Tyre Pressures Correct But Middle of Tyre Worn. Advice?

[paintman]

helix402 said:

Not sure what the car bible is.

http://www.carbibles.com/tyre_bible.html (You'll need to copy & paste as it doesn't seem to give a clickable link)

[SebringMan]

GreenV8S said:

It may be that what you're seeing isn't the tyre circumference increasing, but the lower pressure giving a longer contact patch with more slip at the leading and trailing edges which would lead to wear in the center. (I suspect it's also that longer contact patch which is messing up the handling as you describe.)

Just to bring this back .

When I checked my M3 with the Falkens on the rear and 35PSi in them (book figures basically) there was still a gap between the centre of the tyre and the ruler. So the circumference did indeed increase it seems.

I've since put on some Michelins on the rear. On other cars they seem to wear very well, not just for longevity but also the wear pattern. They seem to last too.

[E-bmw]

SebringMan said:

When I checked my M3 with the Falkens on the rear and 35PSi in them (book figures basically) there was still a gap between the centre of the tyre and the ruler. So the circumference did indeed increase it seems.

Not quite sure what you mean here, but surely if you put a ruler across the tread at "correct pressures" then the pressure is too low, maybe I am misunderstanding what you mean by "circumference did increase" not sure.

[GreenV8S]

SebringMan said:

there was still a gap between the centre of the tyre and the ruler.

Is that another way of saying that the tyres had worn in the center?

SebringMan said:

So the circumference did indeed increase it seems.

If the circumference had increased then you would expect the tyre to be proud in the center. It seems to me that this test shows that the circumference had not increased and so the wear must have been from some other cause.

[E-bmw]

Glad it wasn't just me that was confused by that.

[SebringMan]

E-bmw said:

Not quite sure what you mean here, but surely if you put a ruler across the tread at "correct pressures" then the pressure is too low, maybe I am misunderstanding what you mean by "circumference did increase" not sure.

What I meant to say was that with the centre of the tyre worn out more I would have expected the tyre to be "straight" with a straight ruler put across them, and not to have a gap in between the centre of the tyre and the ruler.

But, going by the wear that was occurring the above made no sense unless the tyre was 'balooning' as the "Tyre Bible" suggested and would go with Helix's suggestion.