Even Lug Bolt Patterns (4 Lug, 6 Lug, 8 Lug)
Measuring is very straightforward. Simply measure from the center of one stud to the center of another stud directly across, like from 6 o'clock to 12 o'clock.
Odd Lug Bolt Patterns (3 Lug, 5 Lug, 7 Lug)
Odd number lug patterns can be a bit tricky. The correct way to measure a 5 lug bolt pattern is to measure from the center of the first stud to the OUTER edge of the third stud. Please refer to the diagram above as a visual aid.
NOTE: DO NOT use the 4 Lug or 6 Lug measurement method for 5 Lug bolt patterns!
The same concepts will apply to measuring bolt patterns on wheel holes.