I just got my tires rotated and rebalanced and although this is the 2nd or 3rd time I've had it done in 16,000 miles total, my tires are starting to cup on the outside, on all 4 somehow! (the fool at wally world called it coupling and I didn't know what in the snot he was talking about until he showed it to me). Does anybody know how and why this is happening? I think it is usually related to the shocks or suspension. I can't believe my shocks have worn out at 16,000 miles. How in the heck is it happening to all 4 also? I got excellent wear out of my '96 and '00 trucks. I keep 32-35 lbs of air in them and i pull a 2000# bass boat maybe 800 miles a year and a 6000# travel trailer about 800 miles a year? Is this something I should take up with the dealer? I am trying to sell it right now and get a Lightning, so maybe I won't have to deal with it, and it's not too bad, but I am surprised it is there at all. If anybody feels this would be better suited for the suspension forum, please move my post.

 

Most tire web sites will say cupping on the outside edge is due to bad shocks. However, my wife's wife's mini SUV (Suzuki Grand Vitara) was cupping tires bad, even after I put new shocks on. I researched this and found it is a common problem because the manufacturer recommends ZERO toe in. On that vehicle, as the suspension wears, the tires actually toe out and wear the outside edge. The problem is fixed by adding toe-in.

Have your alignement shop check the toe-in; maybe even request they set it for the most toe-in recommend in the Ford specs.

BTW, your stock shocks might not be 'worn out', but they are very low quality, lousy shocks! If you plan on keeping the truck, good shocks are money very well spent, IMO.

 

Shocks are first suspect. But, there is another possibility. Once I had a dealer tell me that bad tires can cause it also. HE said Uniroyals do that. I had Uniroyals from the factory on a Chev at the time.

 

Albow, if your truck is running the Goodyear Wrangler RTS tires, that may be part of your cupping problem, and they are probably very noisy too. I have a 2000 that came with RTS tires and all 4 of mine are also cupped. I did all that you did and it didn't help. I ran them and listened to them for 45,000 and put on Cooper Discoverer AT's and so far am happy with them, much quieter even with the more aggresive tread pattern. Hopefully they will not cup. My tire dealer says that rotation is the most important thing to do. They rotate front to back and do not cross rear to front.

Cattail

 

Thanks guys. It's on the outside as one of you said, almost what I would call feathering instead of cupping. For some reason, I can't recall which brand they are, but it isn't one of the above. I have the 275/16/70's owl I think. I want to say they are Generals.