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September 5, 2008

Tire Whisperer: How To Read Your Weird Wear Patterns

By Jen Dunnaway

Editor

With all the hype about gas mileage and tire inflation, everyone’s familiar with the kind of tire wear caused by overinflated and underinflated tires. But do you remember what your rollomundos can tell you about some of the less obvious suspension and alignment issues? Read on for a quick refresher.

Shoulder wear (outer edge more worn down than inner). Usually due to excessive positive camber—the wheel is angled inward from top to bottom. Check the alignment, but also look for thrashed control arm bushings, bad tie rod ends, and bent suspension parts or body structures (i.e., shock tower pushed out of place from crash damage). Shoulder wear can also be caused simply by frequent hard cornering. More…

Wear on the inside edge of the tire results from excessive negative camber. Check alignment, but also consider whether shock, struts, or springs needs replacing—a sagging suspension can cause wheels to squat out under the weight of the car, and if this is what’s going on, it’s futile to try to compensate with alignment.

Feathering: this refers to a specific kind of directional inner-edge wear—when you run your hand over it, it’ll feel smooth in one direction, rough in the other. It comes from the tires scrubbing due to an incorrect toe adjustment.

Cupping: this bumpy or scalloped tread pattern results from the tire dribbling up and down as it rolls down the road. A severely unbalanced wheel can be the culprit, but worn-out shocks are more likely.

"Heel and Toe" wear: this refers to a directional choppy or saw-toothed wear pattern where the leading edge of the tread block is rounded and the trailing edge is pointed, often leading to vibration or wheel-bearing-like noise. It’s most often seen in low-profile tires, particularly the rear tires of FWD vehicles. It can be prevented by rotating the tires regularly, though this won’t help much once the condition has already developed.

Well, I think that covers some of the more common ones. Got any tire wear issues and suspension fixes that aren’t mentioned here? Share them in the comments.

Comments

steve preston
Sep 22, 2008 at 3:10 am

Heel and toe wear!! Thank you very much! Now I know what I have. My ’07 Ram only has about 13k on it,but it has low-profile 20″ Goodyears,and the outer edge of both front tires have a saw-tooth look from the side.

GTwildfire
Sep 13, 2008 at 5:26 am

Jack, I don’t doubt your professionalism but you’re wrong.
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Underinflated tires do heat up but that heat can’t repressurize the tires because it dosen’t expand enough. Also, if it could the tire would be repressurized and the source of overheating would be diminished, meaning the temperature of the tire would level out. The problem is that the air may compress a little but at low pressures air leakage could start at the beads (where the tires meet rim edges), as well as the breach that caused the loss of pressure wherever that may be (bad valve stem, poor stem seat or cut in stem, nail or slash to the tire, etc.)
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I tried to be general about this but I guess I was too general.
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I, too know a bit about tires. They’re the most important part of the car and I’ve owned 26 of them.

Derrick
Sep 8, 2008 at 9:21 pm

Jack is a complete moron. An underinflated tire doesn’t gain enough pressure to cause a blowout, it blows out due to the friction and wear of the sidewalls from being low. As a tire proffesional you must not be very successful, but a great comedian because you had to be joking with info as stupid and wrong as that.

ryangood187
Sep 8, 2008 at 5:14 am

oh and its weird how this bulletin is brought to you by BFG but the tire on the picture is a Yokohama YK420

ryangood187
Sep 8, 2008 at 5:10 am

jack your comment makes no sence, i too am a tire professional, i work for discount tires. an underinflated tire does blow out yes, it weakens the side wall and eventually brakes it down to a fine powder, now an underinflated tire cannot gain more than 2-4 pounds of pressure. there is no way an underinflated tire can reach its mamimum pressure, its impossible. unless you drive with a compressor hooked up to it as your going down the road.

Jack
Sep 6, 2008 at 4:43 pm

gtwildfire, added some relevant points but might be a bit off on his explanation.

Low pressure does cause extra flexing which leads to higher temperature. This higher temperature does two things: 1) it weakens the rubber compounds and 2) it increases the air pressure. So, an underinflated tire blows out because after the pressure increases the weakened rubber can’t resist the higher pressure.

In my opinion as a tire professional, I consider underpressure to be considerably more dangerous that overpressure unless the extra pressure is beyond the tire’s recommended maximum.

I’ve written more about this in an article on Inflation Pressure (www.tire-information-world.com/inflation-pressure.html), if you’re interested.

gtwildfire
Sep 6, 2008 at 7:01 am

there’s also middle tire wear due to overinflation, outer edge wear (both sides) due to underinflation.
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Both conditions can be very dangerous. Overinflating means that when the tires warm up from use on the road, the air pressure gets even greater, further increasing the chance of structural failure. Underinflation causes more friction, the sidewalls to compress under the weight of the car more than normal and the steel reinforcement in the tires to stress, creating heat and if the pressure is low enough the tire can blow out also.

Nes
Sep 6, 2008 at 1:59 am

Does dimples on the tires from burning out/peeling off count as tire wear? mine has a grip due to that!

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