I'm looking into some new wheels for my '01 Impreza Outback Sport and I have no clue what a 48mm offset is? I've been looking at Rota Tarmacs which come in 17" and 18" and am not sure if both sizes would fit my car. Thanks

 

From the diagram you can see that "offset" is the distance from the centerline of the rim to the hub mating surface at the center of the rim. A higher offset moves the rim towards the car (further into the wheels well), and a lower offset moves the rim away from the car. If you have rubbing issues on the inner side of the tire then you'll need a lower offset rim or wheel spacers.

 

 

hope that helps:D

 

edit: mixed up stuff earlier, thanks vrg3

Thanks man, that was very helpful. Where might I find some wheel spacers?

no prob:)

 

You should be able to get the wheel spacers from the same place you are getting your rims, just ask them about the spacers.

Does changing the offset significantly change the load on the bearings?

I wouldn't worry about anything +/- 5mm but beyond that the bearings WILL see increased wear due to an offset load. Our cars already have picky bearings so try keeping an offset as cloe to stock as possible.

Agree fully on the max 5mm tolerance. Make sure the total diameter will fit inside the wheel well and clear the lower spring dish on the struts, the tolerance here is quite narrow from stock.

Originally posted by Nuwan

A higher offset moves the rim away from the car, and a lower offset moves the rim closer to the car (or further into the wheel well). If you have rubbing issues on the inner side of the tire then you'll need a higher offset rim or wheel spacers.

 

Wait a minute -- I don't think that's right. A higher offset moves the rim further into the wheel well. Look at the diagram; it should make that clear. A higher offset puts the centerline of the wheel further away from the mounting surface.

 

Spacers decrease offset.

 

That's what made it hard to find rims in the US for Subarus before WRX-mania. Subarus use a very high offset, and there isn't a good way to adapt a low-offset wheel.

whoops, i mixed things up by accident, thanks for catching that vrg3:)