255/60R20
255/60R20 is uncommon as OEM fitment but appears as an aftermarket upsize option. At 32.05″ diameter with a 6.02″ sidewall (60% of section width), this size turns 629 revolutions per mile.
About 255/60R20
255/60R20 is less common as a factory fitment but is available as an aftermarket size, so SKU selection is narrower than mainstream OEM sizes. At 32.05″ overall diameter, 255/60R20 turns 629 revolutions per mile, which is the reference point the factory speedometer and odometer were calibrated against. The 60% aspect ratio gives it a balanced sidewall — enough compliance for daily comfort without vague steering. The 20″ rim pairing is typical for luxury SUV and performance-oriented platforms, so compatible wheels are easy to source new or used. Going one step shorter to 235/65R20 drops diameter by 0.06%, which stays within the ±3% fitment safe zone for most vehicles. Stepping up to 245/65R20 adds 1.54% diameter — also inside the safe window, with marginally taller ride height. If you are shopping for a direct replacement, any tire within roughly ±0.7″ of the 32.05″ stock diameter (about ±2% in percentage terms) will keep ABS, TPMS, and odometer readings inside the vehicle's designed tolerance.
Compare with another size
275/65R18 or "33" for inch aliases255/60R20
- Diameter
- 32.05″ / 814mm
- Section Width
- 10.04″
- Sidewall
- 6.02″ / 153mm
- Circumference
- 100.68″
- Revs/Mile
- 629
235/60R20
- Diameter
- 31.1″ / 790mm
- Section Width
- 9.25″
- Sidewall
- 5.55″ / 141mm
- Circumference
- 97.71″
- Revs/Mile
- 648
Speedometer & Diameter Impact
At an indicated 60 mph, your actual speed is 58.23 mph (93.71 km/h). Your speedometer reads 2.95% high versus actual speed.