Existing setup
Enter existing and proposed tire sizes, wheel widths and ET.
Free Tools No upload
100% FREE
Tire & Wheel Size Calculator
Compare tire sizes and wheel offset with diagrams, diameter, sidewall, rim shifts and theoretical speed changes. Free and local.
No sign-upNo uploadNo watermark
No sign-up No upload No watermark
| Measurement | Existing setup | New setup |
|---|---|---|
| Diameter | 631.9 mm | 634.3 mm |
| Sidewall height | 112.75 mm | 101.25 mm |
| Circumference | 1985.17 mm | 1992.71 mm |
Diameter change2.4mm
Circumference change0.379807%
Radius change1.2mm
Outer rim shift12.7mm
Inner rim shift12.7mm
Theoretical actual speed100.38km/h
Positive outer shift means further outward. Positive inner shift means less room on the suspension side.
Actual speed assumes the speedometer was calibrated to the existing tire; it scales with tire circumference.
Nominal, unloaded geometry only. Tire stretch, load, brakes, suspension and vehicle clearance are not modeled.
EXAMPLES
Try six wheel and tire comparisons.
Editable measurements, not vehicle-specific fitment recommendations.
THREE SIMPLE STEPS
Tire & Wheel Size Calculator
New setup
Compare nominal dimensions and signed rim-position changes.
Download report
Download report
Tire & Wheel Size Calculator FAQ
Will this confirm the wheels fit my car?
Nominal, unloaded geometry only. Tire stretch, load, brakes, suspension and vehicle clearance are not modeled.
What do positive rim shifts mean?
Positive outer shift means further outward. Positive inner shift means less room on the suspension side.
Why does the speed reading change?
Actual speed assumes the speedometer was calibrated to the existing tire; it scales with tire circumference.
How do I keep the results?
Download report
More free tools like this
All Free Tools
Tire & Wheel Size Calculator
Compare tire sizes and wheel offset with diagrams, diameter, sidewall, rim shifts and theoretical speed changes. Free and local.