mbeckers

I am running Pirelli slicks on my car and experienced uneven tire wear on the front left tire after one track event. My car is an 07 C6 with Z51 package. I had the car aligned before the event and it has about 1.6 degrees negative chamber in the front and 1.0 in the rear. I was running about 35 psi in front and 33 psi in the rear. The right front tire and rear tires were fine with no issues. Anyone have any thoughts as to what caused this issue?

AU N EGL

did the track have many HARD right hand turns?

where is the wear? inside of the tread, middle or out side of the tread.


Two other things:
also I believe those tire pressures are about 10 psi too much for cold starting pressure.

2nd, my guess you need more neg camber

front min of -2.0 more like -3.0 for those slicks and
rear -2.0

mbeckers

The wear was on the outside edge. The track has about an equal number of left hand and right hand turns. That was the max the shop could do for negative camber without modifications. Can I get more negative camber by removing some washers on the bolts that attach the A-arms to the frame?

rbl

Check your alignment again .. sounds like the toe is wrong.

Getting an alignment and getting a good alignment are two different things. My man here gets both sides exactly the same and within 0.05 degrees of my spec. You can easily get -2 degrees with the stock suspension on a 2006 Z51 car ... I did. That's too much neg camber (-2) if you're running on the street. Since you don't have problems on the other corners it probably is not a camber issue and -1.6 to -1.75 is about right..

For best results you should have those tires on the car and have them at hot pressure for the alignment. 1 PSI will change it so take your own good tire gauge with you and don't rely on the one they throw around the shop.

Todd Z

Your tire pressure is way to high. Should be 22f and 20r cold. That is a good start. What compound are you using? The pirelli's are sensitive to heavy cars.

mbeckers

Hi Todd Z. Actually I purchased the tires from you. They are the used tires from the Grand AM series. Any additional advice would be appreciated. Other than the wear on the outside edge of the left front the tires performed great...tons of grip when warmed up.

Todd Z

Check your PM

davidfarmer

you should consider removing any washers behind the upper control arm mounts, and get close to -2.0 camber if this is mostly a track car. As stated, you might then have trouble with wear on the street, but it sounds like you are already making sacrifices.

Too much toe out would cause the inside to wear, not the outside, so unless your tires are toed "in" that's not it.

I agree your pressures may be too high, BUT lowering them will only make your outer tire wear issue worse. I vote for more camber, and you may need to remove the washers and/or get camber plates to get adequate camber.

Sidney004

Here are Pirelli's recommendation for Homestead:
http://www.us.pirelli.com/web/motors...ssureform.page
It might be a useful baseline.