Wheel Offset Calculator
Enter the current and new tire width and offset to calculate the offset and change to the inner clearance and outer position.
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Joe is the creator of Inch Calculator and has over 20 years of experience in engineering and construction. He holds several degrees and certifications.
How to Calculate Wheel Offset Changes
When changing the size of the wheel or when using a wheel with a different offset, the clearance on the inside of the wheel will change. When you change the offset, the wheel’s position will move closer or further from the vehicle, which can cause issues with clearance, such as rubbing or scrubbing.
A positive offset will move the wheel closer to the vehicle and a negative offset will move the wheel further out.
How to Calculate the Inner Clearance Change
When changing offsets, you can use the following formulas to calculate how much the inner clearance will change with the new wheel.
Start by finding the distance between the inner edge of the wheel and the hub mount for each wheel:
inner distance from hub mount = (width ÷ 2) + offset
Then calculate the change of the inner clearance by subtracting the inner distance from the hub mount for the new wheel from the current wheel:
inner clearance change = current – new
Often the wheel width will be measured in inches, but the offset is measured in millimeters. Ensure that all of the dimensions in the formulas are in millimeters. Try using our inches to millimeter converter to quickly convert between them.
How to Calculate the Outer Wheel Position Change
The outer position of the wheel will also change if the width or offset of the new wheel changes. Use the following formulas to find the change to the outer position of the wheel.
Start by finding the distance between the outer edge of the wheel and the hub mount:
outer distance from hub mount = (width ÷ 2) – offset
To calculate the change of the outer position, subtract the outer distance from the hub mount for the new wheel from the current wheel:
outer position change = current – new
When changing the size of the wheels on a vehicle, there will be a certain amount of error in the speedometer; you can measure this using our speedometer error calculator.
You might also be interested in our tire size calculator to calculate the size of new tires and compare with your current set.