Here are a set of Pirelli Slicks I use for autocross. The fronts are 245 and the rears are 285 on stock rims. I've seen some unusual wear spots on the front. It took a while to get the pressures right, so I know they were low on a couple runs and the car was pushing bad. Is this wear from rolling the tires over from underinflation?

 

looks to me like (and im not a tire wear expert) like the TOE isnt set correctly on the allignment.

i cant really see the other outside edge of the tires...if the tire was underinflated both outside edges would be worn down, and more uniform the zig-zag of this wear makes it look like TOE to me.

anyone else care to chime in? Any tire experts?

 

how much turning ( cirlce/oval track? ) did you do? was it all to that direction?

 

The first things I'd be thinking are too little camber, driver abuse (not slowing enough for turns) and underinflation...probably a combination of the three. Unless your street tires are also wearing excessively at the outside edges (assuming that you also use this car on the street), I wouldn't be thinking that the car has too much toe-in (but you should have it set somewhere close to 0 toe at the front on an RX-8 used for autocross and the street). It looks like they're going to cord on the outside shoulder pretty soon.

How many runs are on the tires? I'm not familiar with those tires. Are they real slicks or DOT-R compounds? Also, why are you running 245s in front and 285s in back? The fast setup on the car in B Stock uses the same width tires front and back which also allows you to rotate the tires front to rear every event which maximizes tread life (and with something like Kumho V710s or Hoosiers, there will still be plenty of tread by the time the tires heat cycle themselves into rocks). The car is well balanced enough that it doesn't need wider tires in back, certianly not one that big. It doesn't have enough torque for wheelspin to be an issue with decent r comps in the dry. I'd imagine that a 245F/285R setup understeers like a pig.

 

They are non-DOT slicks. I got them from a Porsche Cup Racer. They didn't have that wear on them when I got them. I use them for autocross so I'm turning in both directions. They were underinflated for the first few runs and were understearing really bad. That more than likely caused the wear... maybe? They've got about 5 events on them (about 6 runs an event).