I've had my front end aligned twice within the last year and my front tires are excessively wearing on the outer edges. (meaning both edges per tire) Can strut problems cause this? To the best of my knowledge the car was never wrecked & has no frame damage. Any suggestions? (1999 A6 Quattro, 2.8)

 

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Both edges get worn on the same tire, you say?
- That an obvious sign of driving on underinflated tires.

If only one edge would have gotten worn out, then you should start giving some thought about re-checking the toe alignment, or inspect bushings, joints, etc.
Also, is your steering wheel off-center as well? It may not even be out of question a check of the "thrust angle". Even if you had 2 front end alignments within the year, a rear axle misalignment can affect the toe angles.

However, "both edges per tire" getting worn out point out to underinflation.

 

I had some un-even wear on one side per tire and some vibration issues. I had to replace upper and lower bushings, and so far so good.

Both sides on each tire wearing is odd however. Have the tires been changed from oem size and you are still putting in the pressure of the old tire size?

 

My assumption is that you should always go by the tire manufacturer's recommended psi, regardless of the fact that is an OE or other size tire, or despite what it says in the vehicle's owner manual.

If the new tire's specs list 35 PSI, yet the pressure for the stock tires is listed as 33, you should go with the tire manufacturer's recommendation for that particular tire. Underinflation not only ruins the bead retention during cornering, but it may turn dangerous from a safety perspective. Laslty, underinflation it also changes the gas mileage because of more resistance to rotation.

 

I agree INDER-INFLATION or the tires are too wide for the rims.

If it was misalignment -even if caused by worn parts - the tires would wear unevenly. It sounds like the alignment is OK because the wear is even. That leaves inflation.

Too much air and they wear in the center - too little and they wear on the edges.

 

Tire air pressure is right on, no under inflation here! Wouldn't "even" tire wear be the entire tread of the tire wearing equally? This is just both outer edges of the tire. The center & most of the tread is fine. The edges are now bald and will probably start showing the core ribs by spring. One thing I noticed is that the left side makes a slight clunk sound if I hit a sharp bump. That's why I was thinking maybe it's all a strut issue. But both front tires have the problem so maybe the sound on the left is a whole other problem not related to this. I was hoping someone would read this and say "Oh, that recently happened to me too, here's what needs to be done..." Thanks for the suggestions & if any other ideas on the cause of this come to mind, please don't hesitate to post.

 

You may be right, as you probably have an entire different problem than just the air pressure.
I speak from my own perspective at least, but both edges worn out on the same tire can be caused only by underinflation, or (as NH pointed out) by unfitted tires for the rims. There's no way you will have both edges worn out if it was a misalignment problem. Either too much positive or negative toe, the tire should have only one edge worn out. Even if cornering hard to both directions (as a possible explanation for both edges being almost bald), that toe out/in difference will still cause different wear rate of the two edges because of the wheel's angle in relation to the road.

Good luck finding what the problems is , and please do share with us.

 

Only bias ply tires have the "underinflation wears the edges, overinflation wears the center" problem. Radials just heat up more and wear out faster all around. Wear on both outside edges = worn suspension arms (or cornering too fast). The clunk points in this direction as well. Worn shocks will cause scalloping of the edges.

Bob

 

the inside and outside edge of each tire wearing, without any feathering of the tread pattern, is underinflation. plain and simple.

any suspension/bushing/bearing problems would cause a camber and/or toe issue. camber would be a wear on a single edge without feathering. toe would show wear on a single edge with feathering, cupping ect ect.

to answer the question of another, the tire pressures are close to OEM for aftermarket tires. the OEM pressures are listed inside the drivers door jam. i run 225/40r18 and the backs on my 2000 a6 mt6 wear nice and even @ 34-35 cold psi. however, 36 cold psi is too low on the fronts. i have a rub issue causing my tire to wear on the inside, but i plan the run 38psi/34psi cold nitrogen on the set of toyos i am getting tomorrow. i just hope they can find where it's running before i tear up another set of tires.

i was just searching the boards for what other people were running for psi when i found this thread.

 

I am running 38/35 on both cars.
The Elantra has 2 Cooper Lifeliners on the rear with 40,000 miles on them and still have 45-50% tread left. Some while back my wife had a bad flat which destroyed the tire and bent the rim slightly (it turned it into a full spare), so I had to purchase two new tires. Got two Hankooks for the front, which are going on 10,000 miles and you can still see the beading.

On the Audi I just put 300 miles back a new set of Contis on. I purchased the car with bad toe-in wear, but I did adjust the tie rods last week when finishing with the CV axles and hubs/bearings. Will see if that was the only problem or maybe I need new struts or control arms.
Anyway, 38/35 worked for me great over the years on pretty much all the cars we had.