I have 275/40/17 tires on 9.5 x 17 rims on the front and this is the 2nd set of tires that are cupping . I have had the first set of tires balanced once and the 2nd set balanced twice and a wheel alinment done three time over the life of both sets of tires tires . Does any one else have trouble with tires cupping?

 

bad shocks

 

yea.. your shocks are letting them bounce... time to replace those

 

i had a guy look at the tires and he said they are feathering not cupping on the out side edges but didnt know what causes it

 

feathering is another term for cupping

 

feathering is term used for when just one edge of a tire wears prematurely... you see it alot on large trucks... after a while though it will bounce and cup the edge of the tire. Looks to me like you need to get the wheels readjusted. should be fine then. although if you have pretty old shocks. wuoldn't be a bad idea to get new of those too.

here is the finition for feathering, which is not the same as cupping BTW but can lead to it.

Feathering
Feathering is a condition when the edge of each tread rib develops a slightly rounded edge on one side and a sharp edge on the other. By running your hand over the tire, you can usually feel the sharper edges before you'll be able to see them. The most common cause of feathering is incorrect toe-in setting, which can be cured by having It set correctly. Occasionally toe-in will be set correctly and this wear pattern still occurs. This is usually due to deteriorated bushings in the front suspension, causing the wheel alignment to shift as the car moves down the road.

 

Could the feathering be caused by going fast on a tight clover leaf on an overpass ?

 

you might wear the outside edge a little more than the inside.. but not enough to actually feather the tire... You would have to do it so much that all you would be doing is going arund the cloverleaf constantly.... so no. probably not to any noticeable degree.

 

If you have rust in your front 1/4 panel, it can eat at the structure and cause your tires to run a little crooked.