racer

Roadracing World magazine publishes a large schedule for any and all schools/groups. Or you can Google the tracks near you for their schedules. That is what I do when looking for events to canvas for new clients. And, of course, California Superbike School posts their own schedule on this website. If you haven't attended a school yet, this is where I would start before spending money on track days. http://www.superbikeschool.com/schedule/ http://www.roadracingworld.com/calendar/glance/ http://www.infineonraceway.com/schedule/raceway_schedule/ http://www.buttonwillowraceway.com/

Welcome to the forum, rydnonedge! Glad to have you ridin' on board! Have you attended a superbike school session yet?

Well, sure. Like you said... decreasing radius with late apex, double apex or perhaps a combination of turns that aren't really what they seem, ie. setting up for the final apex and exit defines how you get into the combo... if you know what I mean.

Hi Duke. Can I call you Duke? The baseline I was given many years ago by an international superbike racer (with several national championships to his credit) was that the best spring for a baseline is one that takes zero or as little pre-load as necessary to achieve the desired static sag (0.75-1.0 in or whatever). In fact, he said that he set his bikes up with "negative" pre-load so the bike could come up off the spring under heavy braking and allow the rear wheel to stay in contact with the pavement better. I guess if the spring was short enough and you dialed the pre-load ring all the way out so there was a gap between the spring and adjuster ring when you lifted the rear of the bike, that would do it. Anyway, I also hear about WSB or MotoGP riders changing shock springs from track to track, so I guess there can be some subjective feel about how one likes to tune a suspension, ie. if you prefer .75" or more sag, or perhaps a softer spring for certain conditions, then different springs would be needed under different conditions or circumstances. My personal feeling is that typically, the less you have to pre-load a spring the better as that should theoretically give you the most potential range of motion and keep you furthest away from the binding point of the spring, ie. operating in the area that the spring was intended to operate in. That said, this doesn't take into account the subtleties of different rates that might be important depending what type of track you are riding and what the conditions are. Personally, I set it and forget it. I have enough to worry about tuning the carb(s) on a two stroke. I make suspension adjustments for rain or a bumpy track, or between a slower tight twisty track vs a fast sweeping track maybe, but, I don't change springs. At the end of the day, unless you are Rossi or racing AMA nationals, you probably don't need to worry too much about it. Though, I do find it interesting that you got such a wide range of answers from people. However, remember that Traxxion Dynamics are the Penske people here, so, my gut instinct would probably be to lean toward what they tell you about their shock. If you were running Ohlins, I would listen to Ohlins. Finally, the bottom line is that I don't think there is any single answer for everybody. If you want to know what is good for you, buy several springs and spend days testing each of them. However, if you aren't already running competitive lap times with what Max tells you, it probably isn't worth your time and money. I'd say concentrate on your riding. A good rider can ride around most anything well. And then you will have the necessary feel to know what you prefer. I know that probably isn't the answer you wanted to hear, but, like so many things, any choice you make is a compromise or a trade off somwhere. I'd start with what Traxxion Dynamics tells you. But consider what other experts have to say too. Hope that helps. racer

Thanks for the link. Tony's name is certainly well respected when it comes to information on motorcycle chassis. Unfortunately I have not had much time to devote to anything outside work and sleep lately. Perhaps I can do some reading over the holiday weekend.

Wow. That's one of those lifetime Moments that's just beyond words cool. ( No big deal... um... yeeaah. Right.)

WHAT!?!? Of course it's a big deal!! Congratulations, dude!!! The day I broke 2:00 on a CSS (1987) 600 Ninja at Mid-Ohio is indelibly stamped on the inside of my forehead forever. I'll never forget Keith reading out each students fast lap to the classroom after the last session of my first day ever riding a 600 on track. I waited on the edge of my seat hoping and praying to hear that I'd achieved the goal I'd been shooting for all day. And the pride, joy and sense of accomplishment I felt when Keith announced my time of 2:00.07 stands alone in my memory. Yes, I can look back and giggle now that I've lapped fifteen seconds faster today... on my 125. But even standing on a national podium wasn't much better than that moment. Congrats on your "bump" dude! Keep up the good work! And don't be a stranger... now that you're almost famous. r

Wow. OK. Cool. This will be a welcome challenge... lol. This isn't a subject I know much about or that I've given much thought to, although I have read that even the major factories chase their tails over it. I will tell you what I know and try to do some research on it to form some discussion. From what I understand of it though, it is something of a black art. In a nutshell, although a perfectly stiff frame/chassis would seem to be desirable, ultimately, unlike a race car, there is such a thing as "too stiff" for the motorcycle chassis. As I understand it, part of this fact is due to the shortcomings of the telescopic front fork suspension. And moreover the inability of a motorcycle suspension in general to operate efficiently while leaned over, ie. it can't react to bumps in the road when it is sideways. Obviously, the details of where and why the chassis needs to flex, ie. near the headstock and swingarm pivot, as opposed to the engine cradle or spars which need to be stiffer, or how to brace the swingarm for torsional rigidity while allowing some lateral or horizontal flex is a huge subject far beyond my own experience or knowledge at the moment. However... If I recall correctly, chassis flex first became a big issue in the seventies when big motors (like the Kawasaki Z1, 900/1000/1100 or the H1/H2 two-stroke triples) became so powerful that they literally twisted the old tubular frame bikes up in knots. Chain pull would cause the swing arm to actually twist in its pivot and the frame with it. Sometimes the chassis would actually bend and stay bent, but, more often, it would wind itself up like a spring and release that energy in an uncontrolled fashion. (Just ask the guys who raced them... like Eddie Lawson, Wes Cooley or... ahem.. Keith Code). So, stiffer frame/chassis became the goal. However, frame technology, materials and design have come so far that today's chassis/frames can be so light/stiff that they actually start to vibrate or oscillate allegedly causing front end "chatter" or perhaps masking feedback of what is happening at the pavement. Or whatever else riders complain about before they begin removing engine mounting bolts from their frames... like Colin Edwards allegedly did his last year of WSB. Using Google, I found some interesting articles like this blog: http://firstsynn.blogspot.com/2007/04/moto...ame-primer.html Here is an interesting "engineering oriented resource": http://www.dim.unipd.it/lot/HTML%20flexmot...%20Madrid1.html

If you can keep the throttle pinned while bending it in, then do so. If you can't keep it WFO, try to back off just a little bit without using brakes, bend it in and then get back into the throttle... smoothly. Be as smooth as possible with the throttle throughout the rolling out and in process. And start early so you can ease off smoothly without being rushed into making a sudden throttle change. The primary goal is to upset the suspension as little as possible to help maintain as much speed as possible. The LAST thing you want to do is close the throttle. Good luck, racer PS - Sometimes this type of corner combo lends itself to a short shift. If you find the sweeper is so long that you need to upshift somewhere in the middle (especially in the first half of the corner), you might try short shifting (up early) before you turn in. Try to carry the higher gear through to see if that might be smoother and faster than trying to up shift at high speed while dragging your knee.

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One of the best and most meticulous mechanics/machinists/builders I know is Joe DiStefano here in Pittsburgh. He built and tuned racing Ducati's for Fast By Ferracci before starting his own shop about fifteen years ago. He spends much of his time traveling the country doing dealer support for Triumph(?) (I believe) these days, and there is a waiting list for his time, but, when it comes to building Ducati's (or any motor), he is tops. He takes great pride in his work, honors his word and stands by his work. However long it takes to do the job right at the price he quotes is how long it takes.... at the price he quotes. He is a real stand up guy and one of the best people I know. He did my forks and motors (that won many trophies) and is a master at utilizing his dyno to squeak every last BHP out of a project.

ROFL So sad but so true! I have so little desire to ride or race a 600 after racing my 125's for so long and have yet to fulfill my dream of racing a 250. And now it seems two strokes are going away for good again. HRC and Yamaha stopped making new models several years ago and only build a few machines to order every year and this is the last year to get on a waiting list for a new one as the FIM is giving them up after 2010. It makes me want to cry.

Hi Daniel, Welcome to the forum! I'm sorry to hear about your fall and I hope you heal quickly. That said, my first question is the same as nicenezy's: How long have you been riding? Unfortunately yours is a story I hear everyday with increasing frequency recently and one, I am afraid, that may become all too familiar in the coming months and years as the price of petrol in the USA climbs ever higher. Folks with little or no riding experience buy a motorcycle, perhaps for basic transportation in an effort to relieve a fuel bill that out-paces their mortgage or rent, and promptly go out and injure themselves (or others) within a matter of days or weeks from the date of purchase. What really makes me feel sad for some these folks is that some of them might never have even considered riding a motorcycle otherwise. Some simply don't understand the risks or, in addition to a lack of basic skills, lack an appropriate level of respect for the danger. The skill required for riding a motorcycle safely is not akin to riding a bicycle or driving a car. And something that weighs a quarter of a ton moving at a mile a minute is a loaded and potentially lethal weapon for anyone around. It is a privilege and a responsibility. I suppose it can be something of a Catch-22 or a double-edged sword, being a beginner and needing to gain experience, especially if one is a very large man, say well over 6' tall and 220 lbs +, and is simply too big for an appropriate sized learning machine like a Ninja 250 or a Honda Rebel. In my humble opinion, and the opinion of many others qualified, including the governments of countries like the UK, any bike bigger than that is simply too much motorcycle to learn how to ride on. I don't recall the precise figures for the UK, but, I know you can't go out and be licensed to ride a 600cc machine without years of experience and testing on a small machine to prove you are ready for something bigger. A licensing system similar to the licensing structure for piloting aircraft. Which is clearly appropriate considering the level of risk (to the pilot and the public), and the level of skill required to simply operate an aircraft safely. In my opinion, the level of skill and risk for riding a motorcycle is comparable in both complexity and scale. And the UK has it right. My opinion is that an MSF safety school and Keith Code's books should be required reading for all new riders eveywhere. So, whatever your personal situation, if you aren't ready to participate in a Level I CSS class on track, you are certainly ready to attend a new riders school like the one offered by the MSF (Motorcycle Safety Foundation) and absolutely ready to read and study Keith Code's books starting with A Twist of the Wrist I. Since you are new, I will tell you that I post that opinion at least once a week here. Not because Ketih is my friend or I am jazzed by the racing motorcycles, but, because reading his books, at the very least, have saved my life more times than I can count. I also urge every rider who crosses my path at the motorcycle dealership where I work to do the same. My advice is to order the first book, A Twist of the Wrist here and study for your life while you heal. That alone will start to build your confidence. Just knowing that there is some place to start, a certified first step in the right direction. And please feel welcome to bring any questions you have about riding here. There are many members who are familiar with Keith's books and have attended CSS many times. And when they aren't traveling around the country teaching, really good coaches like Cobie and 2bigalow who are happy to answer your questions with sincere and helpful information. They are trained to make you feel good about learning, not bad for asking "beginner" questions. So, I hope I haven't scared you, but, rather helped to instill a healthy respect for the wonderful journery you have chosen to embark on. Riding motorcyles has added an immeasurable quality to my life that is priceless. Not just for the joy of riding but the many experiences and friendships I have made along the way. And all the doors that were opened because of them. It's rough to take a fall so early, but, you are not alone. Whatever you do, make the effort to take responsibility for doing it right and don't give up. Best regards, Bill PS - That fracture should take several weeks to heal which gives you plenty of time to get cracking on your study program. So no excuses. Give up drinking Starbucks (or whatever) for one week and you will have enough money to fill your library with life saving information.

Great write-up, tweek. You really seem to have a good handle on what happened and why. It's just amazing (or not!) how it all starts and ends with attitude and intention. Get that part right and we have such a better chance of getting the rest of it right. Or at least much less chance of getting it wrong! And you are so right about those big changes. It can be so hard sometimes to remember to keep them small and gradual and approach my limits one step at a time when I am excited, too. And get some bloody reference points already, you wanker!!! Seriously, thanks for the write-up, dude. I hope other readers will get as much from it as you have. Cheers, racer

Returning to the question of the mechanics of why a motorcycle runs a wider arc or radius at higher speed... or back to square one. If the rear is responsible for direction under standard throttle and acceleration (60/40), then it follows that the mechanics of how the bike runs a wider radius at higher velocity must be happening or at least beginning at the rear. And it follows that the front wheel must turn out more to follow. So, merely increased centrifugal force at the rear making the main mass behind the steering head "want to run wider" and the increased centripetal force applied behind the steering angle at the front contact patch turning the front wheel wider?

Here's another nugget I missed from page 60 of Twist II: This discussion has definitely given me a better understanding of this chapter and the significance of the load on the front wheel. Due to the length of the wheelbase and the C/G, after a certain lean angle, the amount of cornering force will not allow you to lift the front, ie. the front will wash out (go wider) with too much or too little weight. So, the front is holding the line, but, it is still only following the line dictated by the rear of the bike. Ultimately, it is responsible for handling its part of the cornering force or load. Not the direction the bike is traveling. So, in that respect, I think I now see what Leftlaner meant when he said the front wheel is "commanded" by the rear. The bike is traveling where the front is pointed. But, the salient point is that even though the front wheel is holding the front end to the pavement and the bike is going where it is pointed, the angle it is turned is an effect of the direction the bike is traveling. Not a cause. The direction the bike is going is dictated by the rear. The front is merely handling its share of the cornering load. Does this make sense to you guys?

You know, Carl, you said something that has stuck in my mind. And it has led me to think about what is happening at the front while a bike is accelerating. To paraphrase, I believe you said something about needing a certain degree of acceleration just to maintain a balanced state between all the forces (lean, radius, velocity). And, to extrapolate, further acceleration (or deceleration) might be forcing the front wheel to be attempting to countersteer the bike even though the rear gyro doesn't let the bike come up, but that would seemt to be turning the front wheel inward. Perhaps that force (centripetal behind the steering angle due to trailing geometry) is turning the wheel outward and creating a steering force at conditions (of accel/decel) near a stable velocity? I believe a higher rate of acceleration has more effect on the rake: lifting the front, extending the forks and wheelbase. Though that seems different than a stable velocity that is merely higher. But maybe it isn't. Does it take an increased rate of (limited) acceleration to maintain a balanced (60/40) state when traveling at a higher velocity?

Have you read Keith Code's Twist of the Wrist books? I got both my copies of Twist I and Twist II from my public library, but, you can order the books, DVD's or videos from this website here. If nothing else, it will give you a good idea of what Keith thinks and why (assuming he hasn't changed his mind ). At best, the $20 might save your life. The books and schools have saved my life many times over. In general, the Twist books have been my riding bible(s) for fifteen and twenty-five years respectively. I can't recommend them highly enough and do, in fact, recommend them to every rider I encounter over my parts counter at the dealership everyday. Just like affording a good helmet, I ask them, "how much is your life worth?" I wish you good hunting in your search, sir! racer

The front wheel plays a significant role in keeping the bike up on two wheels according to its load. I don't think it plays a significant part in the direction the bike takes while leaned over in a stable state with standard throttle. Right. Higher speeds on a road bike is what I am talking about. But, I would humbly suggest that you try that experiment rather than rely on your occasional "memory". I think you may find that the arc remains the same. Well, now you are talking about sliding the rear. And, actually, I think the front wheel will continue to track while effectively turning into the slide. Hence, the bike may continue at the same angle (unless it leans further), and/or go straight... it will not tighten up. However, once the slide stops, the rear will then be pointing in a new direction... which will effectively be tighter. So, to answer Leftlaner's question: yes, there is a way to tighten the radius with the rear... by sliding it... and then catching it. It DOES revert to the single radius dependent only on lean angle with the front off the ground. It couldn't tighten up because the front was doing it's part to run a bit tighter radius than conical steering of the rear alone would do when both wheels were on the ground. The higher the speed, the more likely only conical steering of both tires finally comes into play. The lower the speed the more likely you would see a change in path because the front was steering more sharply. Forgive me for not being more specific. I was thinking along the lines of the ongoing discussion... wider arc due to faster speed. I should have said, "why doesn't the arc change... tighter or wider?" And, to reiterate, I do not think it will do either. I do not think I interpreted Keith's words. I quoted them directly from his book. I think they are quite clear and speak for themselves. Hence, I am taking them at face value. However, I believe it would be interpreting them to "guess" what he "really meant". Those declarative statements seem fairly air-tight to me. Not much wiggle room from where I'm sitting. In any case, I wouldn't deign to "guess" what The Guru "really meant". And as far as whether or not Keith may have changed his mind since he wrote those words, I believe he can speak for himself and guess that he would do so. This may be correct though the amount it alters it may not be radical enough as I just wrote. However perhaps this needs to be explored more (though I still, so far, say the front has more effect than you are giving it credit for). HOW do you think this works? I am still not entirely clear about the mechanics of why a motorcycle runs a wider arc at a higher speed.

clearvoiant ... ? he he he i suppose we all climb the bridge toward transcendence at our own pace ...

I think that's a great idea, Cobie.

Really sorry to hear about that, tweek. Follow your doctor's orders and take all the time you need to heal completely. No call for complications to keep you down for two more months, eh? Looking forward to it. It should be an invaluable tool for preventing similar 'incidents' in the future... for yourself and others. Keith warned you there would be an elbow shattering ka-boom?

Hi Chris, I was wondering about the significance of your forum handle. Does it refer to the motorcycle fairing designer, the ammunition, or the Latin proverb: si vis pacem, para bellum meaning If you want peace, prepare for war! Thanks, Bill

I must admit that the more I think about it, the more I'm convinced that you are right. Once the bike is stabilized at a constant lean angle and corner radius (no rider steering input), the rear wheel will "command" the front wheel. Which means that the radius will increase when more throttle is applied. Forgive me if I am misunderstanding you, but, that still sounds like you think the radius increases because the front wheel turns more outward. I am saying that the radius increases because the rear wheel steers or turns the bike more outward and the front wheel is forced to turn to "follow" or trail the rest of the bike. And I believe that conclusion is what Keith's words above must lead to. However, you and Carl may have a point here. Let's look at it. Carl said he believes that the radius will always be the same for a single wheel at a given lean angle no matter the velocity. Period. Hence, if the front wheel is off the ground (wheelie) while coming out of a corner, no matter how fast you are traveling, the radius will always be determined by the lean angle. (And it is only the front wheel turning outward that alters the rear wheel radius to follow the front with both wheels on the ground.) I disagree. I believe that the nature of the rubber/pavement contact patch at the rear allows increased cornering force to alter the path or radius of that single rear wheel. Here is some logic to support that assertion. If a bike is cornering with standard throttle (accelerating 60/40) at a given lean angle, radius and velocity with both wheels on the ground, why doesn't the radius 'tighten up' if you lift the front wheel? Why doesn't the rear revert to the "single wheel" radius dependent only on lean angle without the front wheel to steer it wider? See what I mean?