255/70R18
255/70R18 ships as an OEM size on the Jeep Gladiator, Jeep Wrangler. At 32.06″ diameter with a 7.03″ sidewall (70% of section width), this size turns 629 revolutions per mile.
About 255/70R18
Factory fitments for 255/70R18 include the Jeep Gladiator, Jeep Wrangler — meaning replacement tires in this size see steady demand and broad brand availability. At 32.06″ overall diameter, 255/70R18 turns 629 revolutions per mile, which is the reference point the factory speedometer and odometer were calibrated against. The 70% aspect ratio gives it a tall, compliant sidewall that absorbs bumps well and protects rims off-road. 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 265/65R18 drops diameter by 1.54%, which stays within the ±3% fitment safe zone for most vehicles. Stepping up to 275/65R18 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 32.06″ 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 aliases255/70R18
- Diameter
- 32.06″ / 814.2mm
- Section Width
- 10.04″
- Sidewall
- 7.03″ / 178.5mm
- Circumference
- 100.7″
- Revs/Mile
- 629
245/65R18
- Diameter
- 30.54″ / 775.7mm
- Section Width
- 9.65″
- Sidewall
- 6.27″ / 159.25mm
- Circumference
- 95.94″
- Revs/Mile
- 660
Speedometer & Diameter Impact
At an indicated 60 mph, your actual speed is 57.16 mph (91.99 km/h). Your speedometer reads 4.73% high versus actual speed.