odd tire wear ... what will cause this?

[affende]

History / back story....

Vehicle: 1993 525I (stock suspension, non-sport suspension)

Tire: Sumitomo HTR AS P01

Size: 205 / 60 / 15

Age of tire: 24 months

rotation interval: 6 months

Time of ownership of vehicle: ~4 years

Yearly mileage: ~ 25,000 miles

Recently replaced the dog bones in the rear. Both were 100% worn (spherical joint would literally 'bounce' around in the housing). Rear swar bar has been re-attached to the car. both mounts were torn free from the car. I do not know how long the dog bones have been bad. i do not know how long the sway bar has been disconnected from the car.

Logically, however, the damage on those components were uniform from left to right. Although it will contribute to abnormal wear / odd wear ... being uniform damage i would think there would be uniform wear. i.e. both dog bones being bad and no sway bar .... affecting only the right rear tire? I think not. However i could be wrong.

The tire is question is the right rear tire. The left rear has normal even wear around the circumference.


The first picture is of the left rear tire for comparison.





Here is the bad tire ... Right rear.

Best portion of the tire.




Worst portion of the tire ... approximately 120* from the worst spot to the best spot ... i.e. the two extremes are not 180* apart




Tread depth at water channel ... best side of the tire.




Tread depth at water channel ... best side of the tire.



Tread depth at water channel ... best side of the tire.


Tread depth at water channel ... best side of the tire.


Wear bars, worst side of tire


wear bars, best side of tire.


wear bars worst side of tire.











Before i removed the wheel, i check for lateral runout with the good old spin the tire and watch it. I could not see any runout. but im blind in one eye and i cant see out of the other one.

It seems like there is some lateral oscillation with the rotation of the tire. I could not find the culprit.

any ideas from the tire gods?

im going to get my alignment checked right now. ill report back with alignment print outs.

stupid tire video

[mryakan]

any rubbing?

[affende]

any rubbing?

no rubbing whatsoever.

also, i left out from the first post.

mileage on the chassis: 209,000 miles.

shop was packed .... alignment will be done Wednesday.

[jamonlee]

for sure its your alignment

[locknload]

Had this same pattern on the front tires of my E38; coincidentally, I also have the same sumitomo tires as you, but that is not a factor here. On my car the toe was bad due to a bad idler arm bushing. You don't have that on the rear, but this is definitely a toe problem. The sway bar is probably not a contributor as it has nothing to do with the alignment. It is only there to move the opposite side of the suspension in relation to the other to keep the car more level in a turn. I presume the dogbones you are talking about are the pitman arms and not the sway bar links? They look similar, but as noted, any repairs to the sway bar wil have little effect on the alignment. If the pitman arms were replaced, you most definitely should have the alignment checked. Highly probable you have other issues going on back there (worn bushings, etc) that can be diagnosed on the alignment rack.

[affende]

correct ... the pitman arms were replaced. (as were the sway bar end links ... but that shouldnt cause or fix this problem.

im thinking shocks could contribute .... but i agree this looks a lot like a toe problem. in which case ... ill be blowing up my car.

the alignment will be done wednesday.

[lambopilot]

alignment, and seperated tire, thats why it is severely worn in one spot.

the tire likely seperated due to excess heat caused by the misalignment.

[affende]

Update on this thread. had the car aligned, along with the replaced pitman arms, and have had zero issues since.

[TostitoBandito]

I know this is an old thread, but for anyone else's benefit that is what a tire looks like when you're running WAY too much camber+toe. The inner shoulder is completely worn down to nothing because it's being dragged across the pavement at an extreme angle.

In this guy's case, I think it's safe to say something was broken or way out of alignment in the right rear that caused this. The ball joints must've been basically falling off or broken to allow the tire to camber out or toe in/out enough to do that. The difference from left to right should've been visible just standing behind the car and eyeballing the tire angles.

[JBasham]

It will also happen on a track car, properly aligned, with soft tires and an open differential.

[Jim@tirerack]

Yes it is alignment. Tires are stupid so they are only going to do what the car tells them to do. Tires will roll straight and wear evenly if everything is correct on the car. Unfortunately when the wear is on the inside you don't notice it till it is too late.

[asphalt4463]

When I was into GTI's, I used to set the front's to toe-out. The inside edge would scrub just like in your picture. The tires wouldn't last quite as long but it was a small compromise as I felt that I got less understeer and the turn-in was better with the spring/strut/sway bar combination I had. Check your specific cars alignment spec or at least set toe to zero and your tires will wear evenly.