I picked up a set of spare stock wheels last week. They happened to come with the stock tires. The rears are pretty much shot... down to the wear bars for most of the width, and then below the wear bars on the *outer* edge. Looks like the original car had some flat camber numbers. The front tires are in fine shape overall. Anyways, I've got an Evolution Phase I school coming up at the end of the month. Will it be safe to run these tires? I'm assuming right now it will be dry. If it's wet, obviously not. But if it's dry, how well do the stock S02's grip when they're down to the wear indicators? I don't want to ruin my Evo education on crappy tires, but I also don't want to abuse my other good set of S02's if this worn set can handle it. Thanks.

 

You're in luck. For autoX purposes, worn S02s work much better than newer tires. In fact, as long as it's dry, the more worn the better. Recently a very good local autoXer was shocked at how much slower he was after switching to newer S02s.

 

[Monty Burns] Excellent! [/Monty Burns] That's what I was hoping. I know on some tires, the tread compound tansitions to a less sticky rubber as they wear. I wasn't sure about the S02's.

 

The only problem I've had is that by the time they're worn that much, my S02s were so heat-cycled that they became really hard an slick.

Shaved new S02s are probably a really good non-R compound auto-x tire.

 

I disagree.

I find that worn out SO2s do not offer as much grip as 1/2 worn tires, even in the dry. Perhaps it's due to our high ambient temperatures down here, but my tires are pretty well shot even before I get to the wear bars. I think Elistan is correct about the heat cycles doing them in.

This may be true, at least untill the mold release compounds are worn off a new tire.

That doesn't mean that you shouldn't use nearly worn out tires for an autocross school, in fact they may be a good training aid for controlling oversteer .

 

Street tires aren't as prone to the heat-cycling problem as R-compound tires (they simply don't heat as much and the driving typically done on them is less conducive for heat build-up). However, how much is too much is the basic question. I'd go for it...

 

Well, I've been autocrossing for two years now, with the last six months in the S2000. I've become pretty familiar with the limits of adhesion with my good set of S02's. I'm going to get a UK alignment done this week, and slap these worn tires on there. There's an autocross this coming weekend (8/17) so I'll run the worn tires there, and get some mental data points before my Evo school (8/23).