Code Red - Willow has always been hard on left side tires, due to turn 2 and 8&9 being long high speed sweepers. They put a lot of stress on those tires. When I have raced there we have always had to set up around this issue. Standing up the left side (less camber) and making some compromises to get reasonable tire wear. For sprint races it is not an issue, but for longer races it is something we have to address.

What has been interesting on the GT2 is it is cording the outside of the tire, where most race cars cord the inside of the tire. What I am learning is the GT2 is under sprung from the factory, and as a result it is simply rolling over on the outside of the left rear. It seems to work ok for 100 miles or so, but then simply kills the outside edge.

What was also interesting is the first time it happened I had a full tread depth MPSC (8/32nds). The tire was down to about 4/32nds of tread, but the outside edge was corded at 133 track miles (I trailered the car to the track). Tire pressure was 36 hot, per Michelin specs.

This time I had the left rear tire shaved and heat cycled at Tire Rack before it was sent. At 130 track miles the left rear was corded. The tread was well into the tread wear indicators. So the tire was essentially dead, so even if it had not corded there was not much life left.

Next time to the track, if I don't have new springs, I will run higher pressure in that tire and we will stand up the left side from the -2.5D of camber to maybe -1.8D. Some compromise to try to help that tire live a bit longer.

So I think the issue is a car set up issue and a track configuration issue combined. One requires a compromise to the other. This is not really the case at any other local track we run, just Big Willow.

Anyways I will keep working on it as I go back and see if I can get a setting that allows me to get a few more track miles before I have to pack it in. Last time I was going home at 12:30!

JCM

 

Just for my benefit, can you explain why running less camber will help outer edge wear? I would've thought the opposite - you need to run more camber to prevent outside edge wear. In fact, it's been my experiense running cars with stock suspension, not rear engine p-cars though so maybe there is something I'm missing.

Drew

P.S. Just noticed you're running quite a bit of toe in the rear - could that be part of the reason for hte wear?

 

Mafia,

Good point, outer wear would suggest the need for more camber. I am so used to needing to stand the left side up from the race car I didn't think that through. The amount of toe is consistent with what we have run on the race car. It provides good handling, but may also be a contributer given the limitations of the stock suspension.

JCM