Tire Size Difference... too much?

[mikeamondo]

So our son got a flat in our '99 AWD Legacy wagon, 2.2L auto, and the tire could not be repaired. Sears had the exact tire in stock, and changed it out free under the Road Hazzard warranty. The other three tires measure 9 out of 11 on their tread depth gauge...

 

Is that too much difference? Will it cause the tranny issues you get with different sized tires? Can't imagine a flat tire costing $400.... you know, if I have to replace all four!

 

Maybe someone should offer a 'tire wear down' service, to remove the right amount of the new tire in this situation... Maybe a machine that spins the tire against a giant wire brush.....

 

Thanks!

Mike

[StructEngineer]

Actually tirerack does shave tires for this exact reason. I dont know the specs offhand, but it sounds like too big of a difference in circumference.

 

This is the price you pay for AWD. Didn't the car dealer salesman tell you that when you bought it? haha

[idosubaru]

measured out it's probably over the Subaru limits. i'd probably risk it too...but i don't mind repairing it if something does happen and would probably rotate tires in such a way that the new one stays up front for awhile. put less air in it than the other side. considering how often tires loose air, i'm sure there's enormous amounts of "mismatched" tires out there for long periods of time, so doesn't scare me too much.

[johnceggleston]

The other three tires measure 9 out of 11 on their tread depth gauge...

 

Is that too much difference?

 

if my math is correct, the difference of 2/32 on a 185/70/14 tire is 0.19 inches which is within the 1/4" tolerance.

 

but this math is theoretical. to be sure you need to measure the actual tires.

 

i'd probably risk it if it is close. and keep the ''new'' tire on the front when you rotate until it wears down a little. (a year?)

 

or if the actual tires do not fall into the 1/4" allowance, buy a second new tire and run the new tires on the left and the old tires on the right.

 

or if it is an auto trans, put in the FWD fuse and keep the ''new'' 2 on the front for a year. this is not ideal, you run the risk of damaging the duty c.

Edited December 14, 2010 by johnceggleston