275/70R18
275/70R18 is uncommon as OEM fitment but appears as an aftermarket upsize option. At 33.16″ diameter with a 7.58″ sidewall (70% of section width), this size turns 608 revolutions per mile.
About 275/70R18
275/70R18 is less common as a factory fitment but is available as an aftermarket size, so SKU selection is narrower than mainstream OEM sizes. At 33.16″ overall diameter, 275/70R18 turns 608 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 295/65R18 drops diameter by 0.18%, which stays within the ±3% fitment safe zone for most vehicles. If you are shopping for a direct replacement, any tire within roughly ±0.7″ of the 33.16″ 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 aliases275/70R18
- Diameter
- 33.16″ / 842.2mm
- Section Width
- 10.83″
- Sidewall
- 7.58″ / 192.5mm
- Circumference
- 104.17″
- Revs/Mile
- 608
255/70R18
- Diameter
- 32.06″ / 814.2mm
- Section Width
- 10.04″
- Sidewall
- 7.03″ / 178.5mm
- Circumference
- 100.7″
- Revs/Mile
- 629
Speedometer & Diameter Impact
At an indicated 60 mph, your actual speed is 58.01 mph (93.35 km/h). Your speedometer reads 3.32% high versus actual speed.