When a wheel comes with a +40mm offset, like the Slipstreams, what exactly is that number in reference to? How will that number have an effect on fender rub, handling, and anything else? Thanks....

 

http://tirerack.com/wheels/tech/offset.htm

 

So basically offset has nothing to do with your wheels rubbing your fender? Its all in the diameter and width of your tires? I want to dump my coupe a little bit more, but the 17's i have on it right now rub my fender when I turn and hit tiny bumps.

 

It depends on where they rub. If they rub on the fender, then you want to increase the + offset. When doing this, you have to be careful to ensure that you won't rub on the inner fender, suspension, or body.

 

If the offset is higher, it pulls the wheel/tire farther inward. If it is lower, or negative, it pushes it farther outward.

Think about slicing a wheel in half, right down the centerline, so you would have an inner rim half, and the outer half w/ the spokes, lug holes, etc. Now place a straightedge across that cut edge on the outer wheel half. Then measure from the straightedge to the flat surface inside the wheel that contacts the hub on the car. That measurement (usually in mm) is the offset (positive offset in this case, as it is with pretty much all FWD cars). If you were stick a spacer in between the wheel and the hub, then the effective offset becomes less, and the wheel is pushed outward. HTH

 

Gotcha I have 17x7 +40mm offset wheels right now that have caused some damage to my fender from going over bumps or cornering hard. If I got some 16x7 or 15x6.5 (+40mm offset) Rotas do you think the problem would be solved? Or should I go with the 16x7 +45mm offset Slipstreams just to be sure?

 

go with the 15's with a 40 offset i have a set of rota with that offset works find doesnt rub i drop my car low too.