Tor,
I forgot to give you the general philosophy for adjusting handling
with tire pressure.
Through most of the normal pressure range, the higher the pressure,
the stiffer the sidewall and therefore, the more stick from that tire.
As the tire rolls over under cornering loads, it eventually, gets to
the point where some of the tread at the inside will not be in contact
with the surface, reducing contact area and cornering ability for that
tire. By stiffening the sidewall, you allow the car to corner harder
without that happening.
If a car is not inclined to turn (not referring to just the front
wheels but the rotation of the car.... the front and rear tire slip
angles acting in concert to turn quicker than just the front wheels
alone), and we're ruling out suspension adjustments, lowering
pressures in the rear with respect to the front will generally make
the back give up some grip (it is assumed that the front pressure is
optimum for producing the best grip) allowing the car to turn more
willingly.
If a car is too quick to oversteer, bumping the rear pressure up will
stabilize it more.
If pressures in a given tire are high enough, generally, *very* high,
the opposite effect will result. The tire will crown. Though it
won't distort and lift the tread under cornering, neither will it have
much tread on the ground in the first place. So it will have less
grip than a tire with sub-crowning pressure. I don't care to use that
side of the curve as a handling tool because it's more difficult to,
by driving technique, get a crowned tire to stick when you want it to,
than a slightly underinflated tire.
To know which side of the curve you're on, make only small changes,
evaluating the handling after each change.
Rod
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