Diameter-matched size
Solves the aspect ratio that holds overall diameter constant on the new rim.
Plus sizing
Plus-size a wheel without changing diameter.
Enter your current size and a new rim diameter to find the tire that keeps overall height the same.
What it does
How this tool helps.
Calibration safe
Keeping diameter the same keeps the speedometer, odometer, and gearing accurate.
Real sizes only
Rounds the aspect ratio to a manufactured step and checks the result is a valid size.
Related tools and guides
Plus Size Tire Calculator FAQ.
Plus sizing moves to a larger wheel diameter while keeping the same overall tire diameter, by using a lower-profile tire. It changes the look and handling without affecting the speedometer.
No, when done correctly. Because overall diameter stays the same, the speedometer, odometer, ABS, and gearing all stay accurate.
Minus sizing is the opposite: a smaller wheel with a taller sidewall at the same overall diameter, often for winter tires or a softer ride.