285/45R18
285/45R18 is uncommon as OEM fitment but appears as an aftermarket upsize option. At 28.10″ diameter with a 5.05″ sidewall (45% of section width), this size turns 718 revolutions per mile.
About 285/45R18
285/45R18 is less common as a factory fitment but is available as an aftermarket size, so SKU selection is narrower than mainstream OEM sizes. At 28.10″ overall diameter, 285/45R18 turns 718 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 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 275/45R18 drops diameter by 1.26%, which stays within the ±3% fitment safe zone for most vehicles. Stepping up to 265/50R18 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 28.10″ 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 aliases285/45R18
- Diameter
- 28.1″ / 713.7mm
- Section Width
- 11.22″
- Sidewall
- 5.05″ / 128.25mm
- Circumference
- 88.27″
- Revs/Mile
- 718
265/45R18
- Diameter
- 27.39″ / 695.7mm
- Section Width
- 10.43″
- Sidewall
- 4.69″ / 119.25mm
- Circumference
- 86.05″
- Revs/Mile
- 736
Speedometer & Diameter Impact
At an indicated 60 mph, your actual speed is 58.49 mph (94.13 km/h). Your speedometer reads 2.52% high versus actual speed.