What makes rear tires "cupped" on outside or inside edge? (I believe they've been on the rear the entire time) They are on a Dodge minivan with a solid rear axle, so I wouldn't think there would be any alignment to deal with. Rear doesn't bounce, so don't believe it would be shocks. They tread is still good, but they are so noisy I've got to replace them.
I'll have to disagree on that one. Underinflation will cause the shoulder or sidewall of the tire to wear evenly and over inflation will cause the middle of the tread to wear evenly.
Cupped tires are usually the result of a bad shock/strut. They can also be caused by a ball joint or other suspension part.
Approximately 8/14/03 06:29, M.Burns uttered for posterity:
Unless you are built like "Refrigerator" Perry, it is impossible to properly test shocks with a simple bounce test. You just don't weigh enough to put enough force on them to even begin to simulate the weight shift of your vehicle.
Try backing up in an open area then hit the brakes hard to check rear shocks.
Worn suspension, worn shocks usual cause, severely out of balance another. Shocks highest on suspicion list, but also check for excessive play in the rear suspension. It usually also takes poor alignement to cup the inner or outer edge, if the alignment is good but the shocks [or similar] are bad, the cupping tends to be along the middle. Have a tire guy take a look to see if they are more feathered than cupped... that would be alignment.
No, Robert, we are not all 'full of shit'. People have posted what they have seen as the most likely causes of this problem. Faulty tires can be one of them. There are so darn many tire brands available today, and so little objective information on most of them.
Crappo tires are bad economy. Paying a lot of money doesn't necessarily guarantee quality either.
That's my point how do you know that faulty mechanical problem are the most likely cause of cupping? You offer no evidence. I at least have anecdotal evidence: In my case Sears exchanged the tires for a set of BF Goodrich TA's (plus upcharge) drove them 38,000 smooth miles with the same shocks. In the case of the 442, I drove the car 20,000 more with the original shocks and then changed to Bilstein gas charged, What great shocks. I haven't seen anyone definitely prove cupping is caused be worn anything. Just because manufacturers and Experts (read trying to sell you repairs [that is not to say the customer doesn't need the repairs]) say cupping is due to poor mechanical maintenance does not make it so. Along with the repairs you sell the customer new tires and the manufacturer is absolved. They will never take responsibility for anything! Bob Zawarski
You have anecdotal evidence in one or two cases. People on here usually have years of experience, and know what is normally the cause of these problems.
Your posts are juvenile in their venom.
So, you had a couple of problem. So F****** what! All of us have seen different aspects of this sort of problem. Yours goddamn surely isn't the only answer.
I'll agree with this poster. Most of the "cupping" or "feathering" that we see on vehicles in our shop is not due to suspension or shock failure. It's due to bad alignments or not enough rotating. Some of the 4x4 trucks are really bad and will tear up the front tires quite quickly if they are not rotated at least every 10K kilometers.
And then there are the shitty tires that are being installed all over the place. Even the manufacturers use some really lousy tires as their "factory" installed tires.
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