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.

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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.

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.

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.

A couple years ago I mounted summer Coopers on my 18" rims and experienced severe edge wear and three of the tires failed while driving. I had them all replaced by Discount under their "full coverage" tire insurance and then took a trip to SC and back. Upon my return I went in for a rotation and found them all worn to the cord on the inside tread. I also had the alignment checked before and during this fiasco, and it was within specification.

They were all replaced with Continentals and even though I only have 9k miles on them, no problems. I think some tires just don't do well with quattro.

This might give you a hint.

http://image58.webshots.com/558/7/95/23/2809795230047362070iwpNmJ_ph.jpg

You guys are all wrong about the under-inflation/tire pressure thing as being the cause of this problem! Bob Martin had it right, suspension. And he's right about pressure not affecting radials as much. So whoever said under-inflation or over-inflation plain & simple...guess again. There's way more to it! Suspension problems are difficult to pinpoint as the mechanic showed me. Not trying to battle anyone. I hope this can help other Audi owners with Quattro experiencing similar issues.

I think you actually should have battled the people who did your alignment TWICE, without checking all the suspension parts...
Is a typical Roseanne Roseannadanna situation: "Just like my father said: if is not one thing, is another"
Someone had to get it right.

Anyway, would have been nice to pinpoint what were the actual suspension problems...if you want to help other Audi owners.
Glad you found the solution to the nagging mystery.

So what was wrong?

Saxrasta,

As the original post was 8 months ago and it sounds like you have it fixed, what was wrong? (Like, what part(s) was bad? -- "Suspension" covers "LOTS" of parts!)

You guys are all wrong about the under-inflation/tire pressure thing as being the cause of this problem! Bob Martin had it right, suspension. And he's right about pressure not affecting radials as much. So whoever said under-inflation or over-inflation plain & simple...guess again. There's way more to it! Suspension problems are difficult to pinpoint as the mechanic showed me. Not trying to battle anyone. I hope this can help other Audi owners with Quattro experiencing similar issues.

well now i'm interested. while i'm not an ASE master mechanic, i have spend countless hours under a lift. i have yet to find a suspension problem that will wear the BOTH edges of the tread and not the middle of the tread and have no feathering or cupping. what suspension ailment could cause such an event? i know, for a fact, that on radial tires, under inflation WILL, for a FACT, wear the edges of the tread and not the middle.

As I mentioned before, my tires have always been kept at proper inflation. That alone takes away tire air pressure as the cause. There is no simple single thing that causes this wear. My problem isn't fully solved, but I've had some of the rubber bushings (not sure of proper terminology on these pieces) replaced. Also had one of the lower suspension arms replaced. I'm wondering if I need new strut inserts. Car is almost 11 years old with 126k miles. They had to use a pry bar to show the play where the rubber pieces were worn. Currently using V rated Dunlop SP sport tires.

I'm wondering about your wear, too. One thing you might check is the top strut mounts. The bonded rubber breaks loose from the bushing, wears it, and the whole alignment thing is out the window.

Had that on a 90 100. 2 shops aligned, after new tires put on. Car DID pull, and you don't mention that. Tires replaced under warranty, but prorated.

Found that the strut mounts were worn out, about 20 bucks each, install yourself. Tires wore forever after replacing them and re-alignment.

My experience, too, that underinflation will cause shoulders to wear while center of tread is perfect.

Question. New Pirellis on the front. About 10 thou on them. Wearing the right one down, at least twice the left, that one is like new. Back to the tire shop, complain. Got BS that "Oh, your right tire is the driving tire, they ALWAYS wear faster than the left."

It is a Quattro, all 4 wheels drive, basically. They say you should rotate more often. I say I would have TWO tires that are half worn instead of one like new and one 2/3 worn out.

Regardless, MEBBE 20 thou on a pair of 760 rated tires.

I gotta write Pirelli about this. That's the only way I got replacement of the Coopers that wore out on my 90 100.

Cheers,

George

^^while your wear seems excessive, they are correct in that the right tires wear faster than the left. The right tires travel farther due to left turns :)

Hey George!!! Where have you been lately?
I just cooked some cevapcici tonight and was thinking about you :)
Good to see ya back.

You guys are all wrong about the under-inflation/tire pressure thing as being the cause of this problem! Bob Martin had it right, suspension. And he's right about pressure not affecting radials as much. So whoever said under-inflation or over-inflation plain & simple...guess again. There's way more to it! Suspension problems are difficult to pinpoint as the mechanic showed me. Not trying to battle anyone. I hope this can help other Audi owners with Quattro experiencing similar issues.

It was not a guess!! I have lots of experience with with both radials and bias ply tires on the street and races tracks.

Radials do wear on the edges (both) if underinflated, but not as much as the older bias ply tires. If the wear was only the outside (or inside) edges of the front tires then the prob would be alignment. Most likely toe out if both tires show the same wear but it could be camber.

One would expect that any competent mechanic would make sure the suspension was OK before doing an alignment. It's not rocket science! The mechanic that told you that suspension problems are "difficult" to pinpoint needs to get some schooling. Problems like yours are usually not found because the mechanic lacks knowledge or is too lazy to do the job right.

Actually my mechanic specializes in imports such as Audi, Mercedes, VW, etc. He even showed me what he was talking about. These problems aren't shown by loose wobbly wheels with the car up on the rack. He had to really pry to show the play. I think the unibody frame may have somehow bent slightly, and I think the struts are a contributing factor.
Again, not trying to get into arguments here, but when I tell you tire inflation isn't the issue, you can be sure I know that for a fact. I do a lot of my own upkeep work like oil changes, brake pads & rotors, spark plugs, other filters & fluids. I don't have the facilities to go much beyond that. But I definitely have a good general understanding of cars and can identify most common problems.

Chefro,

My cousin goes crazy about cevapcici. Goes to Florida, a store down there makes them for sale, she fills a cooler with them and brings them home. Recipe I read says they're basically rolled out ground beef mix.

I'd rather have gra i kupus.

Midnight,

Damn. Now that tire is on the left. I was gonna make more right turns to even out. Guess that'll just wear that one out even faster.

So much for Pirellis. Tried Coopers. Maybe some Contis next time. Don't THINK I am gonna buy Hankook.

Cheers,

George