What causes "cupped" tires?

Dear Car Talk

Dear Car Talk | Aug 01, 1993

Dear Tom and Ray:

What is the cause of "cupped tires?" We drive a 1988 Chrysler New Yorker. We rotate the tires every 5,000 miles. At 23,000 miles the Goodyear tires cupped and were replaced by Goodyear. Now, at 45,000 miles, the tires are cupped again. Chrysler blames the tires. Goodyear blames the weak struts on the Chrysler. Your opinion please? We have driven for years and never had tires cup.

RAY: Well, they're blaming each other, Jane, because they're really both to blame.

TOM: Cupped tires are usually caused by bad struts. The purpose of the struts is to keep the tires from bouncing off the ground when you go over bumps.

RAY: If the struts are really bad, the tires can literally bounce up and down like a basketball....badaboom... badaboom...badaboom... badaboom. And each time the tires hit the ground, a little bit of the rubber gets scraped off. Eventually, you get a lot these little scuffed spots, and that's called "cupping." And as you know, cupped tires make a lot of noise. It sounds as if a cement truck is on your tail.

TOM: So it's clear that bad struts can make this happen. But to be fair, cheap tires cup more easily than good tires. And while Goodyear makes some very good tires, they also make some real cheap ones. And unfortunately, most original equipment tires (the ones that come on new cars) tend to be of the cheap variety. So I wouldn't be surprised if the tires you've got on there are not all that great.

RAY: But Goodyear already kicked in a set of tires, so you really can't ask them to do any more. At this point, you probably need both tires and struts. And in both cases, it's time to upgrade.

TOM: The old Chrysler New Yorker is not known for its firm struts. So I would replace what you've got with a good set of heavy duty gas struts. You've got to spend a couple of hundred bucks to get a good pair, so don't fall for those $7.95 specials at Moe's Struts And Hair Care Center. With firmer struts, the ride may not seem quite as squishy, but the car will handle better, and your tire life ought to improve.

RAY: At the same time, I'd invest in a good set of tires. Goodyears are fine, but don't buy the cheap ones. Plan to spend 100 bucks a piece for above average tires. If you do that, cupped tires will no longer be what you runneth over.

TOM: Oooh...that was bad. Very bad.

Get the Car Talk Newsletter

Got a question about your car?

Ask Someone Who Owns One