Tires: Cupping, 2006 buick terraza, buick terraza

Question
Barry, I have read several of your responses in regards to cupping.  I have 2006 Buick Terraza Mini van.  We have had cupping issues since about the third month that we had the van (we bought it new).  We had the tires replaced at 10,000 miles under warranty.  At that time they aligned and balanced the tires.  It now has 21,000 miles on it and the tires are cupping again.  It is most likely the type of tires that they are putting on it, or is is most likely the struts, or something else?  If it is not the tires, would you think the warranty should cover other problems?  The dealer is not being very helpful.

Any advise or information is appreciated.

Greg

Answer
Greg,

Alignment is a matter if degree rather than kind.  "In Spec" merely means it falls within an allowable range, but even within this allowable range, cupping can occur - albeit more slowly.

I should also comment that some vehicles have fairly aggressive alignment settings - more geared to give good vehicle handling, at the sacrifice of tire wear.  I just do not have any information concerning how aggressive the alignment settings are on your vehicle.

Don't forget that rotation is a preventative measure and not a cure.

So I would look again at the alignment.  If it is not within the inner half of the tolerance, this might be the cause.