285/30R22 vs 255/40R22
255/40R22 is outside the ±3% rule as a replacement for 285/30R22: the diameter differs by +4.52%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
Speedometer and odometer
With 255/40R22 on a car calibrated for 285/30R22, the speedometer reads 57.4 mph when you're really doing 60, and the odometer under-counts by 4.5%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 31.4 mph |
| 45 mph | 47.0 mph |
| 60 mph | 62.7 mph |
| 70 mph | 73.2 mph |
| 80 mph | 83.6 mph |
Other sizes close to 285/30R22
- 285/30R22 vs 275/35R21-0.53%
- 285/30R22 vs 265/35R22+1.99%
- 285/30R22 vs 285/35R22+3.91%
- 285/30R22 vs 325/30R21-0.19%
- 285/30R22 vs 285/35R21+0.42%
- 285/30R22 vs 245/40R21-0.05%
- 285/30R22 vs 275/35R22+2.95%
- 285/30R22 vs 295/35R22+4.86%
- 285/30R22 vs 295/30R22+0.82%
- 285/30R22 vs 315/30R22+2.47%
- 285/30R22 vs 265/30R22-1.64%
- 285/30R22 vs 255/30R22-2.47%
Questions
Can I replace 285/30R22 with 255/40R22?
255/40R22 is outside the ±3% rule as a replacement for 285/30R22: the diameter differs by +4.52%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
What's the difference between 285/30R22 and 255/40R22?
255/40R22 is 1.30" taller and 30 mm narrower; the sidewall is +0.65". At an indicated 60 mph you'd actually be doing 62.7 mph.
Will 255/40R22 fit on 285/30R22 wheels?
Both use a 22" rim, so the wheel diameter matches; check the wheel's width range for a 255 mm tire and the fender clearance.