Several websites provide guides for vehicle wheel bolt patterns, including BoltPatternSearch.com, DiscountedWheelWarehouse.com and RoadkillCustoms.com. The first two sites offer lists of vehicle names so that a user can quickly find a bolt pattern measurement for a particular vehicle. Some sites contain instructions about how to perform this measurement.
A bolt pattern measurement typically appears as two numbers separated by a dash. The first is the number of lug nuts that hold the wheel onto the car; the second is the diameter between the lug nuts. For wheels with an even number of lug nuts, determining this diameter is simply a matter of measuring from lug nut to lug nut across the center of the wheel. For wheels with odd numbers of lug nuts, the calculation is more complex, so using a bolt pattern gauge results in the most precise measurement.