Saturday, July 05, 2008

Chunking Tire

I finally unwrapped my tires from the Miller event. Here's a photo of my passenger front tire showing significant chunking both on the center band and the edges of inner tread block.

This is suprising because the stock suspension lacks enough negative camber for track work. This is confirmed by some significant wear on the outside shoulder of front tires. The opposite side showed very minor chunking -- 2-3 small chunks total.

I'm not sure when this occured -- I suspect it was saturday afternoon. It was really hot, 98 F, and blazing sun, the track was probably close to 120 F. I was pushing pretty hard as well. There was a little push in a couple of corners but nothing out of hand.

I think the centeral nature of the chunking indicates too much air pressure. Except -- you can clearly see the mold line separating the left and right halves of the tread. If the air pressure is really too high wouldn't you see enough wear on the center rib to obliterate the mold line?

Saturday afternoon I dropped pressures and ended up at 35 Lbs hot in front. I guess I'll drop to 33 but I'm concerned about anything that might increase wear on the outside shoulder.

1 comment:

mark said...

Kumho Ecsta MX? I didn't have any issues with those tires on my Mini at Buttonwillow -- but less power, less weight, cooler track. I did round off the corners of the front tires.

The worst chunking I've ever seen was on a 7 with some sort of grand touring tires at Laguna Seca. Several quarter-sized hunks of rubber were gone.