Rim Width Calculator by Tire Size
Measuring width is where the tire is spec’d. Acceptable is the full range. Optimal is near measuring.
What it does
Looks up ETRTO/TRA approved rim-width ranges by tire section width and aspect. Reverse lookup lists common tire widths that include your rim.
How to use it
Enter a tire size, or enter a rim width in inches (the stamped J-width).
How to read the result
On the measuring rim, a 245 is supposed to measure 245 mm. Narrower rims pinch the tire; wider rims square it out. Stay inside the published min/max. The maker’s spec on that exact model always wins over this table.
What this does not calculate
Tables are ETRTO passenger/LT series, not every LT flotation or competition size. Run-flat, load range E and some SUV tires publish different ranges.
Does not stretch-fit or check inner-fender clearance of a squared-off tire.
Questions
- What happens on a rim that is too wide?
- The sidewall stands more upright, the tread can crown, and the tire may not bead safely. Steering feels darty. It can also void a warranty.
- Is flotation different?
- Yes. A 35x12.50 often lists 8–11" rims with ~10" preferred. This table is metric/P-metric first; flotation is a manufacturer chart.
Related tools
- Tire Stretch CalculatorThe verdict is the published rim-width table. A percentage is just how the picture looks.
- Plus Sizing CalculatorBigger rim, shorter sidewall — without accidentally lifting or lowering the car.
- Free Wheel Offset CalculatorMore positive offset tucks the wheel in. More width with the same offset pokes both ways.
Estimate — not a fitment approval.
