Wheel Backspacing and Wheel offset

Follow the diagram below for a complete overview on how to measure wheel dimensions, as well as appropriate terminology for determining what size SUV, Jeep or truck wheels you want.

Wheel Width: Distance between inside of flanges rounded to nearest 1/2". Ensure that wheel width is proper for tire size you intend to mount on it. All tire sizes have minimum and maximum wheel width limits.
Wheel Diameter: Distance from bead seat to bead seat across diameter of wheel. Must be exactly the same as tire rim diameter. Always check diameter stamped on the wheel and match the tire exactly.
Wheel Offset: Distance between wheel mounting surface where bolted to hub of drum and centerline of rim. Determines vehicles “track” or distance between tires on each axle. Keep the wheel offsets as close to original as possible to avoid steering difficulties or wheel bearing fatigue.

How to Measure Wheel BackSpace

The easiest way to measure backspace is to lay the wheel face down onto the ground so the backside of the wheel is facing up. Take a straight edge and lay it diagonally across the inboard flange of the wheel. Take a tape measure and measure the distance from where the straight edge contacts the inboard flange to the hub mounting pad of the wheel. This measurement is backspace. The photo below shows three wheels with 2",3", & 4" backspace.

Items required to measure wheel backspace: