tyre pressures

[advtracing]

76s , r-gruppe car , stripped out and weighting around 1000kgs . running toyos

235/40/17 rear and 215/45/17 front

can't get a good answer from the suppler re pressures to suit car and weight . whats your take on suitable pressures

[ian c2]

Have you done a temp and chalk test ?

[advtracing]

nope , don't race it so really doesn't get much temp . NZ conditions are also no hot

[McLaren-TAG]

Not sure you're going to get a definitive answer on this. As long as the pressure is "safe" from a tire manufacturer recommendation it's going to vary on what kind of driving you're doing, temperature, and whether you're looking to correct or introduce any minor over/under steer traits. It's a lot of personal preference really.

Over the course of a year I can see from as low as 24 lbs in the front and 29 rear to 33 lbs front and 38 rear for what I want the car to do.

BTW, R-grouppe has nothing to do with tire pressure.

[advtracing]

i was defining r-gruppe to visualize what i mean by stripped and 1000kgs

anyway manufacture is advising 36 which is to high for the weight , currently running 32

[ian c2]

I was referring to checking for over/under inflation using chalk or temperature .

I can give you 964 17" pressures for the different loads , and the lowest pressure will be most relevant if that gives you a ballpark to start from ?

Even in the rain last week I saw a 3psi increase on my commute to work ....

[McLaren-TAG]

The weight of the vehicle isn't the only factor, suspension settings alignment etc will all contribute as well. So the best way is to do the chalk test etc as suggested and drive the car how you're going to drive it and see that the wear marks reach the outermost tread point.

A lot of tires have markers built in so you don't even need to chalk. The R-gruppe thing was a little ribbing, not to be taken seriously.