Cupping

[Gerald Pierce]

Had vibration since getting new tires about a year ago. Been balanced numerous times, even force balanced. One thing that keeps sticking in my mind is the guy at the tire place said "had a hard time getting one to balance, but it's good now".



Been deployed for a good bit of the time, but now that we are in for a little while, I drive from FL to VA quite a bit and the vibes at 68-75 are miserable.



Looked at the tires last night, I have visible cupping on right rear tire, the inside edge.



Shocks are new, alignment is about 6 months old (been parked for a good deal of the time 3-6 weeks at a shot).



Could this be from a defect in the tire or should I be looking at the suspension? OEM Goodyears all cupped evenly, that is what drove the new shocks.



I am tempted to go make them replace the tire, but that brings to mind another issue. If they replace one, should they replace both rears? I have the 4.10 LS rear end.



The tires are SUPPOSEDLY made by Cooper for Discount Tire (Pathfinder SUV Sport's

 

[Woppy V]

From what I have gathered the OEM Goodyears are known for cupping. I am doing a TT/Shackle this weekend so I can get new larger tires even though I have plenty of tread left. However... did you buy your trac used? has it been thru and accidents? If not it's probably just the case of owning CrapYear tires....

 

[Todd Z]

The RR tire had to be on the Front at one time to cup, IF not you have something seriously bent in the rear of the truck....



It is more than likely an alignment issue now, The problem is the ST is not Camber friendly from the factory, meaning it is not adjustable... The camber and toe are what tears up the inside edge.



SO a place will say it is in spec for an alignment, but it is not a "preferred" alignment.



Only way to get rid of it is to install camber kits and get the preferred alignment..



Todd Z

 

[Gerald Pierce]

Todd, you are correct, the tire has been both front and rear. I guess I'm going to have to get another alignment and make sure it is on a gnat's a$$ after they install the camber kit.



My only concern was the RF is not cupped, so that is why I thought it could be a tire issue.



Thanks for the info....



gp