Riddle Me This! Abnormal Tire Wear

[trebuchet03]

So I've got somewhere between 20K and 25K miles on my tires...

Since new, I've inflated them to 55/50 (F/R - 44psi rating).... I typically check tire wear at least monthly (except this month, I moved and haven't been paying attention).

So I just checked, and my driver's front tire has 1/32 extra wear on the outside (or you could say 1/32 less wear on the center).

AND my passenger rear has the same exact excess wear.... My tires are directional, I rotate Front/Rear (not side/side).

Any ideas as to why?, this is wear after two years of use at the above pressures. Would the explanation be different if it were just one tire? I'm not too concerned, there's plenty of rubber left and 1/32 isn't much... I'll just monitor more frequently to watch for any other change... If the difference gets up to 2/32, I'll deflate to "normal" pressure to see what happens (after eliminating the pressure variable).


Boo Hoo to you everyone that said I'd wear out my centers at these pressures

[metromizer]

You mentioned just moving... maybe your driving habits have changed somewhat, more in-town driving (where sharper turns eat the outside tires edges) versus longer hiway trips?

When I lived on a culdesac, my ex-wife used to wear the edges of her van tires at an alarming rate. Paticularly the passenger side front, outside edge. She ran lots of erends and short trips... many u-turns at the end of the culdesac was the cause.

[some_other_dave]

If you're going around corners "briskly", the wear is expected. I tend to wear out the outside shoulders of the tires on my "fun car" first...

If there's significant positive camber, you may also see that sort of wear. Particularly if it's in conjunction with a lot of toe angle. I'm not sure if it's toe-in or toe-out that does the job on the outer shoulder; I know that negative camber and toe-out will tear up the inner shoulder of the tire pretty quickly.

-soD

[MazdaMatt]

Check your toe settings. I believe toe-out causes outside wear, i might be wrong... if you don't want to spring for an alignment shop, google "string box alignment". Or, just put a measuring tape across the car from the outside of the tires on their front and back and see if the numbers match.

[trebuchet03]

Originally Posted by metromizer

You mentioned just moving... maybe your driving habits have changed somewhat, more in-town driving (where sharper turns eat the outside tires edges) versus longer highway trips?

Still mostly in town driving - but my neighborhood is different....

I'll change my route out of my neighborhood for the next few weeks and see what happens.

Check your toe settings.

That's a good idea - I'll do that a bit later

[Duffman]

Originally Posted by MazdaMatt

Check your toe settings. I believe toe-out causes outside wear, i might be wrong...

I would try camber. Even if your car is "within spec", a camber adjustment is in order to get the tire riding on the sweet center again.

[streeter]

If you are showing more wear on one front tire on the outer edge running tires that over inflated, then you have a toe problem with possible bad parts.
Outer edge wear on one tire is a sign of toe-in due to bad tierod or balljoint.

[trebuchet03]

I guess I should have been more clear, I see now that it's confusing...

If this is the tire's treads:

| | |

The outer two are the ones with extra wear. It's not just one side of the tire.

EDIT: Toe, as measured, was within spec.... Camber doesn't seem to be adjustable (based on a quick look) - I'll have to dig up my manual and check.

[TestDrive]

Take a look at the figure in Step 1 of this article.
The image in the first post of this forum thread may also be useful.

[bikin' Ed]

Too much toe in will cause the outside edge of a tire to wear abnormally fast. Too much positive camber will cause an area just inbound of the outside(usually the second rib) to wear abnormally fast.

I don't recall alignment adjustments for your car, but many FWD cars have no built in adjusters. For some of these cars there are shims made in the aftermarket to correct alignment. Before there were shims, we used to use a porta-power or hydraulic bottle jack to "coax" cars into alignment.

1/32 may not sound like much but it's probably about 10% of the usable tread!

My personal reccommendation is to get your car's alignment checked at either an alignment shop or a tire dealer. The guys working at these places usually know alot more about alignment wear than guys at a dealership--they're probably less expensive too.