Accurate measurements are essential to finding the right wheel for your application. Here’s how we take the most common wheel measurements.
1. How do I measure backspace?
Place the wheel (without tire) on a flat surface, face UP.
Put a ruler down through the center hub hole.
The distance from the flat surface to the bottom side of the center is the wheel backspacing.
2. What is offset?
Offset and backspacing are two terms commonly used in wheel measurement that can be
confusing at times. Advertised wheel width is generally measured at the inside tire bead mounting
surface, but you must determine the overall wheel width from the front to rear lip – usually 1-inch
total. So a wheel that is advertised as 15×8 is 15-inches in diameter, 8-inches from tire bead to
tire bead but 9-inches wide overall.
Offset is the distance from the mounting pad to the centerline of the wheel. Offset can be positive
(more backspacing) or negative (less backspacing).
Backspacing is the measurement from the mounting pad to the inner edge of the wheel.
To order Circle Racing Wheels, you’ll need to measure backspacing, not offset.
3. How do I determine my bolt pattern?