305/40R22
305/40R22 is uncommon as OEM fitment but appears as an aftermarket upsize option. At 31.61″ diameter with a 4.80″ sidewall (40% of section width), this size turns 638 revolutions per mile.
About 305/40R22
305/40R22 is less common as a factory fitment but is available as an aftermarket size, so SKU selection is narrower than mainstream OEM sizes. At 31.61″ overall diameter, 305/40R22 turns 638 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 22″ rim pairing is typical for heavy-duty, off-road-lifted, and show-build applications, so compatible wheels are easy to source new or used. Going one step shorter to 295/40R22 drops diameter by 1.00%, which stays within the ±3% fitment safe zone for most vehicles. Stepping up to 285/45R22 adds 1.56% 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 31.61″ 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 aliases305/40R22
- Diameter
- 31.61″ / 802.8mm
- Section Width
- 12.01″
- Sidewall
- 4.8″ / 122mm
- Circumference
- 99.29″
- Revs/Mile
- 638
285/40R22
- Diameter
- 30.98″ / 786.8mm
- Section Width
- 11.22″
- Sidewall
- 4.49″ / 114mm
- Circumference
- 97.32″
- Revs/Mile
- 651
Speedometer & Diameter Impact
At an indicated 60 mph, your actual speed is 58.8 mph (94.64 km/h). Your speedometer reads 1.99% high versus actual speed.