I went through one set of S03's in the rear of the car with weird tire wear in the middle and not the shoulders, I even lowered tire pressure to try to compensate for this wear. After an alignment I was told the car was off and that it was due to how the car was tracking in the rear that it was the problem. So everything was re-checked and put back in stock configurations for the rear, brand new set of S03's in the back now...but its looking like the middle wear is still happening and not on the shoulders like the middle.... I don't know wtf is going on, I know its not the tire because my fronts don't wear like that. I've heard others with this problem but I thought my problem was solved....any other ideas????

 

Sounds to me like you've still got the tire pressure too high in the back.
What tire size, rim width, and tire pressures, are you running?

 

stockers right now with 245 s03's running 25 cold psi...thats not too high, 32 psi is what it calls for stock.

 

I can't imagine what might be causing your problem. If the center of the tread is wearing out first, then it has to be bulging. I think I'd try 32psi. With 25psi in the tires when cold, they're going to generate more heat than they sould (because there will be excessive sidewall flex at speed) and that might be causing an over-inflated condition when the tires are hot (I'm just making wild a$$ guesses here). My car is DANGEROUS if I let the rear pressures drop to 25psi. The oversteer makes the car unmanagable. IOW, somehting ain't right.

 

yea, the car doesn't oversteer hardly at all....i might bump the pressure back up to see what the hell is goin on.

 

I hope somebody else can shed some light on this, because I haven't got a clue.

 

yea, ive heard other people having this problem before too.... but I couldn't find the thread to see what else was said at that time, that was like 4 months ago maybe sooner. I bumped my pressure back to 32 psi this morning.

 

Can you rent or borrow a tire pyrometer? By checking the temperature at both edges and the center of the tire, immediately after a "typical" driving session, you can see exactly what parts of the rubber are carrying the most load.

Wish someone who has experienced this before would throw in their two cents worth. I did find the following threads discussing tire wear and pressures:

http://forums.s2ki.com/forums/showthread.p...threadid=128526

http://forums.s2ki.com/forums/showthread.p...wear+AND+center

Seems that everyone thinks it has to be a pressure rather than alignment issue.

Good luck,

RED MX5

 

FWIW, I've had this problem, but with 255-45-17's on a 9" wide wheel. Most of the wear came over the months that I had the tires at 34 psi with two autocross days (pressure peaked at 40!!). Lowering the pressure to 29-30 psi has evened out the wear, but I could never even out the tread. I also think 245 tires on a 7.5" wheel tends to wear the middles.

 

well the 245 in a S03 is the same contact patch as the OEM S02 with the 225 width.... so that shouldn't be problem as its still OEM contact patch size in a 245.