BACKSPACING VS. OFFSET
Wheel Offset and backspace are essentially two different ways of looking at the same thing. They determine the location of the wheel and tire assembly when bolted to the vehicle hub and can make or break the look, performance and durability of your UTV/ATV.
Wheel Offset is the measured distance between the hub mounting surface and the wheels center line.
Wheel Backspacing is the measurement from the hub mounting surface to the back edge of the wheel.
Typically speaking, the higher the offset/backspace, the more the wheel will tuck inward towards the suspension or away from the fender. The lower the offset/backspace, the more the wheel will push out away from the suspension or towards the fender.
Here’s how to calculate the backspacing using the rim width and offset:
First – add 1″ to the rim width and then divide by 2 to find the wheels center line (you have to account for the wheel flange which is why you add 1″ to the rim width). Second – convert the offset which is in millimeters into inches (there is 25.4 mm in 1 inch so divide the offset by 25.4). Lastly – add the converted offset to the wheels center line (if the offset is positive) for the correct backspacing or subtract the converted offset to the wheels center line (if the offset is negative) for the correct backspacing.
Understanding how back spacing is measured and how it affects your vehicle is critical in the fitment of the wheel (and tire) to the vehicle. Since the suspension, brake, steering, and drive systems are typically located behind the wheel, the back spacing is used to define a volume behind the wheel where these items can exist.
Items required to measure wheel backspace:
- Tape measure
- Straight edge
- Wheel without tire (preferred)