Robsalvv

Well if the rear is in the air while you're hard on the front brakes it's not going to be able to contribute to any braking at all!! If the rear stops spinning in this situation, then you're going to lose its gyroscopic stabalising influence on the bike... life might get a bit interesting in that circumstance! Cheers, Rob

Hi Racer. I think we're discussing the same side of the coin... I understand about the cornering forces - I just didn't appreciate that they were as important in the "slowing down in a corner" process. I figured that the wheel diameter effects were more important. Your post highlighted an important subtlety that I should have realised under my own steam! Throttle position doesn't necessarily equate to engine revs!! e.g. going up an incline with the same throttle position, the bike will slow down due to the load. Those cornering forces are basically a load. If you don't adjust throttle when you tip in, the bike will slow due to the extra load AND due to the smaller effective wheel diameter. I remember discussing this in a level 1 CSS class recently (in Australia), and that's where I got the impression that the wheel diameter issue was all important in understanding why a bike slows down in the cornering process for a given engine revs. Perhaps Steve Brouggy dumbed the discussion down for simplicity... At any rate, I'm happy to have broadened my understanding on the issue. I guess this highlights how even more important rule #1 is. Rock on!

As the rider goes through the wet patch, the rider needs to be on rolling on and have the bike standing up as much as possible for that corner/speed combination. - so he/she needs to be locked on, back in the seat, cheek off, body :- down, forward and to the inside, eyes locked onto the exit target and rolling on. If possible, doing the level2 last session "pushing away" so the bike is even more stood up.

Yeh, there was some funny stuff in this thread I wish I had another year of high performance track work under my belt... sigh. Just on the wheel diameter thing, if you've got a constant throttle, therefore a given amount of fuel going into the engine, the bike MUST slow down as you tip it in. Discounting the cornering friction forces side of things, the bike would have to slow down anyway because the engine revs aren't changing, but the rear wheel diameter has effectively reduced... so you cover less distance for each revolution. See? The speed you eventually settle down to depends on how far you lean. Conversely, for a constant throttle, you'll start to speed up as you stand it up. The flip side is the one you mention, that if you hold the (true) velocity steady as you're tipping in, the revs must go up as the lean angle increases. A smaller wheel needs to go around more often for the same speed, so for a given lean angle and speed, you'd need more throttle than if you were travelling in a straight line. As to what would happen if you had a huge flat play area, marked out a large diameter circle, countersteered the bike into a known and constant lean around this cirlce and kept going round and round rolling it on... You'd eventually bump up against the rev limiter in 6th {that would be near 300km/h on my bike! Yikes!} and the sudden automatic "roll off" could be a bit exciting!! Before that happens, it'd be better to gradually reduce the roll on till you eventually stop and hold a steady throttle position. There'd be some weight transfer forward as the bike gently sorted out it's dynamic situation until it settled into a steady contstant velocity. We've been well taught to roll on once the turn has been finished in order to put the bike into it's ideal traction picture, but there's nothing to say that a bike wouldn't happily keep turning a corner with a neutral weight transfer picture, i.e. constant velocity, instead. Thoughts???? Cheers Rob

In answer to the subject, I use rear plus front if slowing down in a straight line, or for slow speed manouvering. Otherwise it's all front. A lot of riders in my neck of the woods still talk about using rear brake in a corner for: washing off speed if too hot, to aid tipping in, or to stabalising the bike on exit... I just don't understand this logic. I think these guys are lucky that modern tyres have a lot of traction available and that at typical highway / twisty road speeds, the available traction covers a multitude of sins! The rear to help tip in gets me shaking my head... I reckon those guys don't actually know that when they have the "oh ######, I need to tip in more" moment and go for the rear, they are unconsciously also countersteering more, otherwise going for the rear must make you go wide with the weight transfer forward... Using rear to wash off speed might work to a point, but is a bit dicey since the rear is being unloaded. The stabalising the bike on the way out doesn't make sense unless they're spinning it up, but generally they aren't. Good throttle control on modern bikes with good suspension shouldn't need any rear brake being dragged since the bike should be well planted already! Sure skilled racers use rear brake, but that's to initiate "backing it in" and then to control wheel spin on the way out... they're certainly not trying to wash off speed! ...I don't know, am I missing something??

Interesting thread. Hope no one minds me dredging up the past... new to the forum and surfing the board. Let's see if I have a grasp on the main points... Cobie asked a question about the weight distribution at constant speed on a straight line... if you discount drag, the f/r distribution would be about the same as if standing still, i.e. about what's neutral for that bike and rider combination. There's no intertial forces when the velocity is constant. If you hold a constant throttle and tip into a turn, a bike will slow down due to the smaller diameter of the tyre and also the cornering friction forces. The weight distribution will be biased toward the front by some amount proportional to the decelleration. If the lean angle and throttle are kept the same, the bike will eventually reach a steady state situation and settles down to a constant veloctiy, so the weight bias balances back to a more nuetral footing. The initial cracking of the throttle (once the turn is done) is to cancel out the slowing down bit. It goes without saying, that the gradual rolling on is to set the ideal traction picture and stablise the bike. As kept being drummed into us during CSS level 1 (and later) the number 1 job of the rider once the turn has been completed and throttle cracked is to stabalise the bike by gradual roll on of throttle throughout the remainder of the turn. ... anything else? Cheers Rob

Well, why not just jump straight into the deep end with the first post Assuming riding on the RHS and since I missed both the water and the bus when I looked through the corner, I'm assuming it's a blind right hander. Best possible traction would be off the brakes, gradually roll on the throttle, hook turn and/or lean off the bike pushing it away from you to put the bike up right as possible. Don't look at the bus or the water!! According to one of the posters in the thread Killerdude linked to, the poster would apply a heavy dose of rear brake to help tip it in further. ?! ... I gotta say, my eyes bugged open when I read that...! I think that guy is lucky to be posting the story he did!