275/65R20
275/65R20 ships as an OEM size on the Rivian R1S, Rivian R1T. At 34.07″ diameter with a 7.04″ sidewall (65% of section width), this size turns 592 revolutions per mile.
About 275/65R20
Factory fitments for 275/65R20 include the Rivian R1S, Rivian R1T — meaning replacement tires in this size see steady demand and broad brand availability. At 34.07″ overall diameter, 275/65R20 turns 592 revolutions per mile, which is the reference point the factory speedometer and odometer were calibrated against. The 65% 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 295/60R20 drops diameter by 0.40%, which stays within the ±3% fitment safe zone for most vehicles. Stepping up to 285/65R20 adds 1.50% 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 34.07″ 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 aliases275/65R20
- Diameter
- 34.07″ / 865.5mm
- Section Width
- 10.83″
- Sidewall
- 7.04″ / 178.75mm
- Circumference
- 107.05″
- Revs/Mile
- 592
255/65R20
- Diameter
- 33.05″ / 839.5mm
- Section Width
- 10.04″
- Sidewall
- 6.53″ / 165.75mm
- Circumference
- 103.83″
- Revs/Mile
- 610
Speedometer & Diameter Impact
At an indicated 60 mph, your actual speed is 58.2 mph (93.66 km/h). Your speedometer reads 3.00% high versus actual speed.