315/30R22 vs 285/40R22
285/40R22 is outside the ±3% rule as a replacement for 315/30R22: the diameter differs by +5.22%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
Speedometer and odometer
With 285/40R22 on a car calibrated for 315/30R22, the speedometer reads 57.0 mph when you're really doing 60, and the odometer under-counts by 5.2%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 31.6 mph |
| 45 mph | 47.3 mph |
| 60 mph | 63.1 mph |
| 70 mph | 73.7 mph |
| 80 mph | 84.2 mph |
Other sizes close to 315/30R22
- 315/30R22 vs 265/40R21-0.32%
- 315/30R22 vs 275/40R22+4.15%
- 315/30R22 vs 265/40R22+3.08%
- 315/30R22 vs 265/35R22-0.47%
- 315/30R22 vs 285/35R22+1.40%
- 315/30R22 vs 275/40R21+0.75%
- 315/30R22 vs 315/35R21+0.82%
- 315/30R22 vs 275/35R22+0.47%
- 315/30R22 vs 295/35R22+2.34%
- 315/30R22 vs 315/35R22+4.21%
- 315/30R22 vs 285/30R22-2.41%
- 315/30R22 vs 295/30R22-1.60%
Questions
Can I replace 315/30R22 with 285/40R22?
285/40R22 is outside the ±3% rule as a replacement for 315/30R22: the diameter differs by +5.22%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
What's the difference between 315/30R22 and 285/40R22?
285/40R22 is 1.54" taller and 30 mm narrower; the sidewall is +0.77". At an indicated 60 mph you'd actually be doing 63.1 mph.
Will 285/40R22 fit on 315/30R22 wheels?
Both use a 22" rim, so the wheel diameter matches; check the wheel's width range for a 285 mm tire and the fender clearance.