295/45R21
295/45R21 is uncommon as OEM fitment but appears as an aftermarket upsize option. At 31.45″ diameter with a 5.23″ sidewall (45% of section width), this size turns 641 revolutions per mile.
About 295/45R21
295/45R21 is less common as a factory fitment but is available as an aftermarket size, so SKU selection is narrower than mainstream OEM sizes. At 31.45″ overall diameter, 295/45R21 turns 641 revolutions per mile, which is the reference point the factory speedometer and odometer were calibrated against. The 45% aspect ratio gives it a low-profile sidewall that delivers sharp steering response but transmits road imperfections. The 21″ 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 285/45R21 drops diameter by 1.13%, which stays within the ±3% fitment safe zone for most vehicles. Stepping up to 275/50R21 adds 1.19% 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 31.45″ 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 aliases295/45R21
- Diameter
- 31.45″ / 798.9mm
- Section Width
- 11.61″
- Sidewall
- 5.23″ / 132.75mm
- Circumference
- 98.81″
- Revs/Mile
- 641
275/45R21
- Diameter
- 30.74″ / 780.9mm
- Section Width
- 10.83″
- Sidewall
- 4.87″ / 123.75mm
- Circumference
- 96.59″
- Revs/Mile
- 656
Speedometer & Diameter Impact
At an indicated 60 mph, your actual speed is 58.65 mph (94.39 km/h). Your speedometer reads 2.25% high versus actual speed.