Do I need shocks?

carnut169 · carnut169's Garage

If you read my recent post about tires you know that I just purchased a new set of Kuhmos. I ended up buying a whole set due to a rear tire blowout because my front tires were cupping. When I purchased the wheel/ tire combo I had an alignment done and a high-speed balance, but the ContiSportContacts wore out in 8 months and 6,000 miles! Do you think that my car might need shocks? It has 65k on it now- but the front does not "bounce" up and down. What else could cause the front tires to cup?

Sean Hamilton · Sean Hamilton's Garage

I'm hardly a Guru on this Sean, but do you mean Concave - wear at the tyre edges and therefore under inflated? Or convex - wear at the tyre centre and therefore over inflated?
Inner or outer scrubbing I think means alignment / camber / caster / toe?

have I got that the right way round?

Somebody?

Superman · 04-24-2002, 07:08 AM

I was the one who suggested that toasted shock cause tire cupping. By cupping I mean that each of the hundreds of tread "mesas" ended up shaped like a cup. I'm not talking about wear in the middle of the tire, or on the edges. To me, "cupping" means the tire has many, many areas where the tread has worn into a bunch of cups. As far as I know, the only way this can happen is if the tire has actually been bounding up and down due to a shock that is effectively not even there. If a shock is operable at all, it will keep the tire from actually bounding and cupping. You've seen cars like this on the freeway, haven;t you? Where the tire is actually bouncing up and down on the road surface. I think it would be unlikely that both your front shocks are inoperable.

As a side note, this is the shock's job....to keep the tire against the road. Not to keep the car from rolling side to side, or bouncing or whatever. The job of a shock absorber is to keep the tire firmly against the road surface at all times.

Go to a tire store to learn about cupping. I suppose there could be other causes. Again, I suspect we're talking about different things.

carnut169 · carnut169's Garage

Neither. On the inside edge of the front tires they are "wavey"- in other words they have high and low areas.

carnut169 · carnut169's Garage

I can post a photo later if you guys do not know what I am talking about.

Superman · 04-24-2002, 07:26 AM

I photo would probably be helpful. There are many others who know much more than I about suspensions and tires, and that would include the more experienced tire guys at the local tire store. But there is a wide range of competencies in the tire store industry, so ask your local trusted mechanics who they take their cars to for alignment.