racer

That is an excellent idea. You might consider spending some time around some of the experts in the pits. As a corner worker, chances are you will be a welcome guest/addition to any gathering. In addition to picking some brains, you will be in a unique position to observe on track details up close and personal. There is no better seat in the house from which to learn.

I'm not sure I follow your first corollary. You start off describing acceleration and then refer to constant speed. I'm missing a connection somewhere. If you accelerate a little too much (not enough to spin the rear tire) then too much weight will transfer to the rear and the front will become too light to take advantage of optimum traction. However, I'm not sure we can make a blanket statement about which wheel will slip first (rear overload, front underload) without knowing more about the situation. That said, generally speaking, most mid-corner falls are low-sides unless the rear spins up. If you don't accelerate (enough) or decelerate, then yes, the front will overload and slip first.

avih, I have finished reading your last post and I find your analysis right on the money in all respects. There is one point of clarification I would like to add for the sake of those readers who might not have a clear grasp of the difference between speed, (fixed) acceleration and the relationship to throttle position which they imply. Specifically, as you know, acceleration is a term defined as (ΔV/T) or the rate of change in velocity or speed over time. To avoid any terminology issues among any pedantic minded scientists here, I believe that in scientific circles, for the sake of mathematical convenience, acceleration can be termed or graphically represented as positive or negative; but, for our convenience, we regard all acceleration as positive and rely on the term "deceleration" to indicate the opposite. So, "fixed" or constant acceleration indicates a constant rate of increase in velocity or speed over time. That said, there is a terminal velocity for any discrete position of the throttle, hence, fixed or constant acceleration implies continuous change or increase in throttle position. That is, to maintain a constant rate of increase in speed (to maintain a constant 60/40 weight bias), we must continue to add throttle (smoothly and slowly). As to your conclusion re: constant radius, I will need to think some more about it. My gut says it may simply be a matter of "neglictible" significance at 60/40 accel. In other words, for our intents and purposes, the rate of accel is so small and the proportional difference in radus so small as to be imperceptible or nearly so. Or, it may be something else. In any case, what you said makes sense and I will have to think more on it. Time. r

Good lord. It took me a week to find a time slot to attempt to reply properly to your last post and I still ran out of time before I could finish editing for clarification, ie. I'm still not finished replying to your last post! It's probably going to take me a month to find the time just to READ this one! Time.

oops

No, it doesn't. Not if you apply the correct amount of acceleration to acheive 60/40 weight balance, the bike will hold a continuous line. Once you begin to exit and accelerate harder, exceeding 60/40, your line may widen. Not unless you steer it up by applying pressure to the handlebars. If we choose to, yes. Should and can? Are you talking about body position? As we accelerate, more and more weight DOES move rearward as the result of accelerating, no matter what we do with our bodies. OK, sure. But it is the leaning phase that is most important and critical to how much speed and acceleration we will be able to carry through the exit and on to the next phase. When and where and how we begin to accelerate at max lean is what will determine everything else. Hence, "it is all about" accel/decel at max lean. Everything begins and flows from that point. (Hence, why folks are posting photos and asking for advice about their body position at max lean.) I hope this helps you to start to get an idea of the big picture, avih. There is so much more written about this subject in the Twist of the Wrist books, especially Twist II, elaborating on all the ways how what happens at max lean dictates how fast the rest of your lap will be. If you have any questions after re-reading them again, I will be happy to help. Regards, racer

Hi avih, I've finally found enough time to respond in detail to your post of last week. Please take my reply in the spirit it is intended, which is to be helpful, not to be argumentative. I don't claim to know everything, but, for what it is worth, I've been riding for over thirty years, studying Keith Code's methods for over twenty years, and, I have several boxes full of podium trophies from more than ten years of racing. I only wish to share my experience for the benefit of others. That said, please forgive any untoward tone or verbage. It is not intentional. Neglectible? For your benefit in learning English, there's no such word in our language. However, I could assume you meant either the closest word, "negligible", meaning small, insignificant, irrelevant... or invent a direct meaning for "neglectible", such as, able to neglect or ignore... perhaps? Which is patently untrue. Yes, the degree or rate of acel/decel which one is able to apply at max lean is less than at more upright angles, but, it is precisely for this reason that it cannot be neglected, ignored or considered insignificant. In fact, throttle control at max lean is perhaps the single most important (and least able to neglect) action that any rider ever makes. Um... huh? The only force? What about gravity? Regardless, you are incorrect that "it" (cornering forces) need to be applied evenly in this phase. As I (and Keith, and many others) have said, again, these forces need to be applied biased f/r to match the relative sizes of the contact patches as that is what determines the load bearing capacity of each tire during this phase. And... ? Are you implying (again) that time spent at max lean is "neglectible"? How and when you begin to accelerate largely determines how much you can accelerate and/or how much exit drive you can achieve down the straight to the next corner. The line you choose largely determines when you can start to pick it up to accelerate harder. Again, you are contradicting what you said in your previous post when you agreed that (theoretically) you would want to move the body toward the rear when braking to avoid overloading the front tire, the game under braking while leaned over or straight up and down, is to not overload the front tire in the process. The forward force of braking can move 100% of the weight to the front tire no matter where your body is. Moving rearward might theoretically increase the limit of braking force applied to cause that 100% shift. I don't really know, but, it sounds good. That said, making sure that there is enough weight on the front to apply the brakes is important. Simply rolling off the gas is generally enough to transfer the necessary weight in most situations, ie. you don't need to climb up on the gas tank before you apply the brake. (This section needs to be re-written due to lost copy during editing. No time now.) While it is true, as we said before, that, like braking, having enough weight on the rear before accelerating might help prevent breaking the tire loose if you whack the throttle open hard. Throttle control is the primary factor and once we are in the process of accelerating, the optimum balance or relative bias between the front and rear is dictated by the relative size of the contact patches, front and rear at max lean. It is not so much a matter of more or less absolute weight on the rear tire when leaned over, it is a matter of how much weight compared to the front that will define the available overall traction/load capacity. That said, once you begin accelerating while leaned over, like braking, the trick is to not overload the rear tire, either with "weight" or cornering force, or with too much throttle. My point is that moving your body forward will (theoretically) allow more throttle to be applied to achieve 60/40 or optimum bias for max available traction, hence, max potential for acceleration. If there is 40% weight distribution to the rear and 60% to the front, the amount of acceleration one can add will be limited or less than what it could be if it was 60/40 because the weight distribution does not match the contact patch distribution. Mm, not quite. You are looking through the eyeglass in reverse, so to speak. The more you accelerate, the more weight there IS on the rear because you are accelerating. The more you move you body forward, the harder (theoretically) you can accelerate and maintain optimum wieght distribution hence, maximum traction and max potential for more acceleration. (continued)

lol You meant 10% of the gross, right?

How odd. I searched for it exactly one month ago with the intention of posting an Amazon link along with the link to the school store I posted above in this thread and it came up empty. I just did another independent search now and got the same page you did. Huh.

Thank-you for bringing this book to my attention, Red. I've never heard of it before. I wonder why it isn't available here on the website in addition to Amazon.com. Ironically, I can't find the Twist of the Wrist books on Amazon.com.

Hi guys, I've never quite understood Keith's explanation for calling it a "pivot" point, but, in the sense that it is a fixed point and your body moves, I suppose it is an accurate description. I tend to think of a pivot as a point or axis about which something else rotates or pivots. Anyway... The way I explain or describe the concept is that it is "pushing off of" or "pushing against" something solid with one part of your body to push against something else with another part of your body enabling you to use the strength of your entire body in the process. In this case, it's about using the strength of your entire body to push against the handlebar rather than using just your arm. It means the effort to push on the handlebar literally begins in the sole of your opposite boot anchored against the footpeg in the same way that a boxer's punch begins in his feet or a batter's swing starts in his cleats so they can utilize the strength of their entire bodies in the effort. When a martial artist hits or kicks, they put their entire body behind the effort. It's like the old expression, "putting your weight into it" or "behind it". Granted there is a rotational or "whip" element for the other sports examples I mentioned that isn't really included for us, but, the main idea is the same. So, in a nutshell, if you want to quickly counter-steer the bike to the left at speed, you literally push off the right footpeg, using the strength of your entire body, to apply pressure to the left handlebar. racer

ikonoklass, My post of a month ago was addressed to everyone in the thread.* It was not my intention to single you out nor to accuse or imply that you had not read the material in question. Nonetheless, my apologies for including your name in the address and for any insult you may have taken from it. Aside, since you know "what it is", perhaps you will be kind enough to enlighten the other members who don't. Cheers, racer * et al. is a commonly used abbreviation for the Latin phrase et alii meaning: "and others".

Thank you. Indeed, I'm sure it does. I wasn't really awake yet when I quickly skimmed through it over first coffee this morning on yet another night of five hours sleep. Unfortunately, I am unable to devote the time that it deserves tonight either.

avih, I've re-read your post with another cup of coffee and perhaps I judged it too quickly or harshly. Again I apologize. I'll give it another read when I come home from work tonight.

I guess I should write and edit my posts on a word processor before posting them. I forget that someone on the other side of the world might be lurking to respond before I have five minutes to finish editing... lol. In any case, I apologize. I missed all the "IMO"'s I guess. For what it is worth, I disagree wiith your entire post, as do Keith Code's teachings... IMO. I suggest you re-read the books. Cheers

Hi avih, Generally speaking, I/we come here primarily to learn and discuss Keith Code's "teachings". Here on his school's website/forum, that is. Based on your postings, it seems that you are unfamiliar with the Twist of the Wrist book series. You can purchase copies on the website "store" section here. Keith has trained more world champions than anyone. For what its worth, I used his teachings with great success to win many trophies at the national level for a decade before I retired from professional motorcycle roadracing. Good luck, racer

Sounds about right to me On entry you have weight forward due to breaking, so you keep your body backwards. On exit, while the weight shifts backwards due to acceleration, you move your body forward to keep it from wheeling and balance the weight shift. That's true. But, my point is that there's more to balancing the acceleration phase than merely keeping the front wheel down. The weight needs to be optimized front to rear to "match" the available traction. The relative load capacity of each wheel is directly proportional to the size of its contact patch. The rear contact patch has more available traction/load capacity than the front because it is larger. Hence, the rule of thumb (according to Keith) for "standard" acceleration when leaned over (near the limit of traction) is about 60% weight on the rear and 40% on the front to match the relative difference in size of the contact patches. This rough ratio will give the maximum potential traction. Right, but, my point is that there is more to the story after we begin to accelerate. After we begin to accelerate, the overall weight bias shifts rearward proportional to the rate of acceleration. So, the more body weight we can shift forward as we accelerate, the more potential for acceleration we gain while maintaining optimum conditions for maximum traction. If we are at say 45/55 (r/f) when we begin to accelerate, some weight shifts rearward. At some discrete rate of acceleration for a given distribution of body weight, we will achieve the optimum 60/40 (r/f) overall bias. If we shift our body position to distribute more body weight forward such that overall bias is altered (back to say 55/45), we must (or can) now increase our rate of acceleration to regain our optimum (or standard) 60/40 ratio for maximum traction. Does this make sense to you?

So, regarding your near highside but lowside and butt being up higher... My first thought was that more weight over the rear might prevent the rear from spinning up, and, once spinning, more weight would obviously be a bad thing. But... then I backed up a step and remembered that proper weight bias is about load vs traction and directly proportional to the difference in size of the contact patches, ie. 60/40. Hence, more weight forward should allow harder acceleration (and more weight shift) to achieve the proper 60/40 bias. Conversely, when entering the corner, more weight forward risks overloading the front tire. Hence, if hanging the torso off parallel shifts the weight bias forward as was discussed, high during entry and low under acceleration makes perfect sense... to me. Any thoughts?

Hi sleepr (and everyone else), I was unable to attend the races at Mid-Ohio last week due to last minute illnesses at work leaving three department heads out on top of the GM being on vacation. When it rains it pours? Murphy's Law? "Shorthanded" doesn't quite say it. My time off was scheduled weeks in advance, but, there was simply no way I could turn my back. So... I took the opportunity to download the races from Mid-Ohio this afternoon along with the AMA races from Laguna Seca two weeks ago. And, well, I decided to watch, with a technical eye, the front runners, er... front runner, Mat Mladin, as he ran away from the field... specifically for body position as it relates to our discussions here and Keith Code's teachings. In some camera shots I could clearly see Matt in perfect CSS style, head kissing the mirror and body parallel, yet, in other camera shots, he was clearly sitting nearly upright and, well... crossed up. After awhile, I began to notice that the shots where Matt was sitting up were on corner entry prior to the apex and the parallel form was consistently seen exiting the corner! Can anyone say epiphany? It was then that I recalled a thread from this past spring in which Cobie joined in and tried to get me (us) to think about how body position affects weight bias, in general, and, more specifically, during the "hook turn". And in that thread, a CSS student who had recently attended a school remarked in some more detail, expanding the BP description to include the entire corner. Something to the effect of staying high at the corner entry and then dropping down for the exit. That discussion came flooding back as I realized what Matt was doing. (Oh man, I can't wait to get back on track.) That said, my next thought was of you and your photos in this thread, sleepr. And I now have to ask (!) ... can you recall what parts of the corner you are in for each of the photos you posted? Eager for reply, racer PS - I have to add that I was thoroughly BORED TO DEATH by the AMA races at both Laguna and Mid-Ohio. Very disappointing to say the least. Perhaps it is time for the AMA to go spec on tires. Not that I think that would solve the problem entirely. Unobtainable FACTORY bikes and two sets of rules have a been a fact of life here in the states since I started racing twenty years ago. But, well... let me put it this way... I'm REALLY glad I didn't plunk down the $400 USD it would have cost me to travel to, and lodge at, Mid-Ohio last week. REAL Glad. How sad. (Thank God I also downloaded the WSBK from Great Britain and the BSB from Knock Hill... which are queued up as I write this. BYE!)

I know exactly what you mean. I've lost 25 lbs since April and still have another 30 to go myself. I know how much better you must feel. And how much more difficult it is to ride like that. Congratulations on your success! Now the real work begins, eh? The first twenty lbs were easy. The closer we get to ideal weight the more work it takes to lose it. I may have to give up beer altogether. And thanks for taking that observation in the spirit it was offered. It can be a sensitive subject and I was concerned that you might think I was, er... attacking you. I never do that. Seriously though, I don't know if having your butt up higher would have helped or not, but, you did well to save it as much as you did. Did someone tell you that hanging your butt off too much decreases rear traction in that scenario? My initial reaction is to think that having your butt higher would put more weight over the rear. But, I guess the bias might go forward if your torso is off. In any case, it would make you lean over more to maintain the same line. And, accelerating while leaned over, I think more rearward weight bias would overload the rear tire faster. What do you think? That is a great photo and a better story to go with it. I love things like that. Total impact at speed complete with shattered plastic and tire marks; but, everybody was in too much of a hurry to spare the time to fall down, ha ha! Excellent! It almost makes you want to leave the damage since it's such a great conversation starter, eh? Too bad your ram air intake is there.

EXCELLENT! I think the first book has the most info about choosing RP's and basic "line theory". Indeed! No doubt. It can be very challenging. But learning to deal with that is also part of the game. If the track is really full, it can be difficult to find some personal space. When I feel the need for some open track, I'll sit at pit out and watch for a couple of laps to get a feel for where the "clumps" are. Then I'll wait until the biggest group goes by and/or the group with the biggest empty space behind them and try to insert myself behind that group or in that space. That way, assuming they are faster than I am, it will give me the most time on my own before the next group catches up. Then I'll ease off a bit and let the next group by to catch the next empty space. There's only one way to find out! But I think you might be surprised. I'll bet your lap times would be more consistent than you think. It is a skill that can be developed. And being coached is an invaluable experience. But, keep in mind that, even when they are there, Keith and crew can't really work on it. Only you can. The real goal is to learn how to learn, how to be your own coach, so to speak, when Keith isn't there. You can start by working the same drills even when you aren't at school. And perhaps find a buddy to work together so you can critique each other. Does that make sense? racer

Hi sleepr, I don't know which photo is the most recent, but, I think the first photo posted looks the best. Your head is lower and further over than in the other shots. And your body is almost parallel. There's room for improvement, but, it doesn't look bad. I think the second and third photos show you sitting up more and a little crossed up. FWIW, forgive me for saying so, and I'm sorry if I am wrong, but, it looks like you might be a bit on the heavy side. It isn't everything, but, physical conditioning and good health do contribute to the package. In any case, I know my beer gut sure gets in my way! Thanks for sharing your pic's. Keep up the good work. racer

But you will anyway?

Great. As far as I can see, the last on-topic post was mine. Whenever you are ready.

Thank you for your opinion, avih. Are you serious? Not that I am actually interested in your opinion of my opinion of Meat's opinion of me. In any case, I think Meat is capable of defending himself, eh? That said, since you brought it up, with all due respect, if you want this thread to get back on topic, you might consider not continuing the discussion in another direction... as you just did. Regards, racer