When measuring even numbered lug stud spacing you go center to center of opposite studs
When measuring odd numbered lug studs you measure the outside of one stud to the center of the most opposite
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The results are approximate not exact.
If you measure a 5x4 vs a 5x5.4 you will have 2 specific different nunbers, one will be close to 4 one will be close to 4.5. but neither will be exactly 4 or 4.5.
