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  1. 6 points
    The cost of the 2 day class is pretty close to the cost of new Ohlins for my RnineT. I actually had to make that choice, and since I come from the old school 'ya run what ya brung' way of thinking, I figured that knowledge beats out hardware most days. Boy was I right. What was really marginal, harsh, and unresponsive suspension is now completely smooth, responsive, and supple suspension. As it turns out, putting yourself in the right place AT ALL TIMES and having your awareness focused on what is happening in the relationship between your yourself, your motorcycle, and the road surface....well, that changes everything. Of course, a new set of Q3+ doesn't hurt either. I can't count the number of off-road events I participated in where the cool guys with the best gear got their asses handed to them by some fat kid on a clapped out 20 year old dirt bike. Riding skill is riding skill, and they don't sell it on Revzilla. They do actually sell it at CSS however, and besides being fun as hell, it is hands down the best suspension improvement I have ever made. This is not exactly news to anyone on this forum, but I just had to crow a little. Rob-
  2. 5 points
    Like most any physically demanding sport, physical fitness (nutrition, hydration, strength, flexibility, etc.) is a factor in your ability to perform, and so are training, understanding, and practice. But, in my opinion, personalized coaching, and willingness to BE coached, are extremely important. I'll give you my perspective: I started riding quite late, in my mid thirties. I was very slow and very nervous and I don't think anyone expected me to have the potential to ride fast, let alone race (least of all me!), but I got really interested in the sport, got lots of coaching, and devoted a lot of time to really understanding the material, and my understanding of the material ABSOLUTELY changed and evolved as I rode faster. Going back and reading Twist II, I found lots of information struck me differently as my pace increased and I found techniques that were a bit vague to me at first became much more important, much more useful to me, because I NEEDED them more. For example, I could get away with slow body transitions at slower speeds but as my laptimes came down, speed of moving across the bike in a chicane became a limiting factor, I couldn't get through a particular section any quicker without moving over faster. Suddenly hip flick, which didn't seem very useful to me before, became a critical skill. That is just one example, but I have had, over the years, a BUNCH of breakthroughs like that, and have found that as I progress in my riding, becoming proficient in certain techniques and riding faster overall, new barriers crop up and as I address each one I get quicker again - and then encounter something else. How do I overcome the barriers? Through coming to school and getting coaching, mostly. Sometimes study of the material helps, sometimes analyzing data (laptimes, braking zones, lines, etc. from my lap timer or data logger) help, but coaching is what always makes the biggest difference - very often what I THOUGHT was my barrier turned out to be something different entirely, and it required the eye of a coach to discover that. Of course, my mindset while being coached is a huge factor in my ability to improve. If, for example, I came to school fiercely determined that I already knew "what my problem was", then I did not get nearly as much benefit from coaching because I was resistant to allowing the coach to help me. After I figured that out, I got even more improvements on my school days. I said physical fitness is important, but I am a lot older than many of the riders I race against, and not as fit as most of them, either, but my CSS training allows me to ride with fewer SR's and a lot less wasted effort so I can go faster and be calmer overall. I thought I had reached my riding peak years ago but I am actively racing this year and I am riding faster than ever before. I still get coaching as often as I can, generally I come to school as a student at least 4 days a year, if not more, and that makes a huge difference for me. It is not because I am in better shape, because I am not. It is because I understand and apply the riding tech better than I could before. I used to think, at the end of any school day as a student, that I was riding as fast as I ever would, because I figured I would just get older and slower.... but I'm not getting slower, I'm getting faster. Every time I come to school I get some new piece of information or tackle a new skill that adds something to my riding, and I get quicker. And what a thrill that is! And it is even better when some twenty year old comes over to your pit to ask you how you do it.
  3. 4 points
    Keith asked me to add a little more info about grip: The point on max grip is another many faceted process. Due to the slip angle tires never do have 100% mechanical grip, they actually are sliding. That is a prophylactic process as it cleans the spent rubber off the tire's surface but is ALWAYS happening, in every corner. It's sometimes overlooked in the traction arguments. In the end it's more to less, less to more SLIDE rather than more to less, less to more traction. Maybe that's just another way of looking at the same issue.
  4. 4 points
    This is a common enough question that lately Keith has put a new focus on the no-brakes drill with Level 4 students, having them re-do the drill to help increase their awareness of how much speed gets "scrubbed off" in a turn, and to make sure that concept is understood. There are, in fact, multiple Level 4 drills designed to increase the rider's awareness of this, and help the rider determine where, EXACTLY, one should have their entry speed set for a given corner. Dylan actually does cover this topic pretty thoroughly in the very first lecture in Level 1, Throttle Control, pointing out that the bike continues to slow down after the turn point, so trying to set your target corner speed AT the turn point can result in ending up too slow at the slowest part of the corner. However, I think for many riders who are new to track riding this speed-scrub aspect of throttle control may get lost; there is a lot to take in on that first day. And, of course, judging entry speed and speed scrub are the sort of thing that even the most advanced riders continue to work on, it does require focused observation and experimentation, and every turn is different so there is no "pat" answer that will work for every bike and every corner. Learning to observe the speed scrubbed after the turn point, and bringing up the entry speed gradually, is a good way to approach the problem - or make it a focus of your next Level 4 school day.
  5. 4 points
    It would be a rare 180 degree turn where you could roll on the gas as soon as you have your lean angle set (at the beginning of the turn) and be able to roll on continuously for the whole rest of the turn. If the turn was large, and U shaped (as an example) you would most often have to roll off (or at least go flat) on the gas in the middle of the turn, more or less treating it as TWO turns, the first part with one turn point and apex and the second part with its own turn point and apex. Depending on the shape of the turn, you may or may not need to make another steering input to change your lean angle at the second turn point (ie if the turn tightens up in the second part, you will likely have to make a steering input to change the lean angle for the second part of the turn). Alternatively, you could consider that your "real" turn point is somewhere in the middle of the 180 degree turn, a turn point that will line you up for the apex and exit you want. Everything before that would really just be pre-positioning to get to that turn point and you might very well be slowing down (off the gas and trail braking) ALL the way to the turn point which could be located near the middle of the 180 degree turn, or even later if it tightens up a lot at the end. You could try working backwards from the exit (if exit speed is the priority) to find the exit line you want, then find the apex and turn point (in the second half of the turn) that will line you up for that without any additional change in lean angle . That will be your "second turn point" (or real turn point if you are thinking of it as one turn) then work backwards from THERE to find an entry line from the first part of the turn that will get you top that second turn point. Does that make sense? If the turn is at the end of a fast straight and whatever comes after the 180 degree turn is slower, you may want to prioritize carrying the straightaway speed as long as possible and in that case you might choose a line that allows maximum trail braking as long and late as possible before you reach the second turn point, potentially sacrificing some speed in the latter part of the turn with a less optimum exit but a wide fast entry.
  6. 4 points
    I think visual skills are far more important than the others listed. I think your school thinks so too You teach that and throttle control first because it's the foundation of all the other skills in that those two things keep you mentally ahead of the action unfolding in front of you. The only other thing I would add as a skill is being smooth and steady on the controls. If your vision and throttle control are good, I think you'll find that those quick reflexes, bravery, and other skills will get tested less often!!
  7. 4 points
    Riding on the road is all about recognising and anticipating hazards, and managing those hazards. You can measure improvement by your ability to navigate those hazards faster, with less panic, or a combination of both. The vast majority of riding skills are applicable to both road and track. On the road you are just using them for hazard management. On the track primarily you measure improvement by your lap times. Not just fastest lap, but consistency in your lap times. Also good lap times while getting through traffic - being able to get past slower riders without being held up is not just an improvement in your riding, it allows you more track time to focus on improving more since your aren’t stuck at someone else’s pace for an extended period of time.
  8. 3 points
    Body Position The most obvious thing about any rider is their form on the bike. How do they sit and move on it? What’s their posture? Do they look comfortable or awkward, stiff or loose, Moto GP, or nervous-novice? Good body positioning isn’t just about being stylish——you can play dress-up in your older brother's or sister's cool boots but walking will be clumsy——it has a desirable result and we can define 'good body positioning'. Harmony with the bike, freedom of movement on it, precision control over it―with the minimum necessary effort. Survival Reactions Play a Role The bike itself can force poor riding posture. A shift lever positioned a ¼ inch too high or too low manipulates the rider into awkward and uncomfortable poses, limiting his control over it. Even with perfect control positioning, good form on the bike has its difficulties. Achieving it may look and even feel like it’s reserved for the young and flexible. This may be true to a degree but many of its problems are actually brought on by our own Survival Reactions, our SRs. For example, a rider who instinctively levels the horizon by tilting his head in corners, creates unnecessary tension in his body. Basics Apply Good form is difficult for riders who struggle with basics: uncertainty with basics has a physical manifestation. Just as joy or anger are obvious in someone, these uncertainties manifest themselves in awkward and unsuitable body positions. For example: poor throttle control prompts riders to rely on slash and burn hard drives out of the turns. Their 'ready-for-action', rigid body language telegraphs their intention. That tense anticipation of the drive off the turns loses them the handling benefits of being relaxed mid-corner. The Stages of Body Positioning There are three stages to body positioning: Poor form + poor riding = ripple-effect, snowballing errors. Good riding + poor form = good but limited range of control. Good form + good technical riding skills = riding that is both fluid and efficient. Number 3 is the goal of any rider training. The Ingredients Body Positioning has five distinct ingredients. The bike and how it is configured——its controls, seat, pegs and bar positioning. The rider's understanding of body positioning——how to properly position himself on the bike and why. Our Survival Reactions——how they create unwanted and often unconscious tension and positioning problems. Lack of riding basics——has or hasn't mastered the core technical skills needed to ride well. The rider's own physical limitations——height, weight, flexibility, conditioning. With those five points under control, specific techniques can be employed to achieve positive benefits in bike control. Form, Function and Technique GP body position does not address or improve 90% of the most basic and vital components of riding: Our sense of traction, speed, lean angle, braking, and line, to name a few, are not directly dependent upon or necessarily improved by stylish form. Clearly, body positioning isn't the universal panacea some think it is, but it has its place. For example, holding the body upright, counter to the bike’s lean while cornering has several negative effects. Among these, is the fact that it positions the rider so he can’t fully relax. This can be quickly corrected and solves the functional problem of tension from cramped and restrictive joint alignment: a key element in allowing any rider to relax. A bike related example would be too high or too low brake or clutch lever. It puts the rider's wrist into misalignment and restricts fluid movement. The Rules of Technique Here are my guidelines for technique. Any riding technique is only as good as: The validity of the principles it rests on. Example: The benefits of hanging off follow physics and engineering principles. The access it provides to the technology with which the bike is designed and constructed. Are the potentials of chassis, suspension and power able to be utilized as intended? Does the technique embrace them? The consistency with which it can be applied. Does it work in all similar situations? The degree of control it provides for the rider. Can the rider either solve problems or make improvements, or both, by using it? The ease with which it can be understood and coached. Does it take extraordinary experience or skill to apply it, or, can it be broken down into bite sized pieces for any rider to master? Which brings us to my first law of body positioning. Stability Comes in Pairs. Bike and rider stability are always paired―rider instability transfers directly to the bike. Body Positioning has but one overriding guideline: Rider stability. How a rider connects to the bike can bring about harmony and control and fluid movement or turn into an uncoordinated wrestling match. Ideal Stability Having stability AND fluidity of movement sounds conflicting; when something is stable it’s expected to stay put, unmoving, like the foundation of your house or the roots of a tree. But the opposite is true for riding. Comfort And Stability What works well on a paddock-stand doesn't always transfer to real riding. Aftermarket rearsets, which can be adjusted (or which are manufactured) too far up, back, forward or down is an example. In the paddock they feel racy; on the road or track they can fatigue the rider. The fatigue comes from the rider's core not being correctly supported. This causes him to be off balance. Off-balance generates extra effort from muscle tension and poor joint alignment which in turn hampers accurate control manipulations. Awkward looking body position is what you see. Riders often accept or try and work around this, without realizing its negative impact on their riding. Simply Complicated Through research and coaching of tens of thousands of riders of all skill levels, 58 separate elements which influence our body positioning have surfaced. Seemingly simple things such as too tight a pair of gloves or leathers can affect all the other elements. Once the 58 are corrected and integrated, the rider has many more options; opening doors to a wide range of fun, efficient and, you might say, elegant techniques. All of our coaches have been thoroughly drilled on what each of the 58 are and how to correct them. © 2014 Keith Code, all rights reserved. This article may not be reproduced in any form without the author's consent.
  9. 3 points
    Your collection of data and research shows you are barking up the right trees. Here's some more data regarding tires: Per the Dunlop engineers tires grip in 4 ways: 1) Adhesion--the temporary chemical bond between the tire and surface. 2) Keying--the tire deforming and filling in all the nooks and crannies of the asphalt or squishing into the depressions. 3) Abrasion--the tire tearing from itself or wearing away. 4) Hysteresis--the energy storage and return by the rubber and partial conversion to heat. The first two can be looked at as static properties and the last two dynamic properties in my opinion. I'm still learning on all this stuff and when talking to the tire engineers, they don't have all the answers either. Heck, aviation engineers still can't all agree on exactly how a plane flies through the air!
  10. 3 points
    It sounds to me as though you might not be taking into account how suspension affects tire grip. Are you, for example, assuming a completely rigid connection between the wheel and motorcycle, with no suspension action and a non-deformable tire? Are you assuming that the grip of tire to pavement is constant, and is at the theoretical maximum friction of rubber to asphalt? There is more grip available when the bike is upright because the suspension is more effective at keeping the tire consistently in contact with the pavement. There is a theoretical maximum friction that you can calculate but in real-world riding, the pavement is not perfectly flat or perfectly consistent so the theoretical grip (calculated from formulas, with assumptions and simplifications made - usually a LOT of them) is NOT the same as actual real-life grip. Does it make sense to you, in your actual riding experience, that you have more grip when the bike is more upright than when you are at maximum lean angle? If so, does it follow that as you stand the bike up, you HAVE more grip available, so that even though you were at the max (for that lean angle) a millisecond before, you now have MORE grip available because the bike is coming up, and any tiny slide that would have begun from the countersteering effort would be halted by that additional grip? One must be very careful when attempted to use physics formulas to calculate grip. There are MANY factors that are ignored, assumed constant, or simplified in order to make formulas or concepts easier to understand, but trying to apply theories that don't take into accounts the LARGE number of variables present in real-world riding can lead to some confusions. You can find numerous examples on this board.
  11. 3 points
    I do not understand this statement, can you restate it or explain it more? If I understand your question about how to exit a corner, you are talking about coming out of the corner onto a straight(er) part of track, and you are asking how to change the arc to put the bike in a straighter line, is that right? If so, then the answer is yes, you would counter steer to bring up the bike. The momentary instability caused by the countersteering effort is overcome right away by the increased grip afforded by getting the bike more upright (primarily due to your suspension being able to work more effectively). In other words even if the front tire DID slide a little, it would recover, and in fact that is often how riders recover when a tire starts to slide - by standing the bike up. (Sometimes they recover by just staying loose on the bars and the tires regain grip either because they reach better pavement - like a slide on a greasy spot in the road - or because the bike has slowed some.) Keep in mind, though, that the rider must make a reasonably controlled steering input - a death grip on the bars that restricts bar movement, or a rider pushing on BOTH bars, or an extremely rough bar input could indeed cause a fall.
  12. 3 points
    Interesting topic. Three things that came to mind while reading through the posts: 1. Many moons ago, Roberts sr had trouble going fast enough around Suzuka. Instead of continue circulating, he went back to the hotel and had a think. A few hours later he returned to the track and said he had found 2 seconds. Hei proved it by going 2 seconds faster. 2. Darren Binder, Moto3, says he has no braking points, he brakes when those around him does. He's fast, but cause a lot of havoc and crash frequently. 3. Rossi, and others, often try a fully new and untested setup before races when they haven't found a competitive setup during practice. At least in the case of Rossi, it seems to pay off more often than not.
  13. 3 points
    Practice till you can't get it wrong, I'd just heard this in another arena (pistol shooting), but like the idea!
  14. 3 points
  15. 3 points
    I see a second steering input also. Could be that the roll on was already starting as you leaned it that extra bit, or maybe you were already near the limit (for those tires) and the extra bit of lean was enough to break it loose. I can't hear it well enough on the video to tell for sure but that extra lean combined with some throttle application could definitely have caused the rear to slide without warning.
  16. 3 points
    Here is some info from Dylan that you might find interesting: Dunlop just released a new sportbike tire, the Q4. This tire is different from what many think it is. It is NOT an improved Q3+ but rather a whole new category of tire. Its purpose is to provide a street legal tire with excellent grip, no need for warmers, that is at home on the track or on your favorite twisty road. Essentially it fills the gap between the Q3+ and the street legal race tire, the GPA Pro. So the progression looks like this: Q3+. Best all purpose tire. Harder center band for commuting, with sides well suited for cornering. Q4. Best for trackdays and canyons/twisty roads. Warms fast, less sensitive to pressure settings. Single compound across entire tread. Any loss in overall mileage is gained in grip compared to Q3+. GPA Pro. Essentially a race slick with grooves. Warmers strongly recommended particularly when cool and pressures checked and set before riding. Street legal. Poor choice for commuting but good for twisty roads and very much at home on the track. Slicks. Pure track only tire. Warmers strongly recommended with pressures checked and set before riding.
  17. 3 points
    Let's touch on one thing: bike doesn't turn as well when the throttle is on, even just maintenance throttle. When off throttle, bike weight is forward, more on the front, steering angle is steeper, wheelbase is shorter--the bike turns better. Does anyone know a single turn where braking is done, then gas on, then bike turned,? As mentioned earlier by trueblue550 (Streets of Willow Springs) there are series of turns where the throttle is stopped for a moment to complete the steering (T 4-5), or where rolling it on puts the rider too wide for the next turn in point (T5-T6). These are situations where there is a series of turns, the following one dictating the exit of the previous turn.
  18. 3 points
    I'll take a swing as well. I may be misreading the question but I don't believe it is an "either or". I believe the answer is "yes" to both sides of the question. First, I think the vast majority of today's motorcycles are designed for their intended use. In the broadest sense think dedicated dirt bikes, trials bikes, track bikes, touring bikes, etc. Their frame and steering geometry, suspension set-up, basic rider ergonomics, engine choices, etc., are all designed with a purpose or specific rider use in mind. However they are also designed within the limitations of today's technology and materials science knowledge, plus the economic realities and limits of what consumers will pay for a given motorcycle's capabilities. With regard to "do we need to do something to keep a motorcycle in its operating envelop", my initial reaction is to say we do it every single time we ride when managing things like throttle and acceleration levels, braking force, lean angles and traction limits for the specific riding situation we happen to be in. And we all know what can happen when we exceed an operating envelop. Just an add-on thought to this. What I love about many of today's motorcycles is how technology (e.g. ABS, traction control, engine braking, wheelie control, slide control, various riding modes, etc.) is being leveraged to help us safely stay within a motorcycle's operating envelop, AND that we can adjust the parameters of the envelop for our various skills and capabilities. I can't even imagine where motorcycle tech will be in another 20 years, but I know it will be fantastic! I've heard people say we're in the golden age of tire tech, but we might even be able to say that about the software / sensors / ECU technologies of today's motorcycles. Dave
  19. 3 points
    In this article, Keith describes what HE needs to do, to make riding improvements, this article has been pivotal for me in my riding. I carry a copy of it with me to every track day or school. I went to the Articles section to look for the link to it and noted there are several other articles about Rider Improvement or Isolating Barriers, etc. a look through the Articles section may help you find some of the answers you seek.
  20. 3 points
    MotoGP riders are typically trying to dial up as much engine braking as possible. They can also dial it in or out for specific turns by GPS. If you are riding a track that is very "stop and go" with a lot of braking zones, I would dial it up. If it is a flowing track with transitions, I would use less engine braking so the bike does not pitch forward if you feather out of the throttle in a transition.
  21. 3 points
    Hi JP, Your questions are good. There are a number of factors that come into play, and one answer won't work for all turns/situation. The one that will give the most problems is increasing throttle and lean angle together, that's usually a big no-no. Have you read any of Twist of the Wrist 2, or seen the video? That will give you some great guidelines. Best, Cobie
  22. 3 points
    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.
  23. 3 points
    I have almost no experience with V twins, but there are some things that can help with that problem in general, that might apply to your bike. Have you tried turning up the idle? This is a common thing to do on a track/race bike so the rpms don't fall as much when off the gas and it can really help make the roll on smoother. It does have the effect of taking you into the corner a little quicker so be cautious when you first start riding it that way. On an inline 4 I believe typical advice is to turn it up 500 - 1,000 RPM, but you should Google recommendations for your bike. What gear are you using entering the turns, are you a gear lower than you need to be? Sometimes just entering a corner in a higher gear makes enough difference in smoothness to be worth it, especially on a bike with a lot of torque that can handle coming out at a lower RPM. I assume you have checked for play in the throttle and cable, to eliminate any jerk or effort from just taking out the slack. An aftermarket tune is, in my opinion, a great idea. The other suggestions above don't cost anything, and this does, but you can get a really nice improvement in throttle response from working with a tuner and a dyno. Tunes that I have done on my bikes have yielded performance in power but MUCH more benefit in the area of getting better throttle response. (Better meaning, working how I wanted it to work!)
  24. 3 points
    Yes, it could be that you are at your desired lean angle (steering action complete) but not yet pointed in the direction you want the bike to go. Sometimes there is a pause as you wait for the bike to come around onto the desired line. Turn 2 at Laguna is a GREAT example of a turn where it is VERY easy to get on the gas a little too early in the second part of the turn and miss the apex - which is punished immediately upon the exit because it is tight and forces the rider to make a correction to avoid going off track. It is also really easy to come on the throttle a little bit too early when chasing a faster rider, trying to catch up, or keep up.
  25. 3 points
    I went to Thunderhill West this past weekend with my dad. I was doing level 4 for Saturday and Sunday. Saturday felt great, I learned the track, I felt fast, and left feeling like I could get through the track comfortably. Sunday came and for some reason it was a different story. I went off track three times and would let my SR's take over in Turn 1. I could not figure it out. I felt like I was only adding 10-15 mph down the straight just to up my pace. Why was this such a big deal?! First of all, after consulting with Johnny, adding that much speed is too much. I needed to add it gradually, 1 mph at a time even. Gerry was my coach for Sunday. We found that my vision was hindering me. By adding that much speed, I had to PLAN for my turn point earlier. I just kept focusing on the turn point itself and by the time I hit it, I was already beyond it and therefore turning in late with a new sense of speed....I would panic and become stiff on the bars. Gerry coached me to look WAYYY ahead. Go at my normal pace, and look wayyyyy ahead at Turn 1. I did and suddenly the track felt slower. I felt like I was scooting along on a pedal bicycle down the straight and going into Turn 1. I got my lap times recorded for Sunday. My fastest lap time of a 1:40 was during my second session, when I was still affected by my vision. Surrounding that time was a bunch of 1:50's or even 2:00 +. Crazy variance..... After listening to Gerry and using my vision to slow things down for the last session, my lap times were consistently 1:43 1:44 and staying in that range. I know it is slower, but the consistency is important. This shows me that if I can stay consistent, I can begin to work on my speed. I was doing the same thing every single lap and talking to myself in my helmet, "2 step, no greys." This meant use the two step and look way ahead. No greys meant to not hit the gray curbing at all and to look 4-inches to the side of the curbing so I could place my front wheel there. I wanted to thank Gerry and Big Andy for their coaching on both days as well as Johnny for his consulting between sessions both days. We came up with a plan every time and after execution, the results were showing in timed laps as well as overall confidence on the track. Gerry also taught me how to use my peripheral vision to sense movement. This would help with passing others and my goodness it made such a difference to my whole experience!!! I was passing other riders safely and with enough space and speed. It really changed things. I cannot wait to implement this at my next track day/ race. I will take time today to write down my plan for my home tracks and how to approach different corners. I really like that once you leave a track with CSS and go to your home track, you can apply what you learned to your home track. You did not have to sit there and say, "okay I learned the track with them...why don't them come here so I can learn my track with them?" It is more like, "OH! This turn is JUST LIKE turn 2 at Thunderhill! I know how to do this!" Thank you all for the great weekend and learning. We will be back and my dad wants to do Level II! The photo below is of my dad and I. I caught up with him for the photo op to look like a doofus (I am on 21 and he's on 22).
  26. 3 points
  27. 3 points
    Most discussions of steering and "weight shift", "loading" and "helps it to steer" are riddled with illogic, and the people discussing will not reach a conclusion predicated on so many errors in thought. Rather, going to the basics of logic is the best way forward lest they get entangled permanently in confusions. Forums have become a popular platform to air ones flawed thought process, while other visitors try in vain to overhaul their whole logical approach to problem solving. Not saying I've got logic down myself, but some statements and articles have so many flaws, it's like: "where do we start?..." and just skip it. Remember when you have contrary facts, one or both are false. Some things to consider: https://en.wikipedia.org/wiki/Consistency https://en.wikipedia.org/wiki/Validity
  28. 3 points
    Here's a short TV spot about CSS. Courtesy of Superbike Planet
  29. 3 points
    A couple of other things to be cautious about. 1. Puddles. Not only because of the hydroplaning potential. Hit one at speed and all the water in the puddle nearly instantaneously will soak you and add lots of weight to you. 2. Tar snakes and patches. Not all traction is created equal. Tar snakes will cause a lot more traction issues when they are wet. Some patched areas have more or less traction than the main part of the track. 3. Visibility. Visor fogging (easily fixed), Mist from other bikes, fog and rain on your visor can reduce visibility. Use a clear shield at all times to avoid this and preferably a clear windshield on your bike to maximize visibility. The straights are a gigantic wind powered windshield wiper for your helmet if you stick your head up in the air stream and move it from side to side. 4. Slippery when wet. Controls, pegs, tanks and other parts of the bike are not as easy to hold onto when your bike is wet. Be aware.
  30. 3 points
    Personally I love riding in the rain. Less traffic and at the end of the day it's like having your own private track when everyone packs up and leaves early. When other riders are angry and horrified about the R word I'm thinking "heck yea"! Some of the things that change in my riding in the rain. 1. Braking. Earlier, lighter, longer. Stretch out the braking zone and leave yourself a buffer just in case. 2. Lean angle. Less is more. You stay on the fatter part of the tire and maintain more traction. Hang WAY off the bike to reduce lean angle. The more you hang off even at slower speeds keeps you on the more stable part of the tire. 3. Line. It's critical to use ALL of the track available to flatten out the corners as much as possible. 4. Less aggressive quick steer. I have found that you absolutely still can quick steer in the rain if you stay reasonable with it. I worried the heck out of a CSS coach when he assigned me the quick steer drill in the rain. I performed the drill too. I even got a hug when I came back in one piece. 5. Throttle. You have to be a lot easier on the throttle especially when the bike is leaned over. On "analog" bikes once the bike is straight up and down you can use the throttle to "sample" traction. Give it gas and you can feel where the tire wants to spin just a bit. That is the fine line of where the traction ends. Don't cross the line especially when leaned over. (I would approach this with caution!). On bikes like the S1000RR in the right mode the bike will protect you for the most part on the gas. I find that I prefer sport mode or higher in the rain but rain mode is more protective and best to start out with. 6. Smooth counts. Abrupt and sloppy inputs that are ignored because of mega grippy tires are not tolerated at all by the bike in the wet. Stuff to watch out for! 1. Curbing. It's fine to run over curbing in the dry but in the wet that stuff becomes really slick. You have WAY less traction than you do in the dry on painted parts. 2. Panic. If you end up overdoing it don't panic!!!! With less traction the bike is much less willing to be forgiving for sloppy and abrupt inputs. If you enter a corner too fast just extend your braking past the optimal turn point and use the track you have available. Bring the bike down to a manageable speed and turn where you can. Yes you essentially "blow" the corner but by using the track you have you keep it on the pavement. 3. Tires. It's COMPLETELY true what was said about tire temps earlier. Your tires won't maintain temp. Not only are you dealing with the slick surface created by a wet track you are doing it essentially on cold tires. I set a cold pressure and leave it there. You can even experiment a bit with dropping the pressure but I'm not really sure it helps much and can potentially make the bike feel a bit mushy and imprecise if you overdo it. You still won't get a lot of heat in the tires. 4. Your physical condition. Riding in the rain seems easier but you do still get tired. Since you aren't sweating like crazy the fatigue sneaks up on you. I rode every single session of a wet track day only to figure out during the last session that I was a lot more fatigued than I realized. This fatigue can be both mental and physical. Stay sharp!
  31. 3 points
    The short answer: you have to work up to it and feel it out. The longer answer: Testing the grippiness of your tire must be done gradually, the idea is to increase lean angle gradually so that if the tire begins to slide there is some warning and opportunity to save it. The most pro coaches I have talked to on this advise gradually adding a little more lean at a time (corner after corner, or possibly even in the same corner if it is a long one) to feel out the traction, as opposed to just whacking it over to maximum lean and hoping for the best - because if you go too far too fast you will not have enough time to "sample" the traction and see how it feels, and know when you are approaching the limit. Some tires will have a specific feel to them when they are cold: the Dunlop slicks, for example, have a tendency to make the bike want to stand up in the corner and that is a good indicator that they are very cold. The carcass is stiff and reluctant to flex so when you lean into the corner it resists and sort of pushes the bike back up. Some other tires just feel a bit "wandery" in the corner, like they are sort of weaving around slightly, instead of feeling planted. If you have ridden in rain or ridden dirt bikes in the mud, you can recognize the feel of little slides, and little slides like that are your warning that you are at about the limit of traction for the conditions and the tire needs to warm up more before you can lean over any farther. It is a great exercise, when opportunity presents (winter is coming!) to pay VERY close attention to how your tires feel when stone cold, to develop a sense for it with your own bike and your own tire brand/model. It is difficult to quantify how long tires will take to warm up because it depends on tire type, air temp, track temp, wind conditions, how hard you ride, etc., so the best solution I know of is to feel it out carefully.
  32. 3 points
    I have translated it - let me know if it is OK to read, or I can share a link to my document for those interested. Who leans that far? Where are the limits? And what are the differences between street bikes? We compare bikes around a skid pad: Supermoto, Naked Bike, Cruiser und Superbike. We have also discused with experts and tried qualifying tyres from WSBK to see how they differ from street legal sport tyres. Why do we lean? Without lean to counter the centrifugal forces, the bikes would simply fall over. Leaning against the forces the correct amount keeps the machine and rider in balance. For a given radius, the faster one rides, the more one must lean. Or for a given speed, the smaller the radius, the more one must lean. How far can we lean? Sport bikes are generally limited by grip, or friction. With good tyres on a good road we typically have a friction quotient of one µ. This means we can theoretically lean 45 degrees. If you lean further, or you try to slow down or accelerate, you will slide. However, we know it is possible to achieve greater angles of lean. How? Because very grippy tyres and a grainy road surface can interact like gears. That’s why in MotoP and WSBK we can now see bike lean angles as high as 62 degrees. With the rider hanging off we can even see combined lean angles beyond that. What is that- different lean values? Corner master Jorge Lorenzo show us the difference between bike lean and the third lean. Lean angle isn’t always lean angle Basically, we talk about three lean angles. The first one is the effective lean angle. This is a theoretical value and is calculated from the speed and the radius of the corner. This counts for every bike and every rider. But this theoretical value for effective lean angle is based upon infinitely narrow tyres. Now to reality. Imagine watching a vertical bike from behind. Pull a vertical line through the bike’s centre line, the tyre and to the ground. This is where the contact point is as well as the CoG. Now place the bike on its kickstand. Now we see that the contact point between tyre and road has moved to the side somewhat because the tyres are not infinitely narrow. The more we lean the bike, the further away we move the contact point away from the bike’s centre line. If we draw a line through the CoG and both the centre line as well as down to the contact patch, we create a triangle. The angle between them is the second lean. This is the added lean required to corner at the same speed as you would have been with infinitely narrow tyres. This also show that wider tyres require more lean narrower tyres. Lorenzo shows us the difference between the bike’s lean and the third lean. With his extreme hanging off the rider is leaned over far more than the bike. The combination of the two - bike and rider - gives the third angle of lean, the combined lean. Bei 62 degree bike lean we can get to an extreme combined value of 66 degrees. What can production bikes muster? We take 4 different bikes and try them on the skid pad sitting in line with the bike, pushing the bike down and hanging off. We then measure bike lean, calculate combined lean and measure cornering speed. What gives the greatest speed? Lean angle with the Husqvarna 701 The skid pad has a diameter of 55 metres. Upright lean is 47 degrees, speed 57 kph. In typical sumo-style, pushing the bike down while leaning out, we managed 57 degrees bike lean and a speed of 62 kph. The combined lean is 51 degrees. This is the biggest difference in the test (6 degrees), a result of a light bike, high CoG, high and wide bars, narrow seat, low set pegs. Final attempt is hanging off, and we get the exact same values of 62 kph and 51 degrees combined lean. The bike is only leaning 46 degrees. So the speed is the same, but pushing the bike down sumo-style bring some advantages; more bike control and easier to catch slides being the predominant. Ducati Diavel, Cruiser & Co. Unlike for sport bikes, cruisers are limited by dragging parts when it comes to possible lean angles. With 41 degrees, the pegs are in contact with the asphalt. This will be the same regardless of what style is used. This gives us a fantastic opportunity to compare cornering speeds between the various riding styles. Sitting up gives 50 kph, pushing down 47 kph and hanging off 53 kph. MotoGP bikes can actually accelerate harder when leaned over than in a straight line. While maximum acceleration on level ground is limited to about 1g, a MotoGP bike can accelerate at 1.2g when leaned over 45 degrees! For street bikes on public roads, 45 degrees means zeron grip left for acceleration. A modern street legal sport bike outfitted with racing tyre and circulating on a grippy race track can give up to 1g of acceleration when leaned over at 40 degrees. Cornering with the Honda Fireblade First we ride on the stock Bridgestone S20 “G” tyres. Hanging off gives 61 kph and 48 degrees of lean for the bike, combined 51 degrees. What difference does qualifying tyres make? WSBK Q-tyre, straight from the heaters, has tremendous grip and feedback. We do not give up until the Fireblade gets “floaty”, a sign we are nearing the limit. With the bike leaned over 53 degrees we reached 65 kph. Combined lean is 55 degrees with the rider hanging off. Why not faster? The asphalt was cold (less than 10C / 50F) and the asphalt not overly grippy. Add a slight negative camber and the limits were like that. But this was the same for all tyres. The problem for the Q-rubber was that they lost their heat rapidly, losing grip in the process. A Pirelli-technician explained that the racers don’t lean further on Qs, but they have more grip available for braking and acceleration. Enough to give about a second lower lap times. Two laps, though, and they are mostly gone. Cornering with the BMW S 1000 R Standard Pirelli Diablo Rosso Corsa allowed 59 km/h when hanging off, with 47 degree bike lean and 50 Grad combined lean was good, but better results were limited by grinding foot peg feelers and gear shift lever. Foto: www.factstudio.de Husqvarna Supermoto 701 Sitting straight made the rider feel uneasy, which limited lean and cornering speed. Foto: www.factstudio.de The Sumo-Stil made the rider feel at most comfortable. Sliding tyres and grinding parts set the limit. Foto: www.factstudio.de If the rider had been able to hang as well off as he was at pushing the bike down, he could have cornered faster. Foto: Archiv Tyre width and CoG Wider tyres demand more lean for any given corner speed. The same goes for lower CoG. The difference between the tall Husky 701 with relatively narrow tyres and the low Diavel with its ultra-wide tyres was 3 degrees when doing 50 kph around the skid pad; 38 for the 701 and 41 for the Diavel. Foto: 2snap Lateral acceleration and lean While 45 degrees of lean gives 1g, 60 degrees give 1.7g, which isn’t the same as going 1.7 times faster by any means. Foto: www.factstudio.de Ducati Diavel A good way to see what the different riding styles can bring. Foto: www.factstudio.de Looks weird, feels weird. Foto: www.factstudio.de Feels much better than pushing the bike down!Foto: Archiv Der Kammsche Kreis This shows how much grip is left to brake or accelerate or steer at various lean angles. If you are leaned over to use half the lateral acceleration, you have 85% grip left to other forces (green arrow). The red arrow indicate that you have only 10% grip left to do anything else than circulate. Grip through the gear effect. Mikrorauigkeit (red) [micro coarseness], with spikes between 0,001 and 0,1 Millimeter is especially useful in the wet, while Makrorauigkeit (green) [macro coarseness] between 0,1 und 10 Millimeter make the difference on dry roads. Foto: Archiv Contact patch with a 180/55 sport tyre with a racing profile at 48 degrees of lean. 38 square centimetres contact area. Typical contact patch is that of a credit card. Public roads are more slippery than tracks, particularly in the wet because the surface lack Microraugkeit. Cold rubber, especially with sport tyres, can cause the tyre to slide on top of the asphalt instead of forming around it. Hence sport rubber is worse than touring rubber below a certain tyre temperature. Karussell around Nürburgring is bumpy and can be taken with 58 degrees of lean. However, thanks to the sloping surface, the angle between the road and machine is just 33 degrees. Lean and speed The Fireblade on WSBK Q-tyres managed 55 degrees of lean and 65 kph. If we theoretically put Marquez on the same skidpad with a combined lean of 66 degrees, he would have circulated at 78 kph.
  33. 3 points
    The logic in getting more weight on the front, as I understand it, is that more pressure/weight on the front tire will increase friction (friction increases with weight) and also flatten the tire out more, making the contact patch larger, which doesn't increase friction directly (friction is not dependent on area, just weight) but CAN help the tire because too much pressure in too small an area can (I think) overheat the rubber and reduce the coefficient of friction, which WOULD reduce the overall grip. (Note - this is me giving you my own understanding, this is not superbike-school endorsed info.) Getting more weight on the front also can tighten up your steering by compressing the forks - but you can also get a similar effect with hook steering or changing your geometry or suspension settings. So that all works well for turn ENTRY, however once have turned the bike and have reached your desired lean angle and are pointed in the direction you want to go, if you don't get on the gas you will just keep slowing down. The best scenario for traction once you DO roll on the gas is: 40/60 weight distribution. Thus, the throttle control rule, "Once the throttle is cracked on..." So, the way I look at it, is while you are still slowing down and getting the bike turned, the weight on the front is a good thing (to a point - obviously using too much trail braking while turning can exceed your front tire traction), and once you are back on the gas, 40/60 is the way to go for best stability (we are no longer making lean angle changes at that point) and traction. Does that make sense? Do you remember from level 1 exactly WHEN you are supposed to START rolling on the gas?
  34. 3 points
    This is the way I understand throttle control rule number two in Chapter 6: Fine modulation of the throttle helps you read the forces that you feel more accurately. The advantage of that is that your entry speed will be more consistent and appropriate than if you grossly decelerate in a hurry (charging the curve), just to find out that your entry speed (at the end of that precipitate deceleration) is lower than it should be (because your senses were overwhelmed, you are erring on the safe side of entry speed). The error about the entry speed is more significant for any fast-entry turn, especially due to the aerodynamic drag explained by Hotfoot above.
  35. 3 points
    Cool story. Read this: https://www.scientificamerican.com/article/the-bicycle-problem-that-nearly-broke-mathematics/#
  36. 2 points
    I have been told that weighting, or rather pressing down on the outside peg allows you to corner faster and safer, as it encourages you to put your head and shoulder weight, and not your butt, inside the turn (aka: kissing the mirrors), which requires less lean angle in a given turn/curve. (Your upper body weight leaning into the turn replaces some of the bikes weight it would use in the lean, requiring less lean angle on the bike) Ive taken turns where it seems the bike stays almost upright, and I'm able to hug the inside line nicely in the apex of long curves. It helps as well as it puts an outside downward force to the rear tire for stability/traction. I havent been riding a long time, but I have been testing taking turns in this fashion, and it definitely seems to help me.
  37. 2 points
    You are correct, but only if such motorcycle is neutral steering-wise. As you know, many bikes have a natural tendency to either understeer or oversteer (if the rider releases the handlebar while the bike is leaned on a curve). Those tendencies depend mainly on geometry and profile of tires. The front contact patch of an understeering bike will "feel" less lateral force when coming out of a lean/corner as it had been forced to over-steer during the curve. In the steady conditions that you have described (while keeping zero angular input on the steering), the sliding force on each contact patch remains constant and it depends on the square value of the forward velocity of the bike and the inverse of the radius of the trajectory. As you properly have explained, any counter-steering input will instantaneously increase the value of that lateral or sliding force (especially for the front contact patch). The lean angle (and linked lateral forces) can remain constant along a curve, but real conditions of the road make it maximum only intermittently. Maximum grip or friction depends on the force that is normal or perpendicular to the surfaces in contact. The undulations of the road and the instantaneous accelerations that add to and subtract from the natural acceleration of gravity, induce a fluctuating amount of that normal force or available maximum friction or grip. Each tire has more available traction each time it rolls over a crest: that instantaneously increased normal force deforms the tire and partially compresses the springs, which push and accelerate the rider and the rest of the mass of the bike and fluids upwards. Exactly the opposite happens when the tire "falls" into a valley of the track's surface: less available traction for a fraction of a second. In other words, assuming a perfectly horizontal traverse surface of the curve (no sectional slant, slope or crown), which makes the value of the normal force that induces grip equal to the value of the weight supported by one tire, the undulating nature of that surface will make that tire and its suspension alternatively support more and less weight than normal (for a perfectly ideal flat surface). Hence, more that having a sharp value, the available grip of each tire constantly rises and falls / pulses / swings / oscillates around an average value. Similar effect (although at much higher frequencies) is produced by the vibrations coming from the rubber compound of the tire when supporting strong lateral forces (getting deformed, twisted, overheated, sheared) and when crabbing or sliding off the trajectory (while keeping grip). At microscopic level, things are changing at a very rapid rate and the surfaces are gripping each other and letting go in a very rapid sequence. Consider also that all the disturbances described above induce minimal steering inputs. Because of the trail of the front tire, while it is leaned, any close to vertical force has a perturbing effect (torque that is equivalent to a sideways force times trail distance) when the bike is in vertical position. A torque is induced into the steering, which can be over or under-steering, which significantly modifies the radius of the trajectory, which momentarily changes the magnitude of the lateral forces. Hotfoot's excellent post has perfectly explained the Physics of real life.
  38. 2 points
    I recognize that I’m almost exactly 3 years late to this party, but the past three weeks I’ve been using the forum search function and scrolling through pages of posts on a tire heat/traction research assignment from Cobie, and this thread is definitely the best I’ve come across yet. Cobie, you’ve done a great job of engaging and drawing participants out; there’s been a symbiotic contribution-response at almost every point along the way. The only thing I can add is an over-simplification of the topic, but based on the posts, I believe we all understand it: ’Train until you get it right, Practice until you can’t get it wrong” This encompasses the training of a new technique, and the refinement of that technique into a solid repeatable action (perhaps unthought).
  39. 2 points
    For sure this is difficult to judge, for anyone. Laptimes are a measurement, and being able to achieve very CONSISTENT laptimes is a good indicator that a rider is well in control of their lines and speed and that the error rate is low, all of which indicates good riding skills. Seeing one's own laptimes come down on a given day at a given track is a good indicator that the rider is figuring out the track and making improvements. Being able to stay relaxed and ride without errors and without exhaustion is a great improvement, and something the rider can observe relatively easily for themselves. However - trying to compare laptimes to other riders may not be very meaningful unless you are racing . At track days and especially at schools, riders ARE, by definition, working on making changes and sorting things out so their laptimes can vary considerably from actual go-for-it race pace times. At CSS riders are asked to ride at around 75% pace so that they have enough free attention to make observations and changes in their riding, plus there are formats and drills and sometimes different track configurations (compared to how other organizations run their day) so a school day laptime may not mean much when compared to a race laptime, or even open track day times. So if you are looking at a CSS laptime and trying to decide if you could race at that track, it may not really translate. Going out and doing a new racer's school at that track (unless you already have a race license?) would allow you to get a sense of whether you can be competitive, and most of them do a mock race at the end of the day, which is fun and instructive, and most schools will be able to tell you if your laptime is acceptable for you to race there. Racing creates a whole new set of challenges - the track pace is fast and that will immediately push you to find places where you can go faster, and likely make you push yourself enough to reveal next areas of improvement in your riding. I think most of all you will need to decide your personal priorities for improvement, THEN figure out how to measure. What are your goals as a rider? Are you interested in being calmer on the track? Safer? More accurate? More consistent? More comfortable? Do you want to be able to learn new tracks faster? Do you want quicker laptimes? Do you want to ride in A group at your local track? Do you want to start club racing? Once you have your own goals set, finding ways to measure that should be easier. Interesting question about whether it changes based on the track... I guess my answer would be that there are certain skills that identify a skilled rider. Consistent entry speeds, good control of the bike (accurate, effective steering with steering rate appropriate to the turn), secure, locked-on body position, relaxed upper body, and good visual skills come to mind. One can watch a skilled rider on a new track, and they may be riding slow and figuring out lines but you can see the skills are there and know that once they get the lines figured out they will be able to ride consistently and quickly. You can also go to an open track day and see someone getting good laptimes (by pushing really hard) but leaning the bike over too far on the gas, exiting corners at the ragged edge of the track, making steering corrections, stabbing the brake, hanging off too far and steering ineffectively, making rough downshifts, etc. and see that they may be going pretty fast but they are lacking some really important basics and although they know the track well, they are hitting some big barriers that will hold them back and/or cause them to crash if they try to go any quicker.
  40. 2 points
    I notice that it is very hard to get the actual character of the track from seeing it on TV. Hard to perceive the elevation changes, hard to see the changes in camber and surface, and the abrupt changes in camera perspective can make it hard to grasp the flow of the track. I also notice that I am amazed by how much the bikes slide around, and wiggle under hard braking, and how rough some riders can be on the controls while others are silky smooth. When I watch videos (especially on-board videos) of amateur racers I am amazed by how many errors some riders make in races. Riders that are fast, judging by their laptimes, but make a lot of mistakes; it would seem surprising that they don't fall down more often - but then sometimes I find out they DO fall often. It certainly seems possible to pick up some incorrect ideas or not-useful information, for example I sometimes hear announcers throw out some thoughtless comment or platitude that is really not applicable and could be confusing if you tried to really take it seriously. On the other hand, seems like you could learn a lot about preparation and race strategy, tire wear management, and race rules by watching races, by seeing what happens to riders that are late to the grid, or overwork their tires in the first part or a race, or choose the right or wrong tire compound, I find that stuff quite interesting.
  41. 2 points
    Ha, 27 in a 60 year old body...I don't think I made it past about 18 in my emotional development...that or I've been in my mid-life crisis for about 30 years CF
  42. 2 points
    The book that you have mentioned has the answer to your original question: "What makes the bike turn the same as it was leaned more without hanging off? It is explained in Chapter 3: Less lean angle requires more effective steering angle in order to keep the same radius of turn (please, see figure 3.18 of page 3-13): "Increasing lean angle tends to increase the effective steering angle." It is a simple geometrical problem, there is no need to complicate it with camber thrust, slip angles, etc., because the magnitudes of the forces of cornering and the dynamic lean angle remain the same, either or not you hang-off. The chassis reduces its lean angle when the rider hangs-off while cornering, which changes the relative geometry among the three planes: the ones containing the rear tire, the steered front tire and the curve (track surface).  You may want to do the following experiment: Fill up a wide recipient with water (the surface of the water will work like the plane of the curve). Make a central 10-degree bend in a small rectangular piece of cardboard (one side will work like the plane containing the rear tire and the other side like the plane of the front tire). Keeping the bent edge and both sides vertical, deep the piece of cardboard into the water. Looking from above, turn the cardboard just like a bike would lean over to turn and note how the angle formed between both lines that intersect the surface of the water and each side of the cardboard gets bigger as the lean angle increases. That angle is the effective (or kinetic) steering angle, which would force the bike to turn tighter (reduced radius of turn) if the rider would not compensate for this phenomena by steering a little less. If that experiment still does not convince you, we could use the following well stablished formula: Radius of turn = [Wheelbase x Cosine of chassis lean angle] / [Steer angle x Cosine of caster angle] As wheelbase gets a little bit smaller and caster angle remains constant, when the rider hangs off while cornering, the cosine of the chassis lean angle increases (example: cos 45=0.707 and cos 40=0.766). That change would increase the radius of turn some, making the bike run wide respect to the desired trajectory. In order to avoid that from happening, the rider must compensate by increasing the steer angle a little. Another geometrical way to analize that: Imagine a perfectly vertical line running underground by the center of the circular trajectory of the motorcycle. Disregarding slip and camber thrust, the extended axis of both wheels must intersect with that vertical line. As those wheels are leaned more, the point of intersection moves deeper into the ground, which reduces the angle formed between the extended axis of both wheels. Hence, the steering angle must be reduced some in order for the bike to keep tracing the same circular trajectory.  A leaned motorcycle will always have an effective steering angle that is smaller than the one for a 4-wheel vehicle describing the same curve.  The exercise of Motorcycle Gymkhana is a different solution to a problem that is different: make the tightest quick turn around a cone. The maximum speed at maximum lean angle will make you slower in this particular case, try that experiment as well. Since speed must be much smaller than during normal Superbike track cornering, the smallest radius of turn of the rear tire is the key to turn the bike 180 degrees as quickly as possible. For the same reason explained above, the Gymkhana rider wants the chassis to be as leaned as possible during the slowest section of the tight turn. At full stop lock of the steering, the radius of turn (and the circular trajectory of both tires) will be smaller as the chassis lean angle increases: there is a greater effective steering angle. Lock the steering of a bicycle at a pronounced angle and push it while at different sustained lean angles for each completed circle and you will see that the smallest circle corresponds with the biggest lean angle. For the above formula and description of angles, please see "Steering angle" here: https://en.wikipedia.org/wiki/Bicycle_and_motorcycle_dynamics
  43. 2 points
    I did a 2 up ride with a pro racer when I was still a brand-new track rider. It scared the hell out of me! I got on, he told me to put one hand on his chest and the other on the tank (no handholds on the tank back then) and took off. He was moving all over the place, hanging off for the corners, and accelerating and braking hard - I was sure I would fall off. After about 3/4 of a lap I started to think I'd be OK - then as we started the 2nd lap he yelled over his shoulder, "Ok, I'm going to go faster this lap!" and I yelled "No!" but he obviously didn't hear me because he DID go faster. What did I learn from it? Well, I got a new perspective on how fast one COULD (potentially) enter a corner, and how close a pro rider really does get to the inside edge of the track, and how HARD you can brake. I was, at the time, such a new rider that it all seemed somewhat unreal; I probably would have gotten more out of it if I had done it later when I had more experience. But, I'll be honest, I have no desire to do it again. I haven't done much riding (or fast paced driving in a car) as a passenger - I would much rather be driving! Going at race pace with someone else in control is definitely a scary experience, I am always amazed and impressed by those people that ride in rally cars as the navigator.
  44. 2 points
    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.
  45. 2 points
    Greetings to all, just wanted to take a quick moment to introduce myself. I have been riding for over 20 years and I figured it was finally time I got my but to school. I will be attending the 2 day school at VIR on August 8th and 9th and I could not be more excited. I have read Keith's books several times over the years and have always wanted to take it to the next level i.e. racetrack. Thanks to a friend at work who has attended multiple California Superbike Schools I finally took the plunge. I know it will be awesome. Best Regards, Catfish
  46. 2 points
    Here's some hints on these rear tires slides: LISTEN to the engine, how smooth is the throttle application when leaned over? Watch the rider on the R1s throttle hand - what does he do when the rear tire starts to slide? What control could a rider be using that could cause the rear tire to slide on the entry? What could a rider do on the corner exit that would cause the rear tire to be under much greater load than the front? I'd also ask - especially in the case of the black guy on the black bike near the beginning of the video - what is the condition of the tires, and are they adequately warmed up?
  47. 2 points
    Drag racers rebuild their engines after each run. You really think cost is preventing them from running a skinny tire if they could gain a tenth? No. I have corresponded with the author of the article you link and while he might understand physics, I'm not convinced he understands motorcycle dynamics in a practical sense. The truth lies somewhere between the two. I have yet to find the answer. But the closest reasoning I've read that the coefficient of friction rather than being a constant can vary with temperature. Large contact patch might resist temperature change hence resist changes in coefficient of friction. Additionally, coefficient of friction does not accurately describe a rolling and cornering tire that operate with some slip angle. The tire is not stationary but not sliding either. No, it is too simplistic to say contact patch doesn't matter. From a practical motorcycling sense, much of Code's teaching talks about contact patch and friction. Based on all that practical experience of thousands of riders, there is some truth to the statement. Just my opinion.
  48. 2 points
    I get the sensation of "pushing" the bike up as a countersteering input coming out of the corner. If you remain in your "hang off" position or even exaggerate it on corner exit with your upper body, you really have no recourse but to countersteer the bike back upright out of the lean. For me that movement of putting bar pressure on the outside hand ( and pulling with the inside hand) could be interpreted as "pushing" a bike up. It's not a subtle sensation. Sometimes you'll have to really "push/pull" to straighten the bike up to get ready for the next corner. Maybe you are essentially saying this...
  49. 2 points
    Think of the muscles in your back and your abs, as ratchet straps that support your torso. If you don't tighten them evenly, one will be overtightened. In most cases the lower back contracts to far leading to pain and loss of strenght.
  50. 2 points
    Do you have a copy of Twist of the Wrist II? Chapter 19, Pivot Steering, goes into specific detail about weight distribution on the seat and pegs, explains what to do, how to do it, and why, with specific explanations and examples of the effects on the bike. It's far more complete and informative than what could be typed here. Take a look at that if you can and let us know what you think, or if you have any additional questions! BTW, if you are like me and want answers as fast as possible, Twist of the Wrist II is available as an e-book now, here is a link to it on Amazon: http://www.amazon.com/Twist-Wrist-II-High-Performance-Motorcycle-ebook/dp/B00F8IN5K6/ref=sr_1_1?ie=UTF8&qid=1461194283&sr=8-1&keywords=twist+of+the+wrist+II+kindle
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