Tire wear issue 94 850 T - common problem?

tomellis · Post by **tomellis** » 25 Oct 2007, 12:24

I have a 1994 850 Turbo wagon that I bought used from a friend 6 years ago with just under 100k. The car now has ~165k, and for the entire time I have owned the car the tire life has been horrible. The issue is always the same, excessive outer edge wear on the front tires. I have the car aligned regularly at Firestone (lifetime alignment deal) and also rotate the tires every 3-4k but it doesn't seem to make any difference. The techs at Firestone say the suspension/steering gear all looks good, and can't explain why this is happening. When I first bought the car it had brand new Michelin MXV tires; these lasted ~25k. Currently I'm using Kumho Solus, and after ~25k the outer edge of all 4 tires are almost bald. The inner 3/4 of the tires look great; if the overall tire wear was the same I'd get 50-60k from these tires. I am running 205 55 R16 H rated tires, so I'd expect better mileage than the softer V or Z rated tires recommended by Volvo.
Is this a common issue with this model? The car is driven pretty gently, so I can't blame the wear on aggressive driving/cornering. Has anyone else had this problem, and if so did you find a way to fix it?

Post by **Ozark Lee** » 25 Oct 2007, 13:30

I would be curious to see your alignment printouts. My guess is that they are not doing anything about camber. As shipped from the factory your car does not have a camber adjustment capability. There are aftermarket "camber kits" which will allow the camber to be adjusted. They are not very expensive as they are just a modified nut and bolt.

Here is a link to the Eibach version:

http://www.autocarparts.com/part/276/721/

I think Ingalls makes them as well.

Also, make sure that the Firestone guys are aligning the rear wheels, most cars don't have rear wheel alignment capability but ours do have adjustable rear toe in.
...Lee

tomellis · Post by **tomellis** » 25 Oct 2007, 16:06

Hi Lee, if you tell me what might be helpful I'd be glad to post the specs from the alignment I had done earlier today. Is there anything in particular that might help or should I just put up everything?

Firestone is aligning both the front and the rear wheels, and I haven't noticed any unusual wear on the tires when they are mounted in the rear. Only in front, and only on the outside edges. To me that sounds like a toe problem (though I'm certainly no expert), but the numbers for toe-in when the car is aligned are within factory specs.

Post by **MadeInJapan** » 25 Oct 2007, 17:06

Tie rod ends (if only happening on the outer fronts). Everything could be in spec but the tie rods could be worn just enough for the alignment people not to notice but still affect your tire wear. OR Firestone could be aligning with the wrong specs and have the toes inward. The leading edge always loses rubber.

tomellis · Post by **tomellis** » 25 Oct 2007, 17:35

I had the wheels aligned this morning, and after talking to the folks at Firestone decided that I'd probably get better information from this forum! I looked at the numbers for camber on the front. the left side (which seems to wear less) is at -.32", while the right (worse wear) is at -.13". The acceptable range according to Volvo is -1.00" to +1.00". Do you think the difference between -.13 and -.32 could be enough to explain the wear? Perhaps both wheels should have the camber adjusted further to the negative, to -.4 or -.5? Lee mentioned an aftermarket kits from Eibach that allows easy adjustment of camber, which I understand is not adjustable on a stock 850.
The toe is currently set at .15" on both sides; the specified range is .12 to .22. I don't know how toe numbers work, but could the wheels be toed in too far? Would more toe-in be a higher or lower number?
I think I replaced the tie-rod ends a couple of years ago, but I need to look at my records to check.
Thanks for your help! Tom

Post by **MadeInJapan** » 25 Oct 2007, 17:58

I just checked and their specs seem correct. Here is what's in the downloadable manual (make sure degree specs are measured in degrees and inch specifics are in inches):

The number is the middle is the Preferred spec.
Camber (1)
Front .................. 0 ................... -1 To 1
Rear ................. -1.0 .............. -1.5 To -.5
Caster (1) ............. 3.33 ............. 2.33 To 4.33
Toe-In (2)
Front ................. .16 ............... .11 To .21
Rear .................. .03 .............. -.05 To .12
Toe-In (1)
Front ................. .33 ............... .23 To .43
Rear .................. .07 .............. -.10 To .23
(1) - Measurement in degrees.
(2) - Measurement in inches.

cyclmck · Post by **cyclmck** » 26 Oct 2007, 18:54

Only too low of a tire pressure, incorrect caster, or aggressive cornering can cause excessive wear on both outer edges of the front tires. Maybe the wear is not that excessive though. How often are you rotating the tires?

tomellis · Post by **tomellis** » 26 Oct 2007, 20:20

I rotate the tires every 3-4k. Due to the rotations all 4 tires now have noticeably higher wear on the outside edges. I keep the tire pressure at 36 psi. The caster is currently at 3.22 on the left front, and 3.89 on the right front; according to the Firestone people the specified range is 2.33 to 4.33. I thought that caster was front/back position of the wheels; it would seem to me that incorrect camber would be a more likely suspect, though I've learned that with cars what seems to be a logical assumption can get you into trouble. Since the camber is also well within the specified range the fact that the front tires are wearing so unevenly makes even less sense to me.
I'm hoping to get a look at the suspension this weekend to see if anything is obviously worn, but I'd think that the Firestone boys would normally check for wear in the hope of getting some business if they found parts in need of replacement. I told them that I was unhappy about the uneven wear before they did the latest alignment, so I would guess that they looked for some problem that they could charge me to correct!

cyclmck · Post by **cyclmck** » 26 Oct 2007, 23:06

tomellis wrote:I rotate the tires every 3-4k. Due to the rotations all 4 tires now have noticeably higher wear on the outside edges. I keep the tire pressure at 36 psi. The caster is currently at 3.22 on the left front, and 3.89 on the right front; according to the Firestone people the specified range is 2.33 to 4.33. I thought that caster was front/back position of the wheels; it would seem to me that incorrect camber would be a more likely suspect, though I've learned that with cars what seems to be a logical assumption can get you into trouble. Since the camber is also well within the specified range the fact that the front tires are wearing so unevenly makes even less sense to me.
I'm hoping to get a look at the suspension this weekend to see if anything is obviously worn, but I'd think that the Firestone boys would normally check for wear in the hope of getting some business if they found parts in need of replacement. I told them that I was unhappy about the uneven wear before they did the latest alignment, so I would guess that they looked for some problem that they could charge me to correct!

The camber being off would cause excess wear on one edge of the tire(positive camber causes more wear on the outside and negative camber causes more wear on the inside, but the camber being off could not cause both edges to wear excessively.) Caster is the steering axis angle(picture the top of the strut being moved forward or back), if the caster is off, when you turn either way, the wheels tilt over more than they should, so both edges can wear excesively. Your tire pressure sounds good. And you are defintely rotating the tires often enough. Maybe bad strut mounts or ball joints? but you would probably notice the loose feel of that.

tomellis · Post by **tomellis** » 27 Oct 2007, 00:10

After reading your answer I'm afraid that maybe I haven't made my problem as clear as I might have. When I say the tires are wearing on the outside edge, I mean just the one true "outside" edge of each tire; the right front tire shows excessive wear on the right edge, and the left excessive wear on the left edge. If you looked at the tires and didn't see the outside 1/8 of the tire you would think the tires still had >50% tread. I'm going to try to take some photos of the current two front tires in the next day or so (I work weekends so it may not happen too quickly) and get the photos online so everyone can see just what I mean. I apologize if my earlier description wasn't accurate enough to make a diagnosis easier!