Rookie tire question:redux

[oregonduckman]

It seems like the sidewalls on my Michelin Sport's are pretty chewed up but there seems like good life left in the flat area of the tread. Also, since the last AX the tires seem to pick up lots of gravel when they get warm.

My question is are there other indicators besides the wear bars that warrant tire replacement? I would rather error on the side of safety but would prefer to wait until I know the tires are shot/unsafe.

Thanks,

Fast UPS a.k.a Joe Parness

[Irksome]

My question is are there other indicators besides the wear bars that warrant tire replacement? I would rather error on the side of safety but would prefer to wait until I know the tires are shot/unsafe.

Thanks,

Fast UPS a.k.a Joe Parness

Having destroyed a number of PS2s myself, I can tell you some things to watch out for. The shoulders are quite fragile. My tires would get chunks taken out on the shoulder (the first 1.5" of tread). These chunks would then slowly develop into craters, eventually exposing the belt. The layer of rubber is quite thin on the outer shoulder area.

I drove on my PS2s until I exposed 'significant' belt. In one case, on a front tire, a nail or rock had gouged the tire, and over the next month of street driving it became a 1" square of exposed belt, at which point I replace the fronts. On the rear, I got more of a ribbon along the shoulder edge, about 4" long, which clearly had removed all but one thin layer of rubber. When that 4" ribbon broke free to the belt, I replaced the tires.

As I was monitoring the situation, I was checking the tires twice a day. In both cases, the rest of the tire was in great shape. I still have the front tire with the 1" square belt exposure, and it has 50% life left except for that one little problem. But there is no way I'm putting it onto a car, it's just way too dangerous.

The weak shoulder on the PS2 is why I refuse to autocross with them any more. I've still got PS2s on the rear of my car, a set that has not seen autocrossing, and it is looking good for getting long life out of them for (aggressive) street driving. They just don't like heavy (severe?) cornering on rough asphault!

[Jad]

I think what is happening is that you are overheating the tire (on the outer edge) which causes poor wear and chunking.

This can be corrected with more camber or smoother driving inputs with less over/under steer depending on whether the problem is on the front or back.

So the tires probably aren't the problem, though the more stick they have and the softer the compound, the more the problem will be highlighted. Have a very experienced instructor ride with you to see if you are turning the wheel too much or pushing which will destroy the outer edge of any tire, or if you simply need more camber (or less body roll) for your speed and ability.