racer

Could you please explain that in plain english for us blind and uneducated ignorants? Or preferably post some mathematical equations and freebody diagrams to support this premise that just "appears" for you. How much centripetal acceleration would be "enough"? How do you define "enough"? How much angular acceleration about the CG (fore/aft) do you consider to be significant? Do you still believe that angular acceleration about the CG (fore/aft) is the only force that could increase "reaction" at your outside peg? I believe these are fair and appropriate questions that go straight to the heart of your premise... and your question.

Meat, Apparently there is some issue with the server here as several posts were not up when I replied this morning before leaving for work and have since appeared (for me) above where I replied. So, I did not see where you stated your explanation of "it wouldn't appear"... which is total BS. Your entire premise in the post to which I referred remains unfounded and unsupported by any physics theory much less proof. As do your accusations. I have no idea how I have attacked you, or how you are twisting or perceiving my words, or imputing my intentions in your mind to believe I have. However, your attack on me, my character, my intelligence and integrity is pretty straightforward. I can see how you might be feeling a bit sensitive after some other replies to you in another thread where you blatantly and rudely attacked the school, but, please don't take it out on me. That said, IMO, your energy has been particularly negative and disruptive in more than one thread. If you do intend to post more, I for one would ask that you please try to be a bit less nasty, self-centered, egotistical and narcissistic. I would also suggest that you leave the victim card in your pocket. The 'poor me' game doesn't carry much weight around here or anywhere else around the race track. And it certainly doesn't make up for a lack of evidence, explanation or intelligent discourse. Nor do insults and characterizations constitute a valid argument. That is not meant to be an attack. It is intended to be a polite request and sincere advice. Regards, racer PS - For what it's worth, my engineering degree is electrical. Not mechanical. But I eagerly await evidence to support your accusations regarding my understanding of physics or perception of engineering. Please point or link us to the relevant posts or quotes. I am always happy to be wrong. Being wrong is the beginning of all learning.

Yes, completely. Exactly. Precisely. Thank you for putting into plain english what I couldn't.

When you hang off, the CoG is off-set from the mid-plane of the bike. As I understand it, the overall downward force follows the CoG. Hence, why the bike follows the same line when hanging-off/standing up more. So, the down force does not change. It remains where it was. With the bike more upright this should give the angle of force from your body an "overturning moment" around the z-axis (longitudinal). In any case, one way to get off the inside peg is to lock onto the tank with your outer leg. Yes, when you hang off, it moves the CG to the inside. And yes the resultant force (including moments) all act through the CG of a body (body here means combined mass). No, the downforce can not change in a straight line (line meaning vector) unless you eat a lot of Big Mac's on the way down the straight. The only way the resultant downforce (down to the bike, not to the earth) can change is by changing the direction of the bike. The bike's lean angle is at equilibrium once you make your initial flick and hold it. So, the bike isn't rotating about the longitudinal axis. You don't need to do anything to keep the bike turning, once it is turned. And, the farther the riders body is to the inside, the less weight is on the outside peg. Yes, as I stated putting your knee into the tank will only lessen the force on the outside peg. I need to know how you ADD force to the outside peg. You either did not understand what I meant or apparently you didn't hear me. You seem to be repeating yourself while ignoring my replies and questions of clarification that you have edited from the posts you quote here. That said, assuming the rider does not move from whatever position they are in, there are two ways I can think of to add more force to the outside peg. One is to ride faster, the other is to lift the bike to a lesser lean angle. If you want to know what these riders mean, I would start from a position that does not assume what they are saying is impossible. I would try looking for the conditions that do allow what they are saying. Unless you think they are all insane or something?

I've tried to offer some insight from my point of view, but, you seem to be stuck in a box of your own making. And trying to drag others in with you while not answering or even considering the questions or ideas I've pointed you toward. As I said up front in my original reply to avih, (like you) I've heard other people talk about favoring one footpeg or another. I've never done it. I have no experience with it. I really have no interest in it. Not sure why you are apparently so obsessed with it. Or obsessed with proving it is impossible. But, if you want to know what somebody else meant, I suggest you ask them. At the risk of repeating myself, again, I think it has more to do with the choices and actions riders make with their flexible bodies and muscles, as opposed to moments or combined CoG or whatever else one sees in a static snapshot analysis of a freebody diagram. Perhaps it has less to do with conditions and more to do with what the rider is doing. The rider is not a static free body diagram. And neither is the bike. There is more than one lean angle, eh? That's my best guess. Good luck with your quest.

Hey Jeff, Glad to have you aboard! Look forward to hearing more about your time at the school and regular updates on how your riding is progressing. Regards, racer

Hi duc766, I'm really sorry to hear about your crash(es). I'm glad to hear you are going to be OK and hope that you heal well. And I hope you have good insurance. You should contact the US Marshall's to find out what happened. You can contact them here. If you were transported, something would have been recorded about what happened. At least they could put you in touch with whomever was working Turn 1 and you could talk to them to find out exactly what happened. If you have any difficulty, let me know and I will help you. It's important to find out. Even if it wasn't your fault, simply knowing how the incident developed can help you to avoid similar situations in the future. Loudon Turn One can be a challenge to find the groove at first, eh?. You have all that room to sweep in hard off the front straight, but, then you have that nasty transition from the banking to the infield. You said you were going in deep to snap it in. Did you mean before or after you came off the banking? I take the transition at a shallow angle and then bend it off. Anyway, did someone else travel to the track with you? How did you get home from NH?

Did you say that you had read A twist of the Wrist? If you haven't at least read the first book, you really need to get it. All of this is covered in the books. How to choose a good line, how to pick reference points, etc, etc. I know I'm beating a dead horse, but, I can't emphasize it enough. What we discuss here barely scratches the surface. There is so much information in Keith's books and they are very, very easy to read. They are written so anyone can understand them and the information is absolutely critical. All the fundamentals that form the foundation the more advanced stuff is built on. Help me out here, dude. Meet me half-way. Throw me a bone. Or at least a 12mm combination wrench....

When you hang off, the CoG is off-set from the mid-plane of the bike. As I understand it, the overall downward force follows the CoG. Hence, why the bike follows the same line when hanging-off/standing up more. So, the down force does not change. It remains where it was. With the bike more upright this should give the angle of force from your body an "overturning moment" around the z-axis (longitudinal). In any case, one way to get off the inside peg is to lock onto the tank with your outer leg.

The outside foot should be up on the toe. Then your knee jammed into the tank. This is the gist of the "calf raise" the school suggests you "lock on" with. Applying Stomp Grip traction pads to your tank should help with that. But even if your knee isn't jammed into the upper lip, I think you should still be able to get some weight up there. http://www.stompdesign.com/stompgrip/home.asp Edit: I looked at your pictures again and I don't know if you really need to hang off more. The school says you should be lower. I don't know if that will help get your knee down, but, it does look like you could stick your knee out further. What year is your CBR? How wide is the tank at the seat?

I don't know what notion or "perceived extra agility" you are refering to, but, I don't quite follow what you mean wrt steering less mass or less effective action. Your body is still connected to the machine and moves with it, no? In a nutshell, the footpegs are closer to the bike's center of gravity and the z-axis (roll), so, there should be less resistance to steering input. In any case, the footpegs make a more effective or efficient point from which to intitiate steering input. Have you read the Twist of the Wrist books?

It's a matter of angular acceleration and centripetal force. Ride faster. It wouldn't appear that you could generate enough centripetal acceleration of the bike and rider about the turning radius to create any significant angular acceleration about the CG (fore/aft axis) to be able to alter your reaction at your outside peg. The overall force in a turn should be very close to the mid-plane of the bike. So the centripetal acceleration (or force if you like) is offsetting the acceleration of gravity...and hence you have a lean angle that is at equilibrium. "It wouldn't appear..."? What does that mean? The fulcrum of the moment arm (if you will) that is the motorcycle is effectively defined by the contact patch(es) of the tires because the motorcycle is essentially a rigid body with no choice in the matter. The limit of that relationship is defined by available traction. What defines your moment arm? Are you a rigid body? Do you have a choice? For the record, my point was that I don't attempt to push on one peg or actively "weight" one peg more than another. That statement speaks to my efforts. Whether that means my "weight" (if you prefer) is perfectly balanced between the two pegs is another matter I suppose.

It's a matter of angular acceleration and centripetal force. Ride faster.

My apologies for such an unfortunate choice of words. I did not mean to imply, scientifically, that the rider/bike combined CoG is actually altered. I was pressed for time and uncertain how to express the concept precisely or concisely, hence, I attempted to qualify my remark with what might be considered colloquial phrasing. By using the word "essentially", I meant "from a practical standpoint", ie. the effect it has on how the bike handles. Perhaps I should have used the word "effectively". Hindsight is 20/20. That said, however, it is more than a mere matter of legs acting as dampers. While this does occur, especially in motocross or even over rough pavement, and having your weight attached higher does create a longer moment arm for lateral torque/oscillation, this is about more than simply limiting or attenuating amplification of unwanted movements. The salient point is that where you attach yourself to the bike does, in fact, have a significant effect on how the bike reacts to control inputs. Hence, from a practical standpoint, and with a shorter moment arm, the bike reacts as if the mass were "more centralized", if you prefer, because, in fact, from the machine's point of view, it is.

FWIW, I didn't start to ride that way, on the pegs, until I switched to a GP bike. And it was then that I really took my riding to a new level. Sort of a 'me taking the bike for a ride' vs. 'the bike taking me for a ride' kind of thing.* It does take a good bit of leg strength, but, it essentially lowers the point where you attach yourself closer to the bike's center of gravity and makes the bike much easier to control, as opposed to having your weight up so high on the seat. I try to keep my weight evenly distributed between both pegs. Like I'm standing on the pegs crouching down low. I'm told that weighting the inside peg can help intiate a slide. Or that weighting the outsde peg can help control a slide. I only started experimenting with sliding the rear on purpose in the last year before I quit racing, so, I can't offer too much personal insight into that. However, I did find that being on the pegs gave me better control of many things. * When I drive a car, I may be strenuously working the pedals, steering wheel and gearshifter; but, I am basically strapped into a chair operating the controls of a big box with wheels. I am essentially sitting in a seat and 'along for the ride'. Riding a motorcycle is nothing like that for me. It's more like me doing gymnastics with wheels attached to my hands and feet... if that makes any sense to you. There's really no "sitting" involved.

I (try to) keep my weight in my feet, avih. (Evenly distributed between them.) The only time I'm (purposely) sitting on the seat is to rest down the straightaways.

It seemed to work for Luke.

The amount you are hanging off in some of the pic's is probably perfect for a 125 or 250 or a smaller bike. The one cheek sneak is probably even good for a 600. And you don't look much different from some pro-racers. But, according to the school's technique, your head should be down next to the windscreen. I know it must be more difficult for a taller person. I'm only about 1.70 so it's probably different for me. One of the coaches with more experience could probably say better for a taller rider. Also, getting your upper body further over off the bike might make it easier to get it down lower. Otherwise, just lean the bike over further and stick your knee out more... Good luck!

Perhaps I've been using the Han Solo riding plan - just some simple tricks and nonsense. Maybe you should try riding with the blast shield on your helmet down, erm... a dark tinted shield on your helmet so you can't see anything?

Hello again, avih. Welcome back. Your general body position is not too bad, I think you just need to get your head and shoulders down and maybe get a wee bit further off the bike. That, and stick your knee out further. Look at the guy behind you to the right in picture four. You can see half his body exactly behind yours in the shot perfectly. Everything is parallel between you except for your lower leg and knee. Look at the difference in angle between his lower leg and yours. A general rule of thumb says, the bigger the bike, the more you need to hang off. Not just to reach the ground, but, also to affect the center of gravity. In general, I think you could hang off a little more. Most importantly, I think you are a little too upright. Try to get your upper torso, shoulders and head lower if you can. You want your head down lower and a bit more over off to the side, "kissing the mirror" if it were there. And the same with your bum, keeping your body in line parallel with the bike. How far back in the seat are you? I know you are tall, but, can you slide back any further? It might help you stretch out a bit and get your shoulders down. What are you doing with your outside leg? Are you locked on? So... 1. Slide back a bit if you can. 2. Get your head and upper torso down lower. 3. Then mabe get a little more off the bike if you can remembering to stay parallel. 4. Stick your knee out more. Hope that helps. racer

Hi Tweek, To the point: as has been previously stated... although there are many possible lines through any corner that could be called "good", foregoing any competitive considerations, there is one "best" line for a given machine and corner. One that allows the best control with the least effort which by default leads to the fastest lap. Perhaps it is not far off of your so called "mechanical" line. Regardless, I don't think this is your real issue. As you state in your blog post, you are having difficulty consistently sticking to the same line. Well, the bottom line is that until you can reliably and consistently achieve a specific particular line that you have planned to use, the rest is so much irrelevancy. By default, you will always be, by definition, out of control, ie. rather than you choosing your lines, your lines are choosing you. Considering the difficulty you are having, it is understandable that one might wish to find fault with the goal. Why have a plan? It is so much more fun to simply see what tomorrow brings and isn't that the ultimate challenge? To go through life or lap able to dance with any situation that may arise unexpectedly? Isn't that the real skill? To live the Neverending state of crisis management that allows or enables one to ignore the ugly truth one doesn't want to confront....? (It is a kind of rush isn't it? The adrenalin, the surprise. It can be rather addictive actually.) I mean who can really predict the future anyway? Is there really any such thing as control? Isn't all control merely an illusion when there could be an earthquake or a pothole or an act of God? Is there really any such thing as freewill at all? Even in such a "controlled" environment a racetrack, a corner worker could spaz and jump out in front of you... I think that if you are honest with yourself, and according to your blog post it seems you are, then you must realize that until you can actually ride a line that you choose, falling back on some beat zen philosophical BS is at best avoiding the truth and more likely a cop-out. Only when you are able to ride a line of your choosing at will, to put the bike anywhere you want as if you were one with the machine and closer to thinking the bike around the track as opposed to riding the bike around the track does the endless choice of lines become a reality for you. Until then, it is not an infinity of choices, it is merely an infinity of possible random outcomes. You might as well hold a lottery. How much skill does it take to guess a winning number? About as much skill as it takes to guess where you will be ten seconds down the track. You know, some people really do live their lives like that. I wonder if ones riding style or approach to the track might reflect ones approach to life in general? How much could you tell about a person by watching them ride, I wonder? Baa... The trick is to slow down. Choose your reference points ahead of time. Make a plan and stick to it. Only go as fast as you are able to see and use your reference points to guide you. Once you can master the process going slow, adding more speed is easy. And once you understand how to choose the best line, then you will be able to ride any line you choose. Keep working at it. You'll get it. r

Thanks for sharing that, Tim. I've always wondered what a 2-day camp was about. Very informative and entertaining.

I always make sure to get a ground floor motel room so as to utilize the free climate controlled pit with wall to wall, showers, built in beds, HBO, microwave, private access and swimming pool. All my bikes live where they belong... in the living room. Of course, my bikes are immaculate works of art that are better cared for than most people's children. Never had a problem with bikes "wreaking" or smelling up the motel room with fuel vapors. I suppose if you were transporting the bike in 31 degree weather and then brought it inside without equalizing the tank pressure...

"Have a wonderful day, in a one way world..." ~ PG

Without a speedo, it's really impossible to figure unless you know what the final gearing is (sprockets) and what the primary drive ratio and 4th gear ratio is inside the motor. If I recall correctly, running original street gearing, 4th gear on a typical middle weight sportbike is going to be from around 90 mph at the beginning of the powerband (say 9K rpm) to maybe 120 mph near redline. But I'm really guessing here. It's been a long time since I owned a 600 or figured speed in gears for one.