245/40R20
245/40R20 ships as an OEM size on the Chevrolet Camaro. At 27.72″ diameter with a 3.86″ sidewall (40% of section width), this size turns 728 revolutions per mile.
About 245/40R20
Factory fitments for 245/40R20 include the Chevrolet Camaro — meaning replacement tires in this size see steady demand and broad brand availability. At 27.72″ overall diameter, 245/40R20 turns 728 revolutions per mile, which is the reference point the factory speedometer and odometer were calibrated against. The 40% aspect ratio gives it a low-profile sidewall that delivers sharp steering response but transmits road imperfections. 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 235/40R20 drops diameter by 1.14%, which stays within the ±3% fitment safe zone for most vehicles. Stepping up to 255/40R20 adds 1.14% 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 27.72″ 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 aliases245/40R20
- Diameter
- 27.72″ / 704mm
- Section Width
- 9.65″
- Sidewall
- 3.86″ / 98mm
- Circumference
- 87.07″
- Revs/Mile
- 728
235/35R20
- Diameter
- 26.48″ / 672.5mm
- Section Width
- 9.25″
- Sidewall
- 3.24″ / 82.25mm
- Circumference
- 83.18″
- Revs/Mile
- 762
Speedometer & Diameter Impact
At an indicated 60 mph, your actual speed is 57.32 mph (92.24 km/h). Your speedometer reads 4.47% high versus actual speed.