- Ruler or Measuring Tape
- With the car parked on an even surface, hang a piece of tape from your fender. I normally stick a quarter at the end so that it hangs straight down.
- Measure in from the masking tape to the outside edge of your tire. This will tell you how much space you have until the tire will rub against the fender.
- I generally recommend picking a spacer that is slightly less than this measurement.