295/45R20 vs 305/50R20
305/50R20 is outside the ±3% rule as a replacement for 295/45R20: the diameter differs by +5.11%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
Speedometer and odometer
With 305/50R20 on a car calibrated for 295/45R20, the speedometer reads 57.1 mph when you're really doing 60, and the odometer under-counts by 5.1%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 31.5 mph |
| 45 mph | 47.3 mph |
| 60 mph | 63.1 mph |
| 70 mph | 73.6 mph |
| 80 mph | 84.1 mph |
Other sizes close to 295/45R20
- 295/45R20 vs 275/55R20+4.78%
- 295/45R20 vs 255/45R20-4.65%
- 295/45R20 vs 255/50R20-1.36%
- 295/45R20 vs 265/50R20-0.06%
- 295/45R20 vs 245/50R20-2.65%
- 295/45R20 vs 275/45R20-2.33%
- 295/45R20 vs 255/55R20+1.94%
- 295/45R20 vs 235/55R20-0.90%
- 295/45R20 vs 265/45R20-3.49%
- 295/45R20 vs 275/50R20+1.23%
- 295/45R20 vs 275/45R21+0.96%
- 295/45R20 vs 295/40R20-3.81%
Questions
Can I replace 295/45R20 with 305/50R20?
305/50R20 is outside the ±3% rule as a replacement for 295/45R20: the diameter differs by +5.11%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
What's the difference between 295/45R20 and 305/50R20?
305/50R20 is 1.56" taller and 10 mm wider; the sidewall is +0.78". At an indicated 60 mph you'd actually be doing 63.1 mph.
Will 305/50R20 fit on 295/45R20 wheels?
Both use a 20" rim, so the wheel diameter matches; check the wheel's width range for a 305 mm tire and the fender clearance.