AWD tire mis-match

OK, so I know with AWD you should stick with same tires/rims all the way around, however I know people who have run slightly different combinations without any obvious ill effects, they just made sure the rears matched and the front matched.

Now I don't plan on going with different sized rims or anything drastic, I'm simply wondering if it would be ok, to run 2 different tires in the front and back. They would all be the same size, the front would match, and the rears would match.

Problem is, some prick that my mom teaches thought it would be funny to slash her sidewall after school. She has a Subaru, with some old Goodyear Eagles. The exact tire was stopped being made and I cannot for the life of me, find a replacement. She doesn't want to buy 4 new tires.

So can I run 2 Goodyears in the back, and 2 Sumitomos or something in the front, as long as they are all the same size, width, treadwall, etc.

The key to all this is rolling diameter.

As a general rule. most tire manufacturers closely follow the nominal dimensions as published by the tire standardizing organizations, and therefore, there will be minimal differences between tires of the same type.

BUT THERE ARE SOME THAT DON'T!!!!!

So the general rule is that tires on an AWD should be the same size, type, manufacturer and state of wear.

What these means is that there is a risk associated with deviating from this rule. The risk is driveline failure - and that can be expensive!

You can minimize the risk be careful selection of the tires - and what you're suggesting sounds reasonable.

But remember - IT'S A RISK!!

Hope this helps.

As a guy who replaced a transfer case in a Bravada because some goof drove it a few miles with the spare on with 3 different size tires I think you should be VERY careful with this. The comments about rolling diameter are right on. If everything doesn't turn at a 1 to 1 ratio something has to give that something is the clutches in the transfer case. When they are gone. there is no getting them back. Look at the Subaru site and search for Subaru specific data. The word on the GMC AWD is tire diameters as little as .100 different will kill the TC in short order. Good Luck.