Woody

Oh yes, and what he said... get yourself booked on a level 1... :-)

Sounds like this could be a number of things... But... it could be a simple matter of gripping the bars too tightly and so not giving the bike a chance to settle into the turn. It's quite common for a rider to unconsciously stiffen up, tightening their grip and keeping the bars turned, effectively steering the bike into the ground (also manifests as running wide on the exit). Next time you go out, to reduce distractions, slow everything right down and then try forcing yourself to relax your upper body (your grip should be fairly relaxed and you shouldn't be using the bars as a support). Try to think about what you are doing, your position on the bike, your grip on the bars and how this changes when you start cornering. My hunch would be that you're stiffening up when you're heading through tight corners and this is giving you the feeling that you're falling. Your worry is only creating a vicious circle where you unconsciously tighten your grip even more, which only makes matters worse. Sure, check your suspension also (this could well be worn and there's certainly nothing to be lost by giving it an overhaul), but generally, failing any serious mechanical problems (which would pretty much show themselves in a straight line/ gentle corner as much as the tighter stuff), the main cause of ill handling bikes can be traced back to what the rider is doing.

The natural instinct is to turn the bike, or else we'll die(!). The brain sees a corner and thinks "got to turn, got to turn, got to turn" and then what happens? We turn and apex early. Understanding this is crucial to imroving your cornering for both track and road. With track riding it is much easier to practice different approaches to a corner, as you know what is going to be around the next corner and, riding in circles allows you to try different approaches for the same corner easily. Road riding is a different beast, as it is often the case that you don't know what is going to happen and so forming a plan of approach is much more difficult. Because of this, your brain tends to throw a wobbly and do what it thinks is safest, head to the inside of the corner as soon as possible. In effect, you need to retrain your brain and I found that the best way to do this is by thinking about sighting. I know that my eyes are the most important part of my skill set and I also know that good vision is paramount so that I can form a plan for each corner. Knowing this, I find that my riding adjusts automatically for road or track riding. For example, whilst road riding I will at times lean away from the bike to give myself a better view rather than to improve my ground clearance, this may even require me leaning 'the wrong way', depending on the conditions (you should never be so close to the limit so as you can't adjust your body position on the road), whilst on the track, after a few laps I will have a fair idea of where the track goes, so I can concentrate more on improving my corner speed (I'm still slow mind you, but then I am old and greying!) and so will spend less attention on getting a great view of the track and more on getting a better weight distribution on the bike. I'm still looking ahead, mind you, but just so I can see where my turn points are. Woody

Also try doing as Cobie suggests and reduce the play on your throttle cable, it helps enormously.

Got to agree with Cobie and kwh. Laaate apex for street riding. Not necessarily the fastest way through the corner, but much much safer and you'll find yourself making fewer mistakes as a result of having good sighting. There are so many unknowns with street riding that the approach must be different to track riding if you are to stay alive.

I would have said that as a general rule of thumb, the less drive you have, the closer you should be to the 'classic' line (nice wide arc). If you have a big powerful engine (as a MotoGP bike would have), I expect that you'd be wanting to use as much of that power as you can (otherwise what's the point in having it), so you'd be looking to pick the bike up early so you can get as much drive as you can, as early as you can. The basic theory would be that a powerful engine can make up any shortfall in mid corner speed by going faster at the corner exit (which also leads to greater speeds on the straight bits)... I expect that the rider's weight distribution will also have a greater effect on corner speed for smaller bikes. To corner faster, the rider positions their weight more to the inside of the corner. The lighter the bike, I expect the greater effect this will have, allowing you to pick the bike up further than you would a heavier bike (or, allowing you to go faster for a given lean of the bike). Also, 125 GP bikes are a bit slimmer than MotoGP bikes, so you probably gain a little extra clearance there too. What is it that ultimately limits corner speed? Lean angle! Don't mind me, I'm just thinking out loud...

We're heading toward some very rough waters here. Lean is a necessary byproduct of cornering forces. It is what stops the bike from flipping over whilst cornering. It is what gives the bike balance through a corner. The amount of lean is relative to the speed of the bike and the rate of turn. Lean more and you'll either take a tighter line or you need to go faster to retain the same rate of turn. The front wheel points into the turn. The amount it points into the turn is just the right amount to achieve the right arc for the given lean angle and speed (we set the arc through steering input and the lean follows). Turn the front wheel more or less and the bike's amount of lean changes. (Change your speed, by the way, and you change the arc.) Without cornering forces, the bike needs no lean and to generate cornering forces, the front wheel needs traction. What sort of traction would be present if the bike was at 90 degrees from upright? This will decide the state of the front wheel. The only scenarios I can think of where traction would be present are: 1. A banked corner 2. A wall of death (which is effectively an extreme banked corner) For 1. the bike would be cornering just as normal, with the front wheel pointing into the corner. For 2. the front wheel would be straight. For a flat turn, the bike would be on its side, no traction would be presented to the tyre and the direction of the front wheel is immaterial.

Whoa, that set the old nogging spinning. For a given speed, the more a bike leans, the more the front wheel points into the turn. Also, the bike lean should be understood in relation to the road. If the road is already banked, the natural line for a bike that is 'upright' (90 degrees in relation to the road) is to follow the banking and at this point it is safe to say that the bike is not 'turning'. To put it another way, if a turn is banked you need less lean to get around it than if the turn was flat. Your example of the 'wall of death' is a perfect example of taking this to the extreme. A bike going straight, yet also changing direction.

Excellently put, Racer.

I can't help but feel that the precession theory is fundamentally flawed as it is only considering the effect for one wheel, the front. When you apply the precession theory to the front wheel only then it appears sound, but this is only part of the story as bicycles and motorcycles also have a rear wheel that is connected to the front via the frame and is fixed by the swing arm (so that it is unable to twist). When the front wheel is turned, due to gyroscopic precession, the wheel will try to lean. I think we all agree that this is right, nobody has disputed this. This 'lean' will also be transmitted via the frame to the rear wheel, which (applying the very same theory) will now try to twist. However, the wheel will be unable to twist because of the swing arm. Because it will be unable to twist, the rear wheel will resist the precession effect of the front and will try to remain upright. In short, the rear wheel, being fixed by the swing arm, will resist the lean induced by the front. There will be some flex in the frame and I am sure that the bike turning will also negate the resistance a little, but I don't feel that these will be significant enough for precession to be considered anything other than having only a minor effect on the steering. Happy New Year, by the way.

I confess to using the front only. I've tried using the rear, but so far have found that all this does is use up too much of that precious $10 for no apparent gain. Perhaps it is something that I should continue with, but then I am perfectly happy as I am (I don't feel as though there is any real benefit to using the rear). Even low speed. I've tried it and still do, but again I really haven't seen any benefit in using it, or reason why I should.

I wouldn't know where to begin to produce a video or animation, but think that these would be a great idea. Instead, I'll try to summarise what I've said previously in as simple a way as I can. Steering is simple. A motorcycle/ bicycle will try to go to wherever the front wheel is pointing. Period. (Remove the words 'try to' if you want to be really simple.) In longer words, point the front wheel to the left and the bike will try to go left, point the front wheel to the right and the bike will try to go right. When we start to learn how to ride a bike, we learn very quickly that to turn a bike at any kind of reasonable speed we also need to lean it. We find this out through trial and error and it becomes instinctive (we don't need to think about it) very quickly. Our brains are clever enough to deal with all of this without our making any conscious effort to work out any complicated physics. 'Countersteering' is the method we use to lean the bike. This is the instinctive bit (the bit we don't think about ... until we go to the cornering school or read Keith's books). Here we need a little understanding of physics (inertia). Whilst moving in a straight line, when we turn the handlebars, the front wheel tries to go in that direction. However the rest of the bike doesn't know this and wants to continue in a straight line. Because the front wheel is going in one direction and the rest of the bike is going straight on, the bike leans over. Hold a broom handle upright against the floor and kick the bottom. It's effectively the same thing. A video would be great here. As the bike leans, the weight of the bike, combined with the steering geometry, forces the front wheel to point into the turn. I struggle here to put this into words simply enough (as I probably don't understand the physics well enough). I have mentioned some practical experiments earlier. These may or may not be very good or relevant, but I'll repeat them anyway. Whilst moving slowly forwards, turn the handlebars and note what happens. The bike will try to go in that direction. Do this at any speed and the same happens. Take a really tight turn at low speed (a U turn is perfect). You will be travelling very slowly, so any gyroscopic forces should be minimal. Note what happens. First you need to lean the bike and you do this by turning the bars away from the turn. Next you'll find that the bars will turn into the corner (you may even need to catch them to stop them from turning too far). Hold a bicycle by its seat and lean it over. Note what happens to the front wheel. It turns to the direction in which the bike is leaning, or into the turn. Maybe the above aren't the best descriptions and I've no doubt the professor that Ulrich directed us to could do a better job. That was excellent reading. Please guys, flame me all you like. I think I'm right, but don't we all Hey Racer, no no plans to head to Tassie again any time soon. Just returned from a trip down the Great Ocean Road though, caravans and all (NZ next Christmas, DEFINITELY!)

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...

I would say that you are mistaken. Whatever force you are applying to the bars, the front wheel must be pointing into the corner for the bike to make it around the turn. The same applies with the 'paper cup' theory. The front 'cup' needs to be pointing into the turn to make it around the corner. If we fixed both wheels, so that you couldn't turn the handlebars and both wheels were held firmly in line, if you lean the bike, my belief is that it would continue in a straight line and just fall over. Regarding the precession theory. How many times have we seen motorcycles exiting corners with the front wheel in the air all crossed up? If precession is the force making the bike lean, turning the wheel this far would surely try to throw the bike on its' side. My guess is that we need to remember that there are two wheels on a motorcycle and that the rear wheel, being held firm, will resist what we are doing with the front. I have no doubt that gyroscopic precession and paper cups have an effect on steering, but I think this is merely complex 'fine tuning' of what is a fairly basic principle, that the direction in which the front wheel points is the direction in which the motorcycle goes.

It's funny how the subject of how a motorcycle steers keeps going on. It's a neverending circle. I have a theory that is much simpler. The lean is a necessary byproduct of cornering, which is required to counteract the forces pulling the bike to the outside of the corner. Without leaning the bike, it would tip over. Turn left, the bike tips over right. To put it another way, if you continued to pull the bars to the left, the bike would eventually fall over without turning to the right. Once leant, you need to release the pressure on the bars in order to allow the bike to turn. The bike actually goes around the corner because the front wheel is pointing toward the inside of the corner. I don't see it any other way. So, to initiate the turn the bike must first be leant over. Turn the bars to the right and the bike starts to turn right, this tips the bike onto it's left hand side. Once the pressure is released on the bars the steering geometry pulls the front wheel back around so that it is pointing into the corner and the bike starts to turn left. The amount of lean is directly related to the speed of the bike and how tight the corner is. Slow down and the bike will take a tighter line for a given angle of lean. I have three practical examples. 1. Take a turn at a relatively steady speed and roll off the throttle. What happens? The bike takes a tighter line. You need to pick the bike more upright to retain the same arc. (The opposite is also true, speed up and the bike takes a wider arc. You need to lean the bike over further to retain the same rate of turn.) 2. Hold a bicycle by the seat and lean it over to the left. What happens? The front wheel turns to the left. The steering geometry forces this effect. 3. Do a 'U' Turn. This is a very low speed manouver, btu due to the tightness of the corner, you still need to lean the bike. What happens to the bike and steering? You need to lean the bike, albeit only slightly, but which way is the front wheel pointing? To the inside of the corner. I have no doubt that gyroscopic forces have some effect, but I see this as very minor and if anything this acts to prevent the bike from cornering rather than assist. Just some thoughts for the pot. Not sure whether I have explained myself very well... Have a great, safe Christmas folks Woody

... or we could just dip our hands in our tight little pockets and pay the man to tell us. Later in the year (when the arctic Melbourne weather finally warms up) I'm planning on taking levels 2 & 3 over a weekend at PI. I'm sure Monsieur Brouggy can sort out my little demons Some interesting trains of thought though guys.

I'll bring me trike.

I now have an image of a crazy geezer sat on a swivel chair, grinning inanely and holding a spinning bicycle wheel... Later mate, much (lunch?) to digest...

Agree. Didn't we cover this in the steering input thread...? No, it would make the bike turn. Why? Because the bike is leaning and in balance. To counter steer the other way, you need to unbalance the bike by turning the wheel a little further. The reason a bike turns is because when you turn the bars you unsettle the bike (the front wheel heads off in one direction, whilst momentum tries to keep the bike going forward), the bike tips over and when you release pressure on the bars, the steering geometry forces the front wheel to point into the corner. The gyroscopic forces are minimal. Steering geometry keeps the bike upright. However, the bike is still being pulled toward the outside of the corner, and this force acts around the centre of mass of the bike and rider combined, which tries to stand the bike upright. This is balanced by just the right amount of lean angle for a given speed and desired rate of turn (line). Speed up and the force trying to stand the bike upright becomes greater and to keep the same line you need to counteract this by leaning more (or the bike will stand up and you will be forced to take a wider line). This why a slow bike can turn tighter than a fast bike. A fast bike simply cannot lean far enough to counteract the force pulling it toward the outside of the corner, and this ultimately limits the speed with which the bike can take the corner (and is also why you can take a corner faster on a featherweight 250 than you can on your heavyweight R1). If however, you move the centre of mass toward the inside of the corner (by sitting off the bike), you can take a tighter line for the same lean angle, or to put it another way, you can use less lean angle to keep the bike following the same line. Of this, we agree, wholeheartedly! It would fall over as soon as you set off. You'd never reach a high enough speed as the steering wouldn't be able to self-adjust to keep the bike upright. Even if you could somehow get the thing rolling along in a straight line, as soon as you unsettled it in any way, it would fall over. Gravity would see to that. No, it wouldn't turn. ... but if you try it, I'll pay to watch. Racer, I like these discussions. You're a crazy guy, but you're alright.

Ah yes, but doesn't the torque act both ways? Which is why the bike is balanced whilst cornering (why it neither stands up nor falls over). I would still say that the height (by height, I mean a vertical line through the bike in the same axis as the wheels) of the combined centre of gravity doesn't affect the lean angle of the bike (personally I would only ever consider the combined c of g, as bike and rider are acting as one unit, but that's me... ). Wherever the c of g lies in this axis, the bike will require the same amount of lean to get around the corner. Sitting to the side however, is a different matter as the c of g is now off-line and needs bringing back to this balance point to follow the same line through the corner. Momentum is a different issue, that only really applies during changes of direction. Still important, but I'm happy to feel this rather than trying to work it out. You're right, it's easy to try and overcalculate what is going on, instead of just enjoying the ride.

One steering input is just that, one steering input (well, it's actually two, one to enter the corner and one to exit). When you push on the bar to turn the bike, the front wheel points toward the outside of the corner and two things happen: 1/ the front wheel tries to move toward the outside of the corner, and 2/ the spinning wheel acts like a gyroscope and through some complicated physics, tries to turn through the third axis (lean). Both of these effects cause the bike to lean into the corner (the effect of the first is far more potent than the second). With the bike leant over, when you release the pressure on the bars the front wheel then turns the other way and points into the corner, following the arc of the turn. This happens naturally and is caused by the steering geometry of the bike (ever leant a bicycle whilst holding onto the seat? Same thing happens, the front wheel points into the corner). So yes, in order to steer through the corner, you must release pressure on the bars otherwise you'd keep leaning and eventually fall over. Once you have turned the bike (leant it over) the line that the bike takes through the corner is also affected by the throttle (the speed of the bike). Keep the speed constant (throttle on slightly, giving the 60/40 weight distribution that Keith talks about in his books) and the bike tracks a constant radius. Wind on the throttle a little more and you will need more lean to keep turning at the same rate (there are exceptions of course, but I'm not talking about body position or rear wheel steering just yet ). It is important to note that you should be looking to keep the bike at maximum lean for the shortest amount of time possible, after which time you will be exiting the corner. A basic plan should be something like this: 1/ set your entry speed 2/ apply a steering input to turn (lean) the bike 3/ once the bike is leant, get on the throttle to stabilise the bike and keep the line constant 4/ when you start to exit, apply another steering input to start picking the bike up and apply more throttle as the bike starts to stand up. The transition should be smooth and generally everything flows from one to the other very quickly. Think that makes sense, but I'm sure someone will say if it doesn't...

Well, g'day there If, whilst riding in a straight line you push yourself off to the side of the bike (not down, just to the side), what happens? The bike leans in the opposite direction. You need a little lean angle just to keep heading straight. To get the bike upright again you need to start turning. Finally understanding this, somewhat fundamental idea has changed the whole way that I now tackle my cornering. I guess it also goes some way to explaining how relatively unimportant it is to get your knee down. Really, you should be trying to keep the ruddy things off the ground if you can at all help it. I remember, when I was starting out, trying to get my knee down (as you do). I'd race up to a corner, push myself off the bike as far as I could, shove my knee out and tip the bike in at the very last second. I'd be taking corners faster than I ever had before, but the bloody thing would never touch. Of course in my stupid invincible adolescent way (as we all are when teenagers), I didn't know it at the time but what I was doing, quite by accident, was pretty much the best thing I could do NOT to get my knee down. By pushing myself away from the bike and turning as late as I could, I was drastically reducing the required lean angle to get around the corner. If only I knew then what I know now, eh... Ain't riding the best? I love the way you're always striving for improvements and to make yourself that little bit better/ quicker/ safer. I love it that riding is so involving, how the rider can change the way the bike acts just by moving their body around or changing their position by the tiniest amount. Brilliant! (Flipping cold though at the moment!)

Here's an interesting thought. Whilst cornering, the primary reason for leaning off the bike is to enable you to keep the bike more upright (reduce your lean angle). The common perception is that what you are doing is lowering the centre of gravity (lower c of g equals less lean angle), but watching some of the new GP stars I started thinking that this perception is misguided. What you are really doing is moving your centre of gravity toward the inside of the corner, thus allowing the bike to stand up a little more. Watching Dani Pedrosa and Casey Stoner exit corners really started me thinking about this. I pick these two, as their riding styles are far more pronounced than many of the other riders. They appear to almost ride the bikes side saddle they are hanging so far off, with the bikes virtually upright as they exit the corner. The more I think about it, the more convinced I am that this is the case and the more daft I feel for even contemplating the false view that you are lowering the c of g. Common sense alone rules this out. Apologies if anybody else has brought this up previously (I haven't done a search), but I was just sitting around not doing anything in particular when I had one of those "of course, that's what is happening" moments... as you do.

Everybody is different I guess, and what works for one person might not work for another for a number of reasons. I played with this when last at the track to find what worked best for me. In the end I found the most comfortable and smoothest method (for me!) was to drag myself around the tank using the inside of my thigh against the bike. As I passed over the bike I'd then use the other thigh to secure myself into position. This was the only method I found that avoided me pulling on the bars and upsetting the steering, but it did result in sore thighs by the end of the session (and it gave the upper body a fair workout, too). Of course, I don't sit 'that' far off the bike (more of a half-a-bum-cheek kind of guy), so I'm not sure how this would work if I did. Hmm, I can feel another track day coming on... I'd be interested to see what other methods people use. Playing with different styles is all part of the fun.

The bike will corner quite happily with the front in the air (my old gixxer was great for it). Because the front wheel is (hopefully!) still spinning, this helps to stabilise the bike. Turning the bars will still adjust the lean (and hence the path) of the bike although the effect will be far less than if the tyre was touching the ground. Whenever both wheels are on the ground, the traction (grip) is shared between the two, depending on the contact patch and weight distribution. As you get on the gas to exit a corner, the rear is taking most of the load, which is why you very rarely see front end wash outs at the exit of a corner (I can't remember seeing any). In the case of losing the front end, nearly every case occurs whilst the rider is still on the brakes just as (or just before) the bike has completed it's turn (asking too much of the front tyre). The critical point of any corner is from the moment you release the brakes to completing your turn to getting on the gas. Not surprisingly, this is also the time when you generally have the most to think about and work out. I think this is what Keith is getting at by saying that you need to have a plan for the corner, it removes some of this thought. Instead of thinking "What do I need to do now?", you should be thinking "What am I going to do next?"... Once you're on the gas, the rear will almost always be the first to let go (unless you hit a patch of oil or ride over a Roo...), another good reason for getting on the gas as soon as possible.