Tires affecting awd system?

[TGX4776]

So I was told earlier that all 4 tires need to be the same and have the same tread depth or it will screw up the AWD system? So even if its the same tires but the tires on the front are new and the ones on the back have about 14k miles on them will it affect the system?


I will also mention that it seems that only the front right tire is experiencing excessive wear on the outside of the tread. Any ideas on what that is?

[mike-tracy]

I'd recommend a complete alignment first of all. As for the tread difference, check your owners manual, but my 1996 Legacy manual says tires need to be within 2/32nd's of each other - otherwise the center diff will constantly be trying to correct the "imbalance," and will overheat and fail in the long run.

[Okin DaVanh]

S

I will also mention that it seems that only the front right tire is experiencing excessive wear on the outside of the tread. Any ideas on what that is?



Possible poor alignment, bad tie rod, bad wheel bearing, or even a twisted strut tower (tho very very rare) could be the culprit.


I'd check 1 & 2. Those are the most common.

[TGX4776]

Ok both of these are good to know. Tie rods aren't that expensive right?

[rougeben83]

about $30/ea, maybe less if you don't go through the dealer. rockauto.com is a good source.

Yes, subaru recommends less than 1/4" CIRCUMFERENCE difference between tires, that translates to about 1/32nd tread depth difference between tires. Reason is the center diff may sense the different wheel speeds as slip and be constantly shifter power to one side, eventually leading to premature failure.

[TGX4776]

I just talked to the guy I am buying it from and he said he just replaced the tie rod. So it's just an alignment issue I am guessing/hoping as he didn't get it aligned afterwards which could explain why it's only that tire. I'll get the mechanic to check out the circumference and see if it will be an issue.