HOW TO MEASURE YOUR BOLT PATTERN
4-LUG Measure center to center of two holes directly across from each other.
5-LUG Measure from the center on one hole to the BACK of the third hole.This is the easiest way to estimate a 5-lug bolt circle.
You can also measure from the CENTER of one hole to the CENTER of the third hole using 1.05 multiplier to find your bolt circle.
6-LUG Measure center to center of two holes directly across from each other.
8-LUG Measure center to center of two holes directly across from each other.
This info with drawings at:
http://www.mrt-wheels.com/boltpattern.html