305/40R22 vs 305/45R22
305/45R22 is outside the ±3% rule as a replacement for 305/40R22: the diameter differs by +3.80%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
Speedometer and odometer
With 305/45R22 on a car calibrated for 305/40R22, the speedometer reads 57.8 mph when you're really doing 60, and the odometer under-counts by 3.8%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 31.1 mph |
| 45 mph | 46.7 mph |
| 60 mph | 62.3 mph |
| 70 mph | 72.7 mph |
| 80 mph | 83.0 mph |
Other sizes close to 305/40R22
- 305/40R22 vs 285/45R22+1.56%
- 305/40R22 vs 275/50R22+3.86%
- 305/40R22 vs 275/40R22-2.99%
- 305/40R22 vs 265/40R22-3.99%
- 305/40R22 vs 285/40R22-1.99%
- 305/40R22 vs 33x12.50R22+4.41%
- 305/40R22 vs 275/45R22+0.44%
- 305/40R22 vs 325/35R22-2.06%
- 305/40R22 vs 315/35R22-2.93%
- 305/40R22 vs 295/35R22-4.67%
- 305/40R22 vs 295/40R22-1.00%
- 305/40R22 vs 255/40R22-4.98%
Questions
Can I replace 305/40R22 with 305/45R22?
305/45R22 is outside the ±3% rule as a replacement for 305/40R22: the diameter differs by +3.80%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
What's the difference between 305/40R22 and 305/45R22?
305/45R22 is 1.20" taller and 0 mm wider; the sidewall is +0.60". At an indicated 60 mph you'd actually be doing 62.3 mph.
Will 305/45R22 fit on 305/40R22 wheels?
Both use a 22" rim, so the wheel diameter matches; check the wheel's width range for a 305 mm tire and the fender clearance.