Originally posted by Lythion
I noticed on the grooved tires that the outside shoulders were not worn at all. This is what makes me suspect that 2 deg. might be a little too much.
When you inspect a tire for even tire wear, grooving doesn't really count.
If you look at every tire that has grooving on it, you will notice that the grooves only form on the inside. They are never formed on the outside. What this means is that too much weight is being transfered to one side, and during high speed cornering, the tire is folding under on the outside tire (the side wall is not supported enough so it flattens out). Also, as it folds under from the outside edge, the tire tread shifts inwards and the inside tire's sidewall gets pushed over and since the sidewall is so thick, it pushes out that little patch of rubber where all grooves form.
Grooving is a case where the insert is too soft, and you simply have too much traction for your equipment to work properly and consistently.
Having too much negative camber will never... never, be the single cause of grooving. I know because I've seen cars that have had 5 degrees of negative camber (they crashed) and they did not have tire grooving. The only thing that happens to a tire with excessive negative camber and proper tire inserts will be excessive inside tire wear, but not grooving.