- Determine the wheel backspace: Lay the wheel face down and put a straight edge across the inboard flange. Measure the distance from the rule to the hub mounting pad in inches. Your result is the wheel backspace.
- Measure the width of the rim: Measure from the outboard flange to the inboard flange. Write your answer in inches.
- Calculate the center line: Take the width of your rim and divide by two.
- Subtract the center line from the backspace: For ex. If the center line was two inches and the backspace was 1 inch the offset would be positive one inch.Conversely, if your center line is greater than your backspace you will have a negative offset.
After calculating your current wheel offset, use this neat tool from 1010tires to see if your new wheel will have fitting issues.