Quote:
Originally posted by rmp
The technique is called "overdriving the brakes" and it is not particularly effective, but can be enough to make a difference.
You don't need to jab the brakes on and off, just apply them as hard as you can and then try and drive.
The reason this works is as follows:
When crossaxled with open diffs there is effectively 100% drive to the wheel in the air and 0% to the wheel on the ground. Purists will say there is a little drive to the ground wheel and that's true, but not enough to make a difference otherwise we wouldn't be having this conversation.
Anyway, open diffs distribute as much drive through the wheel that is easiest to turn as possible.
So by braking all four wheels (foot on brake) you make all of them harder to turn, so the ground wheel is, expressed as a percentage, now easier to turn relative to its partner; the ratio is no longer 0/100, but say 10/90. Hence it gets more drive and hopefully you can move off.
The technique is also used for hill descents in autos, but not because of its torque-distribution characteristics, but because it is a good way to force wheels to turn slowly in autos, the engine braking not being the best with slushboxes.
I have found that the gentle use of left foot brake and right foot accelerator is of assistance descending steep rock ledges rather than the conventional feet off all pedals approach. Takes a bit of practice though. I feel that I have some control over the situation.