285/40R19
285/40R19 is uncommon as OEM fitment but appears as an aftermarket upsize option. At 27.98″ diameter with a 4.49″ sidewall (40% of section width), this size turns 721 revolutions per mile.
About 285/40R19
285/40R19 is less common as a factory fitment but is available as an aftermarket size, so SKU selection is narrower than mainstream OEM sizes. At 27.98″ overall diameter, 285/40R19 turns 721 revolutions per mile, which is the reference point the factory speedometer and odometer were calibrated against. The 40% aspect ratio gives it a low-profile sidewall that delivers sharp steering response but transmits road imperfections. The 19″ 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 275/40R19 drops diameter by 1.13%, which stays within the ±3% fitment safe zone for most vehicles. Stepping up to 295/40R19 adds 1.13% 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 27.98″ 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 aliases285/40R19
- Diameter
- 27.98″ / 710.6mm
- Section Width
- 11.22″
- Sidewall
- 4.49″ / 114mm
- Circumference
- 87.89″
- Revs/Mile
- 721
265/40R19
- Diameter
- 27.35″ / 694.6mm
- Section Width
- 10.43″
- Sidewall
- 4.17″ / 106mm
- Circumference
- 85.91″
- Revs/Mile
- 738
Speedometer & Diameter Impact
At an indicated 60 mph, your actual speed is 58.65 mph (94.39 km/h). Your speedometer reads 2.25% high versus actual speed.