riding habits you may have. I'm talking about classroom time and one-on-one riding instruction. 2-Fast.org was the best $300 I have spent on myself to improve my skills. Knowing how much I have gotten out of that class I would have paid twice that or more. I will be taking the Mike Sullivan riding school next year. That should help smash a bad habit or two when I get back to riding.
 
OK. I see the point of using the rev limiter as a safety feature, and I can understand that in racing where things can get out of hand due to the throttle being opened too far too quickly, this becomes a valuable tool.

But, I always - I mean this is a reflex, I simply can't do it other way even if I wanted to - always open the throttle smoothly and slowly on the exit. As the rear is about to brake lose, I will feel it, wouldn't I? I did experience small slide and grab shakes in the past. And even if it breaks lose for a moment, it would hook up pretty quickly because: a) the torque exceeds the traction by a small margin; b) as the rear steps out, the bike's lean is reduced, so as a result the contact patch is increased. At the least, the rear will not go all the way out to 90 degrees, but will stay at some angle - and will hook up eventually without the rider doing much of anything.

I agree that there is no time for the rider to do much to save the situation. The entire approach is to get into this situation by overstepping the traction limits by a very small margin.

I am curious, when you watch dirt trackers on the oval full of dirt, they pretty much constantly spin the rear. Do they rely on the rev limiter or on their fine touch to give it enough throttle to force the rear to spin, but not so much that the rear spins out of control?

As to high performance school, I am far away from hitting my personal limit in riding, i.e. I have plenty to work on. At some point, perhaps I could do that. But to me it's silly to take a school when I didn't nail down the basics. I am also not a big fan of blindly following directions. My approach is to understand, comprehend, have a plan and work on it slowly. If it doesn't make sense to me, Rossi himself would not convince me to do it.
 
Quote
"Tuffbusa once told me that almost every single high-side he has witnessed, the bike was one gear higher than it should have been for the given corner. The class instructors echoed the same message."
Unquote

It's hard for me to comprehend the conclusion made from this statement. I would speculate that those riders made a mistake of gassing too much on the exit which caused the rear to start sliding all the way out, and then possibly chopping the throttle in fully automatic panic reaction which caused the rear to hook up while being at a big angle to the line of travel. And yes, in such circumstances staying in high rpm might've saved them or might've not. But, many times more riders who rode in taller gear went through those turns with no ill effects. So, the key factor here is to not make a mistake. And the secondary factor might be that if the rider made a mistake, being in shorter gear may or may not help to avoid a highside. I personally, at this time have no intention to consistently spin the rear on exits. So, in my mind, I re-inforce the correct reaction to such occurance - ignoring it. Like Code put it, it's a built-in safety feature each motorcycle comes with: the rear will step out just the right amount to keep everything in balance, maybe a light reduction of gas all the rider needs to do. But, try to achieve that without the right reflex - impossible.

I remember years ago, I was visualizing what I am going to do if the rider crashes in front of me. The very first thing I was working on was to look where I needed to go as opposed to looking at the rider who is sliding down the track. So, at one track day, I was still on my Katana 600 at the time. So, I stuck behind a rider about 10 -15 ft in front of me in no passing zone at the turn enrance. Another new rider thought he knew better, passed inside me in the no passing zone, and then attempted to pass the rider in front of me. Unfortunately, the rider in front of me turned in and the two riders collided right in front of me. What happened then was very interesting. I did not experience any scare, my heart didn't fall, I made no concious effort to do anything. The moment the two riders collided, my eyes simply looked where I needed to go. I saw the riders collide, but I didn't see them going down. I was looking through the pass of escape past them. The correct actions happened all by themselves, and only thanks to my visual practicing, like a computer executes a piece of code - there is no thinking or emotion involved - it just does it.

And ultimately, that's how the riding should feel (and I did experience that, not all the time though). Everything happens by itself, you spend almost no attention on anything, you are just sitting there relexed, taken for a ride, and some other force takes care of all bike controls and all inputs, and you are just enjoying the ride, maybe humming in your helmet your favorite tune. That's kind of perfect execution I am striving for, and that's what makes riding worthwhile to me.
 
One thing that has helped me on smooth throttle control is having my pinky and ring finger on the bar end. Produces just enough drag to keep it smooth. If I ride with my whole hand on the throttle, I get real choppy.
 
IG - Let's see if Tuffbusa will explain that statement. I'm feeling too loopy from my meds to keep my thoughts straight. Besides, he can explain it much better than I can right now. One thing I can say for sure is that we are talking about riding on the bleeding edge. It doesn't take much for things to go wrong if you are using up 90% of the total traction in the corner, then add a few more lbs of throttle than the tire can take.
 
Flat trackers are INSANE:laugh: HD 750 won't spin up like your Busa, curves & gearing more consistent on OVALS. Still a good place to see highsides IMHO :rofl:
 
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