There are four important measurements that are used to categorize and identify a wheel for fitment purpose. These are:

• Rim Diameter

  This is the actual diameter of the wheel at the point where the tire bead seats (not the outer lip).

• Rim Width

  Measure this from the inside of the outer lip at the bead seating point to the inner lip.

• Backspacing

  A very important measurement is from the inside of the wheel at the point where it contacts the hub, brake drum or axle flange to the outside edge (lip) of the wheel.

• Bolt Pattern

  Count the number of mounting holes for the wheel and determine the diameter of a circle that would run through their center. On a 4, 6 or 8-lug wheel it’s a direct measurement. On a 5-lug wheel, you can measure from the center of one hole to the OUTER edge of the hole diagonally across from it and get an approximate number that’s very close to the bolt circle diameter.