285/65R18
285/65R18 ships as an OEM size on the Chevrolet Silverado 1500, Toyota Tundra. At 32.59″ diameter with a 7.29″ sidewall (65% of section width), this size turns 619 revolutions per mile.
About 285/65R18
Factory fitments for 285/65R18 include the Chevrolet Silverado 1500, Toyota Tundra — meaning replacement tires in this size see steady demand and broad brand availability. At 32.59″ overall diameter, 285/65R18 turns 619 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 18″ rim pairing is typical for full-size truck, premium SUV, and sport-sedan platforms, so compatible wheels are easy to source new or used. Going one step shorter to 275/65R18 drops diameter by 1.57%, which stays within the ±3% fitment safe zone for most vehicles. Stepping up to 265/70R18 adds 0.06% 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 32.59″ 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 aliases285/65R18
- Diameter
- 32.59″ / 827.7mm
- Section Width
- 11.22″
- Sidewall
- 7.29″ / 185.25mm
- Circumference
- 102.37″
- Revs/Mile
- 619
265/65R18
- Diameter
- 31.56″ / 801.7mm
- Section Width
- 10.43″
- Sidewall
- 6.78″ / 172.25mm
- Circumference
- 99.16″
- Revs/Mile
- 639
Speedometer & Diameter Impact
At an indicated 60 mph, your actual speed is 58.12 mph (93.53 km/h). Your speedometer reads 3.14% high versus actual speed.