What causes tyre wear in the middle of a rear tyre

[madras]

What is the reason for rear tyres on a RWD car wearing out in the middle long before the edges? Pressures have been correct, or if anything, under inflated.

Should I now swap them over to the fronts as they are more likely to wear around the edges?

Thanks

[madras]

In the evo M5 (E34) buying guide it says "Worn centres of the rears could mean the rear sub-frame bushes have collapsed"

[madras]

combemarshal said:

Another one, Over inflated!
The temps wont be the same all day, and I bet your not on Standard tyres/wheels, where did you get the presures from?
Different tyres need different PSI!

ok look, is it impossible to post on PH without someone assuming it's always the obvious answer?? I wouldn't have bothered if I thought that's all you could come up with, clearly increased pressure will force the centre of the tyre to be more prominent on the road surface

i always check pressures when cold, and if you checked them when hot you would end up under inflating them! P=K (T/V), K - constant, ideal gas law

Could it not just be hard acceleration in a straight line? Pressure were form a Michelin foot pump (won the autoexpress test for consistent accuracy and precision) that is frequently tested on other equipment/tyres for accuracy.

The car is on standard wheels and standard tyres

[madras]

combemarshal said:

madras said:

combemarshal said:

Another one, Over inflated!
The temps wont be the same all day, and I bet your not on Standard tyres/wheels, where did you get the presures from?
Different tyres need different PSI!

ok look, is it impossible to post on PH without someone assuming it's always the obvious answer?? I wouldn't have bothered if I thought that's all you could come up with, clearly increased pressure will force the centre of the tyre to be more prominent on the road surface

And theres your answer.
But have you checked them when hot?
If not how do you know what presure they end up at after a bit of thrashing, don't forget recomended presures are for road use and biased towrads economy.
Try nitrogen.

Thats the end of any more ideas on this thread

Edited by combemarshal on Wednesday 28th February 13:26

they are 5psi higher when warm, as you'd expect. Tyre pressure are supposed to be checked when COLD, not checked after a thrashing.

Thanks for your suggestions guys, I'll check the wear out on a new set.

Edited by madras on Thursday 1st March 08:30

[madras]

GreenV8S said:

madras said:

they are 5psi higher when warm, as you'd expect. Tyre pressure are supposed to be checked when COLD, not checked after a thrashing.

That depends whether the reference pressure you're using is a hot or cold figure. The figures you're likely to be quoted for an ordinary road car on standard tyres will almost certainly be cold ones.

yes as said in earlier post, they are COLD

[madras]

splatspeed said:

spinning the back wheels

i used to get this on my mr2 turbo

i play a lot

middles allways go first

and lasted 5000 miles

that makes more sense. no geometry problems then. thank you.

[madras]

Roberto Rica said:

Hi Madras

They might be over-inflated - surprised you couldn't work that out for yourself.

Rob

are you a comeidan, or do you just not read the threads?

the tyres are not over inflated it's due to ripping the car all the time and spinning the rear wheels
just wanted to check if anyone thought it might be a geometry problem.
surprised you couldn't work that out for yourself by reading the thread.