So I just purchased a new set of wheels for my .1 Turbo which I have equipped with GMG springs. What tire size would be ideal for a 20x9 +42 front and 20x12 +55 rear? I would like to run atleast a 325 section rear. Would a 255 30 fit on the front?

 

245/30R20 and 325/25R20

255 front is too big for a 325 rear

 

I guess I should clarify. Will it fit under the fender? I am trying to stay away from a stretched tire as much as possible.

Also, why would a 255 be too big for a 325 rear?

 

245 should fit under your fender, it does on mine. I don't remember the offset, but they're semi aggressive with 10mm spacers, and over 2* negative camber.

If the tire width ratio is not the same at stock, people say it can cause premature wear and failure of the front diff. That's what "they say"... I don't want to be the one to test that theory though.

 

Double and triple check all your calculations when you do non-standard wheel/tire sizes. If the front-back difference is greater than 3% you accelerate wear on the differential which is several grand to fix.

 

255/30/20 vs 325/25/20 looks like it will be 1.2% difference in diameter from front to back. Please correct me if I am wrong. It also keeps the front to back ratio the same as stock.

So my only question is the front width + offset with the 255 section tire.