I have a set of wheels 18x8.5 and 18x9.5 both with a 20mm offset. I put just the wheels on the back to see how they looked and it appeared that the rim stuck out a fair bit from the wheel well. Are these the wrong offset ? (car is not lowered. Will they rub?) Tires will be 275/40 on back and 245/40 on front.

 

They are not wrong... I would say that are a little agressive... This basically means you have to camber them in... Depending on what brand tires you have I think you will be OK... Hope that helps...

Oh yeah Volk GTS are 17mm & 18mm offsets...

 

I have the +17/+18 GTS and the back barely sticks out a hair. I would think +20 would be closer in. But then again I've never seen a +20, only +22.

 

You should be just fine. People run lower offsets than that with a 10.5 in the back.

 

loweer your car...they will sit very nicely

rear fender rolling may be necessary, depends on the tire

 

There is no right or wrong offset. Are you clearing the rotors and strut towers? Is the fender cutting the tire? If no than they are the right offset.