increasing tyre pressure = smaller or larger slip angle ??

[KnifeEdge_2K1]

does increasing tyre pressure give a smaller or larger slip angle to the respective tyre ??
i believe that increasing the pressure will give a larger slip angle due to the smaller contact patch but recently i read an article that gives teh opposite view ...

[BlueSubaruSTi]

I think it has more to do with changing the pressures of the fronts as opposed to the rears in pairs.

[KnifeEdge_2K1]

it doesnt say anything about the front or back, just an increase in tyre pressure will give smaller slip angles for those respective tyres

[Alastor]

does increasing tyre pressure give a smaller or larger slip angle to the respective tyre ??
i believe that increasing the pressure will give a larger slip angle due to the smaller contact patch but recently i read an article that gives teh opposite view ...

It seems to me that decreasing the size of the contact patch would also decrease the corresponding slip angle.

My reasoning (right or wrong), is that if the contact patch is shorter then there has to be less tire deformation (all else being equal).

That is the slip angle is a measure of tire deformation possible due to the elasticity of the rubber. For a given loading and modulus of elasticity, the shorter contact patch will experience less deformation and produce a smaller slip angle.

I guess this same reasoning would apply to a simply loaded cantilever beam.

EDIT: One quote is enough...

[nota]

Forget theory - from practical experience I assure you that (within sane limts) it is higher pressures which reduces slip angle, minimises sidewall distortion

[datman55]

Depends on the tyre also......some tyres work better at higher pressures than others. Different cars even work better at different pressures when running on the same tyres!

Best thing to do is get it on the track experiment. We change tyre pressures by as little as 1psi in the race car to achieve the right balance. We have a target "hot pressure" and we chack all tyre pressures and temps as soon as we come in to the pits. We always try to make adjustments to pressure while they are still hot.

Mark.

[fpv_gtho]

Screw all this techno babble.....If the tyre's more solid it doesnt move around as much :p

[magracer]

I think the answer would be that the "right" pressure would yield less slip angle. Under-inflating gives you a deforming tire that slips, overinflating gives you an effect called balloning which reduces the size of the contact patch.

As Datman55 said, you have to target a certain pressure when hot, which should be at the optimal operating temperature as provided by the manufacturer. Different cars have different weight and different suspension settings so they use tires differentely; they should have different "cold" readings. Warning, if you start with too high pressures you will be faster in the initial laps, but then, as others reach optimal temps you will overheat (or balloon) and lose grip.

[MrKipling]

^^^ Believe what he says