265/55R18
265/55R18 is uncommon as OEM fitment but appears as an aftermarket upsize option. At 29.48″ diameter with a 5.74″ sidewall (55% of section width), this size turns 684 revolutions per mile.
About 265/55R18
265/55R18 is less common as a factory fitment but is available as an aftermarket size, so SKU selection is narrower than mainstream OEM sizes. At 29.48″ overall diameter, 265/55R18 turns 684 revolutions per mile, which is the reference point the factory speedometer and odometer were calibrated against. The 55% aspect ratio gives it a moderate sidewall suited to sporty street driving and responsive turn-in. 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 255/55R18 drops diameter by 1.47%, which stays within the ±3% fitment safe zone for most vehicles. Stepping up to 245/60R18 adds 0.33% 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 29.48″ 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 aliases265/55R18
- Diameter
- 29.48″ / 748.7mm
- Section Width
- 10.43″
- Sidewall
- 5.74″ / 145.75mm
- Circumference
- 92.6″
- Revs/Mile
- 684
245/55R18
- Diameter
- 28.61″ / 726.7mm
- Section Width
- 9.65″
- Sidewall
- 5.31″ / 134.75mm
- Circumference
- 89.88″
- Revs/Mile
- 705
Speedometer & Diameter Impact
At an indicated 60 mph, your actual speed is 58.24 mph (93.72 km/h). Your speedometer reads 2.94% high versus actual speed.