Q: Can I run different Size Tires front and rear on my Subaru Impreza WRX STi or Subaru Legacy SpecB.?
Do not run different Tire Sizes Front and Rear or Side to Side on a Street Driven Subaru. All 4 tires must match.
This includes all models of Impreza, Legacy, Forester, Tribeca, Outback, and Outback Sport with AWD.
Why you ask?
1.) Because Subaru Says so
2.) Because your owners manual says so
if you’re not sure, or don’t believe me go read it.
3.) Because saving $200 or even $500 today is not worth the expense or Hassle to fix your center diff.
On a more technical side of things,
You can’t run a different rolling diameter front and rear on a street driven Subaru due to its AWD system. The center diff will try and compensate for the differing speeds between the front and rear tires and proceed to overheat and eventually fail.
This also applies to running different Model tires of the same size. EVERY aspect of your 4 tires should match when installed on a Subaru including;
This is the only time that it makes sense to buy crappy tires for an STi.
Also proper rotation is key to the longevity of both your tires and your differentials, rotate your tires consistently and often (i.e. Oil changes/after autox’s/after track days).