Tire Cupping

[Keith]

What causes tire cupping ? Every other set of tread on the outside of the tire is a diferent height. Makes a tramping sound.

[Keager]

I've read that it could be one of 3
-underinflation/or mechanical irregularities such as out-of-balance condition of wheel and/or tire and bent or damaged wheel
-loose or worn steering tie-rod or steering idler arm
-loose, damaged or worn front suspension parts.
check em out. weird tire wear though eh.

[TaylorM]

faulty suspension but the fact that yours is on the outside of the tires is a bit wierd given that at least the back tires should be set to a slight negative camber.
Is it front or back (or all of them) that you have this problem with ?
Do you have any other issues ? shimmy , pulling, excessive tramlining , brake shudder, rough ride ?