295/40R20 vs 255/50R20
255/50R20 is a safe swap for 295/40R20 by the usual ±3% rule: the diameter differs by +2.55%.
Speedometer and odometer
With 255/50R20 on a car calibrated for 295/40R20, the speedometer reads 58.5 mph when you're really doing 60, and the odometer under-counts by 2.6%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 30.8 mph |
| 45 mph | 46.1 mph |
| 60 mph | 61.5 mph |
| 70 mph | 71.8 mph |
| 80 mph | 82.0 mph |
Other sizes close to 295/40R20
- 295/40R20 vs 235/55R19-0.39%
- 295/40R20 vs 245/45R20-2.08%
- 295/40R20 vs 255/45R20-0.87%
- 295/40R20 vs 255/50R19-0.86%
- 295/40R20 vs 275/40R20-2.15%
- 295/40R20 vs 265/50R20+3.90%
- 295/40R20 vs 245/50R20+1.21%
- 295/40R20 vs 275/45R20+1.55%
- 295/40R20 vs 235/55R20+3.02%
- 295/40R20 vs 255/40R20-4.30%
- 295/40R20 vs 265/45R20+0.34%
- 295/40R20 vs 285/35R20-4.91%
Questions
Can I replace 295/40R20 with 255/50R20?
255/50R20 is a safe swap for 295/40R20 by the usual ±3% rule: the diameter differs by +2.55%.
What's the difference between 295/40R20 and 255/50R20?
255/50R20 is 0.75" taller and 40 mm narrower; the sidewall is +0.37". At an indicated 60 mph you'd actually be doing 61.5 mph.
Will 255/50R20 fit on 295/40R20 wheels?
Both use a 20" rim, so the wheel diameter matches; check the wheel's width range for a 255 mm tire and the fender clearance.