Originally Posted by Mike Michaels
Anyone who says putting one new 10/32 tire on an AWD car with three 7/32 tires will cause issues is full of sh!t. Subaru included. You can get more than 3/32 from tire pressure variation alone - not to mention the temporary spare which I had to use for a week. With all the shimmy issues in this redesign one would be flirting with disaster to use a non-matching replacement tire. Neither dealer had an OEM replacement tire in stock. They don't even carry the OEM brand.
Youre right, that amount of variance can be done with tire pressure, that's why you should check them regularly.