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Subaru Tire Size Outback Sedan versus Legacy GT Spec B

Help. Does anyone have any experience on tire sizes? I have an 06 Outback Sedan and want to purchase the rims from a Legacy GT Spec B. The Outback requires a P225/55R17 and the Wheels from the Spec B are P215/45R18 would this make a difference? The only information I’ve been able to get is that the 18 inch wheels need to be P215 because of the fit? Suggestions or comments welcome. Thank you in advance David.

The Spec B tires will be 1.13 inches shorter in terms of height. This will change your overall gear ratios a bit, causing slightly improved acceleration, with a corresponding increase in RPM in highway driving. The tire will also be slightly narrower, possibly reducing on-road traction. Personally, I don’t see many upsides to this; you won’t gain anything really notable other than looks, since the stock tires will likely provide better traction.

Post or search on this board in the tires & wheels section. Probably someone has done it.

I can’t tell you if the rims will fit, but there is an issue with the tire sizing:

The Outback tire size is P225/55R17 95V (note the service description) mounted on 7" rims inflated to 32 psi front / 30 psi rear, while the Legacy is P215/45R18 89Y mounted on 7" rims inflated to 35 psi front / 33 psi rear. The Outback has a slightly larger load carrying capacity than the Legacy (sort of makes sense).

So if you are considering using the 18" rims from the Legacy on an Outback, you’ll need to use a tire with a 95 Load Index that fits a 7" rim and fits in the fenderwells. The problem here is that to be sure there is enough clearance, you have to measure everything inside the fenderwells. The folks that do that sort of thing think it gives them a competitive advamtage (probably true!), so they don’t share.

I suggest you contact Discount Tire or Tire Rack. They both do those sorts of measurements

Good day…Thank you that helps a lot. Actually I do just like the looks and that is my only motivation. I’ve only got 13,000 miles on the car and rarely drive it. When I contacted Subaru they just said put the recommended size on and that was it. I guess I should leave well enough alone and just be happy with the wheels I’ve got. Thank you again! David

Thanks for the info I’d forgotten the tire pressure differences! I had a guy I know from Bridgestone give me a formula for my WRX and you’ve both given me a lot to think about. I really just like the wheel for looks more than anything…I will try Tire Rack and also the other website… Thanks again. I appreciate you taking the time to respond. David :slight_smile: