I dont know about the issues the other guys have stated.

Wheel spacers can be very dangerous, unless you spend some cash and get the hub adapter spacers.

The way our cars are setup they have a "hub-centric' ring that the rim rests on. With a spacer you lose that. The lugs end up loosening up very quickly.

We have to run spacers on our swap drag car, and even at 110ft lbs the lugs loosen up EVERY pass.

HTH-Jeremiah

I ran spacers the smallest available they were like 5 or 6 mm and 225 65 16'* they rubbed on the outside of the fenders granted i think my rims have a bit much offset