I A rider cornering at maximum g

[Erunanethiel]

The rider is cornering at maximum available lateral acceleration so he is not able to countersteer to the "inside" in order to bring the bike to the vertical position. So he decides to push down to the road with his knee to bring the bike up, does that unload the tires by countering gravity and cause him to lose grip just as he would if he countersteered? Or wouldn't it be a problem since combined vectors of centrifugal force and gravitational force are in line with the motorcycle and pushing with your knee to the ground doesn't cause a problem?

 

[JRMichler]

I can tell you from personal experience with a recumbent bicycle that merely touching the inside foot down will unload the rear wheel enough to cause an instant wipeout. This particular recumbent would then end up sliding along with me perched on top. No scrapes (on me), no bruises. I did this several times before learning to keep my feet on the pedals and countersteer when it started to lose traction.

 

[cjl]

This is a bad idea, since any force applied by the knee will decrease the normal force at the tire, causing it to be unable to support the lateral cornering loads. This causes the tire to slide, and as JRMichler said, it will cause the rider to wipe out.

 

[berkeman]

So he decides to push down to the road with his knee to bring the bike up

Have you tried doing anything with your knee during cornering at the racetrack, other than feeling your lean angle? It's not very reasonable to try to get any leverage or vertical travel with it to push yourself back up, IMO.

The rider is cornering at maximum available lateral acceleration so he is not able to countersteer to the "inside" in order to bring the bike to the vertical position.

Unless you get in trouble, you will not be changing your lean angle mid-corner at maximum lateral acceleration and traction. You only start to straighten up after the apex as you open up your turn radius and power out of the turn, so you have the flexibility to use an outside bar push (countersteering) or outside peg weighting (body steering) or both at that time.

 

[berkeman]

It's not very reasonable to try to get any leverage or vertical travel with it to push yourself back up, IMO.

ADD -- Not withstanding Marc's antics in MotoGP saving slides...

ADD2 -- Valentino Rossi used to relax his legs like that going into turns too. I guess it's getting more common now...

 

[John Archer]

A bike, by design, "wants" to go straight. When cornering at the limit, you are constantly countersteering (push inside bar, pull outside), simply eliminating your countersteering will pick the bike back up.
You are already sliding at maximum cornering, pushing the outside bar and/or pulling the inside bar the amount needed to pick up from a corner is insignificant.
In a corner, taken properly, the front will have a bit more work to do until just before the apex, after that, the rear has a much higher load on it. (Hence the larger size)