racer

For upshifting: Back off the throttle enough to eliminate any lash in the drive train. At that point where there is neither acceleration or deceleration and everything is sort of "floating". (Especially inside the transmission.) At this point there should be little or no resistance from the shift lever to shifting up. Then get back on the gas. This is all done quite quickly. The entire process is faster than shifting up with the clutch though the exact timing will vary somewhat depending on the rate of acceleration or torque and revs just prior to the shift point. In other words, if one is not accelerating very hard there is already less lash on the trans/drivetrain to start with so less backing off would be needed. It does take some experimenting and practice. Using the clutch essentially accopmlishes the same free floating lack of lash in the transmission by separating the tranny from the engine. As for downshifting without the clutch: It's sort of the same deal in needing to back off the gas and reduce lash but instead of just backing out of the throttle, one needs to incorporate a "blip" to match revs for the lower gear. It is quite a bit more difficult to learn to do smoothly in my opinion and I find it much easier to do on a two stroke road racer or dirt bike than a four stroke. (Probably because of the lighter crankshaft and flywheel rotational mass to create less drivetrain lash force in the gears to resist the shift.) I definitely recommend mastering the downshift/blip while using the clutch before attempting to learn the clutchless downshift. In any case, I don't generally use it on a four stroke motor except to impress myself or show off to a passenger in a car or truck. It just takes too much attention for me and I don't find that much is gained.

Hey ghost_r1, If you can give me all the numbers including the new and old clamp angles as well as the tire sizes and state of wear I will try to help sort what is going on for you. I'm glad you brought this up specifically because it touches on something of a pet peeve of mine. Namely the correct concepts, functions and definitions of "rake" and "trail". I feel some less than clear or complete definitions, descriptions and functions have been put forth on this website and I'd like to take this opportunity to try to clear it up for myself. I don't have time to get all into it today but please give us some more detailed info on your front end and I will get back as soon as I can. Thanks, Racer.

And... Since this time last year I've thought a lot about Cobie's comment that started me off on this whole trip. Something to the effect that Kawasaki had raised the engine on the new ZX-11 to give gravity a longer lever and enable the bike to turn in faster. I jumped on that and people started talking about mass centralization and center of roll, etc. After watching the awesome videos on this thread I find myself still less than clear about where that center of roll is. And just exactly what happens between flick and carve. Maybe I should start another thread for that. Gotta run now. BYE.

Excellently put, Racer. Thanks Woody! It's OK for a quickie first draft I guess but definitely needs some work IMO. Always room for improvement. However, we've certainly come a long way since ... the last time we were on this side of the solar system together discussing this subject. Like about 600 million miles or so...haha. I've changed a few words and added a few for now. Check it out, dude! I'll be back. Cheers, Racer

To continue, elaborate, expand and hopefully clarify... The forces involved with steering a bike feel the same to me as steering a car or any other vehicle with two or four wheels. As passengers, we're all familiar with being pushed up against the car door or against the person next to us when a driver corners at high speed. If I steer my car to the right, the car's and passenger's weight attempt to continue in a straight line and we feel "pulled" toward the outside of the corner (or to the left). This feeling of being pulled toward the outside of the corner is known as a centrifical or centrifugal effect and is sometimes called lateral g force. The car will also tilt or lean toward the outside of the corner (left). However, with four wheels and a wider wheel base, the car is a fairly stable platform and tends to track in the same direction as the initial steering input through a corner. It requires a high degree of force to completely roll a car over but it can be done and is done by many drivers everyday. A top heavy vehicle like a van will roll over even easier. If you could balance the "rolled" or "tilted" vehicle on two wheels you would lean and countersteer just like a bike. In fact a skilled stunt driver can do exactly that in a car. To say it directly, a two wheeled vehicle such as a motorcycle is an inherently unstable platform that doesn't take much force to tip or roll from vertical. Any steering input will create lateral g or angular acceleration (just like the car) causing the bike to lean, tilt or fall in the opposite direction as it doesn't have another set of wheels to hold it up (like the car). At very slow speeds, the forward momentum and, hence, the lateral g force, is small enough that a rider can compensate with his/her weight (distribution) to stabilize the bike and prevent it from tipping in the opposite direction from the initial steering input ... thereby causing or allowing the bike to continue tracking in the direction of the initial input. But make no mistake...a slow moving bike will indeed countersteer and fall the opposite direction if a rider doesn't compensate. AND...that same slow forward momentum and, hence, lack of lateral g force, might not be enough to balance against gravity and maintain a lean angle. Boom. Questions? R

Hey Tim, I got timed out at the library yesterday before I could elaborate on my last post. I would suggest that you cannot accurately analyze or fully understand a dynamic process like steering a motorcycle by referring to static pictures of rake/trail and contact patches in your mind. That said, consider the forward motion of the two wheeled vehicle. Whether one wishes to think of it as the front wheel being steered out from under the machine and the bike "falling" in due to gravity or forward momentum carrying the bike over or even a combination of gravity and forward momentum... the bike will fall to the left when you pull on the right handlebar steering the front wheel to the right. Definitely go do it. There is nothing like the real thing. Naming isn't knowing. Intellectualizing will not help you to truly "grok" the reality of countersteering... Cheers, R

Tim, You are wrong on point number two.

I find brake pads cheaper and easier to replace than clutch plates. I spoke at length on this idea many times but using the clutch becomes inefficient as well from a riding perspective and reduces a rider's control of the engine or go force.

If a bike leans over, it counter-steered to get there. If I try to turn without leaning (at very slow speeds) I find myself wobbling around trying to stay upright and balanced and feel constantly in danger of falling because the bike wants to lean over or counter-steer to a lean angle and I don't feel like the bike is going fast enough to balance or carve at lean. In my mind, the concept of non-counter-steered turning at slow speeds is a misnomer as you chase the balance point around trying to turn without leaning. So, how do you define "turning"? For all practical purposes and, in my opinion strictly speaking, it only happens byleaning, hence by countersteering. Cheers.

Hey all, I was talking to a physicist the other day who said he had intended to do his master's thesis on the physics of the bicycle and gave up because the math was just too complex. This was before modern computers and he was including the rider as a dynamic variable...duh. Rider as a dynamic variable...the nerve. ANYWAY... @ mike I don't get your point about the contact patch being flat and the cup being flat so the different radii don't apply....what? They are both flat and the analogy is pretty much perfect. The inside edge of the tire is a smaller radius circumference than the centerline. Just like the cup. Imagine gluing a non-conical tubular section between the cups to represent the upright position of the tire. The moment you lean over, you are rolling in a circle. If the paper cup thing doesn't do it for you, then why do YOU think a wheel rolls in a circle when it leans over? @ all As for counter-steering vs gravity vs precession... I believe it is the angular acceleration or lateral g that drives the "counter-steer" effect. However, the question I find most interesting at the moment is whether something more than gravity affects how fast the bike flicks over so to speak. Does a bike dropped from a static or standing still position in the paddock fall slower of faster than a bike flicked into a corner at speed? And why?

OK my brain has been consumed with magnetics, particle physics and answering the question of whether the universe is an open or closed system with regards to energy and mass conservation and how that might relate to the possibilities of energy and the relativity of magnetics and gravity frame dragging. Is there such a thing as relativistic magnetic energy frame dragging? So, it's gonna take a while to shift back into relativistic knee dragging. But...notice in the tagteam video how the bike continues to lean after the wheel has ceased turning and even straightened back out again? Gotta go. Be back tomorrow.

G'day Racer, how's it hanging? As does a single bicycle wheel, rolled at an angle. This would appear to support the paper cup theory (and is probably what inspired it). However, a motorcycle has two wheels, not one. Roll two bicycle wheels, one behind the other, both at the same angle and the same speed and each will follow the same arc, but each will be at a different position in the arc. Because of this, they will not be in line (one directly behind the other). The leading wheel will, relative to the second, be pointing more into the turn than the following wheel. It's a similar story with a motorcycle (although yes, there are differences as both motorcycle wheels are connected by the frame). Need... mince... pies... G'day to you Woodrow! It hangs, mate! It hangs! And what more can a man ask for in life? A rip snortin thunder machine? As for bikes... My thots exactly. Will a longer frame/wheelbase create more front wheel offset at a given lean angle? Or a wider turn arc for a given lean angle? Will the size of the (rear or front) wheel dictate radius of turn at a given angle? Or dictate the front offset for a given front wheel size? Will the rake/trail affect the angle of that offset? Hmmm... Oh...who cares? Mince pies. Mm-mm! Fond memories of lunch on the go between jobs in Auckland! So, are ya back to Tasi this year?

hmmm. A unicycle turns in a circle.

You can pretty much copy/paste mike isbill's answer for me. Starting with the solitude and beauty of touring right down to the obsessive/compulsive competing with myself for the sake of being the best I can possibly be. That is to say like the ancient Greek philosophy of Arete as experessed in Zen and the Art of Motorcycle Maintenance..."Excellence for the sake of excellence". And competition seems to help bring out that extra bit I never knew I had. Teaching completes the cycle.

Hey guys, One thing to keep in mind is that at a proper practice day, or club race, bikes are separated into classes to begin with. It isn't always perfectly matched, and the different classes you or your bike will run in may vary from place to place, but, it isn't like you will be riding a Ninja 250 with 600's beyond the school. The last time I raced against a bunch of SV650's they romped all over me and a grid of FZR400's. So, it's all relative guys. In any case, frankly, learning how to back off and time your corner entry relative to slower cornering riders to complete a pass is a basic racetrack skill you will need to master no matter what bike or class or group you run with. You cannot avoid it by riding against similar powered machines. There will always be slower cornering riders to pass. Especially with a faster hopped up motor in your class to ruin your day and buzz back by you down a straight for free. And those are some of my proudest wins. Beating a slow rider on a faster bike. Yeah baby! That's SKILL! Slower cornering riders. Get used to it and learn how to handle it. It's a fact of life on track. Cheers, Racer

Hey sanfret, Well, you sure LOOK fast...lol. Regardless, that is an AWESOME photo! Fontana looks like a cool track. Racer

Hey James, I agree that progress requires work. Speaking from experience, there is nothing more regrettable than unrealized potential or undeveloped talent. Racer

Hey James, That is a wise conclusion. I do recommend upgrading the suspension before track day. I think you saw the post re: sources like Muzzy. Talk to the guy doing 1:40 @ Willow for more hints. Your thoughts are the ones that count! Good luck! Racer

gixergeezer, I can't speak to what percentage of superbike school students are "your age" in the physical sense. However, in spirit, I'd say everyone is the "desire to ride better" age. If you are buzzing about on a Fireblade without falling down or forgetting to stop at stop signs on the street, I would urge you to go for it. You do not have to worry about being too slow or getting in the way. The school is a very controlled environment and there are rules against aggressive passing. You should not worry about getting spooked or run off by faster riders. The standard schools are about learning. Not racing. If you want to do it, I say do it. Time marches on. Racer

Hey James, I agree with you that a 250 Ninja is a good place to begin. It might be a bit too small for larger folks, but, for cornering skill, it is an excellent trainer. CSS used to offer the 250 Ninja as a school bike option. In fact, I rode a school 250 Ninja at Mid-Ohio and Watkins Glen myself. Racer

Hey Alan, Four seconds? Wow! That's awesome! I agree! Breathing is a GOOD thing! Sounds like somebody enjoyed themselves. Glad to hear it! I'm jealous! Gotta run. Cheers, Bill

Tim, I agree. About the sketch. I think I also know what it is you mean with your words, and I think I might even agree at this point, but, I'm just not quite clear. We may very well be thinking the same thing and coming at it from opposite directions. Anyway, as soon as I have a bit of time, I will get back ot offering a direct opinion rather than picking nits with yours. Cheers, Racer

I guess it was these two sentences that confused me the most.

Hi Tim, I don't think that a line drawn from the contact patch to the CG will pass below the swingarm pivot. If I shift the swingarm forward such that the pivot is located forward of the CG which is now located above the center of the swingarm, the swingarm will still rotate around the axle under acceleration. The bike will still rise. Forward acceleration is resisted by the mass of the bike, aerodynamic drag, and friction in the wheel bearings and drivetrain. It is not resisted by a horizontal force at the contact patch. Thanks, Racer

Hey Tim, The downward force of the mass of the bike caused by gravity is balanced by the ground pushing back up. Inertia or forward momentum of the whole bike is essentially irrelevant to the effects of acceleration on the swingarm. We can have accelerataion from a dead stop or from a hundred miles an hour. In either case it is the acceleration that is applying force to the swingarm. The traction force at the contact patch pushes back against the tire with exactly the same force as the tire pushes against the road surface from acceleration. It is balanced. It is NOT an external horizontal force pushing the motorcycle forward. There is NO external horizontal force pushing on the back of the wheel or the axle. If we backed the bike up against a wall, that would be an external horizontal force being applied to the back of the wheel or axle. But that isn't what is happening. The only unbalanced force being applied to the wheel is rotational acceleration. If we prevent the rear wheel from rotating, it will rotate the swingarm up. If we allow the rear wheel to rotate, the wheel will roll forward, and acceleration will rotate the swingarm up. This is true no matter what angle the swingarm is to the frame. Hence the acceleration force applied to the frame of the bike is not horizontal. The acceleration force applied to the frame of the bike is at an upward angle. Hence the bike rises under acceleration thereby shortening the wheel base. Any chain pull offset below the angle of the swingarm will increase this effect. Cheers, Racer