I am looking at some rims for my 05 g35 coupe and i currently have the 18" performance wheel and tire package that has a +30mm offset. I am wanting to put on a set of wheels that have a +40mm offset. Can anyone tell me how much of a difference this is? Does 10mm really matter or is it so small that this is irrelavent? This means also that the wheel itself will be pushed out 10 mm from its current position correct? will it be too far out of the fenderwell?

 

Quite the opposite, actually. A wheel with a +40mm offset will sit further into the wheel-well than a wheel with a +30mm offset. The offset is the distance between the wheel mounting surface and the center line of the wheel. So, a larger offset, will push the mounting point further towards the outside of the wheel therefore creating more backspacing therefore moving the wheel further inside.

 

what he said, don't do a 40mm, you won't like the look even if they fit, 10mm can make a big diff