: Tire cupping

09-30-12, 12:25 PM
Ok I replaced my right rear shock about 3 weeks ago. I have no idea how long the shock had been out , but I took it to the dealership after about 2 months of hearing some slight rattling in the right rear area when I had the radio off, which was almost never.
I was also experiencing shaking in the steering wheel at highway speeds, for about 2 months as well but I never drive on the highway so i never really noticed the shaking. So the dealer inspected my car found the bad shock and re-balanced my tires, the day after I got my car back I went on a 600 mile road trip, of course the shaking in the steering wasnt fixed and made my drive pretty bad.
When I got home from my trip , I went back to the dealer and they tried to fix the shaking in the steering wheel. The service advisor told me that they had to force balance the rims/tires and that I almost needed new tires(brand new tires bought like 6 months ago). So ok I leave the dealership and there is a very slight shake to the steering wheel now , barely noticeable but if you are like me you know most of the sounds your car makes..
Sorry for the long story but it provides background information that was helpful to the problem so anyway I found a nail in my tire the other day and went to sears where I bought my tires, the rep told me that my tires were cupping, he didnt say which ones were cupped and I had not idea what that was until i got home and googled it.

I guess my question is since I had my rear shock replaced do you think my tires will continue to cup or did replacing my shock fix that problem ? Should I have my struts and shocks checked by the dealer or someone else ? I am going on a little roadtrip at the end of the week and i'm now kind of worried about my tires which have like less 10k miles driven on them.. Any advice would be appreciated, thanks for your time.

09-30-12, 09:07 PM
Cupping is a wear pattern where the tread is higher on the edges of each tread . It's not uncommon in poor quality tires. Bad shock/struts often lead to it, too.

Replacement is the only real cure to the vibration. It could be just one or two tires. Consider checking with recyclers or big tire shops for used tires like yours.

I once heard.read some shops offer an innovative service for AWD car owners who've ruined one tire. Since AWD car tires should be replaced as a set, it can get very expensive. This shop supposedly would sell a new replacement tire, but put it on a machine to wear it to match the existing tires on the car. I've never really had to look for just one.

10-01-12, 04:28 AM
Cupping is a wear pattern where the tread is higher on the edges of each tread . It's not uncommon in poor quality tires. Bad shock/struts often lead to it, too.

That's feathered wear, cupping is almost like someone scooped off part of the tread as if using an ice cream scoop, and it's caused by bad shocks and or struts.

10-01-12, 06:52 AM
Cupping - the low roundish areas on the outer tread bands, usually caused by worn suspension parts, can also be caused by excessive toe-in.

10-01-12, 06:55 AM

10-01-12, 09:21 AM
So the right rear shock was replaced but the front left tire is cupping.. Would the right rear shock cause that problem or do ya'll think my front left shock could be out too ? Like I said tires bought within the last 6 months good michelin brand tires, had a alignment done when I bought the tires and they have been rotated once since being bought all same size.

10-01-12, 07:37 PM
These cars do tend to wear the outside shoulders of the front tires if not rotated regularly.

10-15-12, 05:14 PM
There could still be a number of things wrong, that most reputable shops don't understand. If your tires are still cupping and you still have a vibration, you could have a bent rim (which these people should be able to tell). If rims are okay. What brand tires are you buying? These cheap Chinese tires you can buy are junk. Tires beads have to be uniformed to rim with a max tolerance of 2/32's of an inch. refer to page 78http://www.sullivantire.com/uploadedFiles/Bridgestone%20Truck%20Data%20Book.pdf
if the tire bead is not mounted correctly, this will cause irregular tire wear as will as vibrations