When you look at the center of a wheel hub, the bored out center hole will tell you the exact vehicle type that the wheel will fit. If the center bore on the wheel hub is not an exact match to vehicle, the car can become uncontrollable when the vehicle reaches a certain high speed. Companies that produce the wheel hub often widen the center bore in order to fit a broader range of vehicles. The process to determine this bore size is simple and takes just minutes.
Place a wheel hub on a table or other flat type surface.
Place the end of the ruler with the number "0" (zero) on one side of the center bore of the hub.
Place one side of the combination square flat against the inner part of the center bore, making sure you are on the opposite sides of the ruler end with zero.
Take the reading of the numbers that are aligned the blade of the combination square along with the steel rule. The number you calculate will be the actual diameter of the bore on the wheel hub.
Take the measurement number you calculated in Step 4 and convert it from a fraction into a decimal number. Turn the calculator on and enter the non-whole number first. Now using division, divide the number on top of the fraction by the number on the bottom of the fraction to determine the value.
