Originally Posted by lnewqban
Think of a leaned wheelie while leaving a turn: how can the bike be balanced on only one tire? Could that be done at extreme lean angles?
The point is that as we transfer weight over one tire (CG moves aft or forward), we also transfer the percentage of the lateral force that the tire is feeling, not only the vertical force.
Going to extreme examples is useful many times:
Being skillful enough to keep the steering and weight balanced, could you go around a turn in stoppie attitude only?
Could you go around the same turn doing only a sustained wheelie?
If so, which way could be a faster coasting and why?
Which way could handle the maximum lean angle and why?
Wheelie could be done at extreme lean angles if you were close to the balance point already. You couldn't *start* a wheelie with both tires on the ground and a 45 degree lean angle, simply because the acceleration required to loft the front consumes more traction that is available at that time(the rear would wash out). If however you were somehow able to already have front wheel high in the air to the point where there isn't much acceleration required to keep it there, then I would think you could probably do a 45 degree lean angle corner on one tire. At that point you're just a unicycle right?
What do you mean by which way could be a faster coasting?
I would think the rear tire would be handle more lean angle than the front just because of the contact patch size since the weight would be the same. For a given weight and tire/road stickiness, contact patch should affect available traction.(!)
I think you have definitely cleared that little portion of the problem up for me!
So for example, since we add more weight to the front by coasting and not being on the throttle, but the stickiness isn't changing and the contact patch doesn't change very much, it is definitely in a worse position than it was before.
So the crux of my misunderstanding lies here: Both tires gain more traction with more weight on them, but because the contact patches are of a certain size, we have the most traction when the weight is distributed in proportion to the contact patch size on the tires!
Now with that in mind, it gives me another question. Now remember we aren't discussing clearance, we're talking about a slippery surface where clearance isn't going to matter anyway, if you get close to touching a peg down you were already screwed. A wet, dark, freshly paved blacktop. Not a good situation there.
Consider that, when you coast, you are losing speed due to wind resistance, so undoubtedly from the time you enter a corner not on the throttle, you'll be going slower at the apex than you would otherwise, and have less lateral acceleration on the tires. Is that negligible compared to having the weight properly distributed per the contact patch sizes? I'm going to assume yes, going 15mph slower should have a much larger impact on available traction than having the weight distribution correct front to rear. Again I could be wrong. (again this ignores the fact that it is easier to recover from a pucker moment if you're on the throttle)
I'm starting to think the safest bike is one that has the rear tire on the front