Hi all,

I checked the rear tires of my 5000 mile old C2 this afternoon (Pirelli P Zero Rosso's on 19's) and was a bit horrified to see significant wear in the middle of the tires (especially since I've only had them on for about 4000 miles). It seems like the sipes in the middle tread blocks have almost completely worn down, although the deep grooves circling the tires (separating the blocks) are still at least 5mm deep. Do these tires need to be replaced or is there still life in them, given that the main groooves are still deep? The worn out sipes in question must be pretty shallow to start with.

I'm having a set of PSS9's fitted on Tuesday so I'll get the opinion of the guys there (Performance Automotive of Malvern PA), but thought I would check here too.

Thanks

Nigel

 

Nige--the 997/S is a tire abuser because the suspension really puts the to use. What pressures have you been maintaining? What sort of driving typifies your last 4000 miles? Track time? Highways?

I've got about 4400 on my Bridgestones and they look like they have not worn a bit. They are also a great performing tire.

 

Hi Dan,

As for pressures, I've been running 34F/40R, although I noticed they were quite a bit lower today (28/34)...I reinflated them and will need to check more often. If anything, the wear in the middle of the tire suggests overinflation which has definitely not been the case. in terms of driving style, I would I have been pretty easy on the car. A bit of sprited driving from time to time, but never any tire-abusing stuff.

Thanks

 

I recall many years ago underinflated tires also resulted in centers wearing out prematurely,--particularly when coupled with high speed driving. Centrifical force would drive the centers outward and prematurely wear them out. You have to find a balance in TPs. I believe that mine start the day at 36 and 40.

 

I have 23k on my potenza fronts and changed the rears at a 16k, i check every couple of weeks and keep them at 37/44

 

This may be helpful to you.

https://rennlist.com/forums/997-forum/270423-rear-tire-treadwear-poll.html

 

Thanks for the replies, guys. I actually had the tires checked out today by a Porsche specialist (who was installing my PSS9 coilovers and Fabspeed mufflers) and he said they still had some life in them. I'm hoping a should at least get to 8000-10000, since I,m not that hard on the tires.

 

Tire wear in the center could be caused by over-inflation.
In your case, it's definitely not over-inflated.

But if the wear in the center is "cupped" it could mean under-inflation.
We are all using soft compound rubber in high performance tires which actually require
a little more pressure to "hold" the shape of the tire for better surface contact.
(Soft rubber is also the reason why your wheels shimmer when first driven after being parked for a long period of time, then the shimmers go away once the tires warm up.)

It's hard to explain in written words, but soft rubber gets soft when the tires are hot,
and can change it's shape or "bulge" causing uneven wear, especially in the center.
When it gets cold again at rest, it contracts back to its normal shape,
which explains why it's worn yet it's cupped.
A higher air pressure will "hold" the shape better when the tires are hot.

**This is not my theory, my previous BMW mechanic recommended it to me when my tires were all prematurely worn like this. After upping a couple psi to the tires, I have gotten rid of the problem!