275/50R19 vs 255/50R20
255/50R20 is a safe swap for 275/50R19 by the usual ±3% rule: the diameter differs by +0.71%.
Speedometer and odometer
With 255/50R20 on a car calibrated for 275/50R19, the speedometer reads 59.6 mph when you're really doing 60, and the odometer under-counts by 0.7%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 30.2 mph |
| 45 mph | 45.3 mph |
| 60 mph | 60.4 mph |
| 70 mph | 70.5 mph |
| 80 mph | 80.6 mph |
Other sizes close to 275/50R19
- 275/50R19 vs 235/55R19-2.18%
- 275/50R19 vs 255/50R19-2.64%
- 275/50R19 vs 245/60R18-0.84%
- 275/50R19 vs 235/65R18+0.67%
- 275/50R19 vs 245/50R20-0.61%
- 275/50R19 vs 275/45R20-0.28%
- 275/50R19 vs 225/55R19-3.63%
- 275/50R19 vs 245/55R19-0.73%
- 275/50R19 vs 255/55R19+0.73%
- 275/50R19 vs 255/60R19+4.09%
- 275/50R19 vs 265/50R19-1.32%
- 275/50R19 vs 245/50R19-3.96%
Questions
Can I replace 275/50R19 with 255/50R20?
255/50R20 is a safe swap for 275/50R19 by the usual ±3% rule: the diameter differs by +0.71%.
What's the difference between 275/50R19 and 255/50R20?
255/50R20 is 0.21" taller and 20 mm narrower; the sidewall is -0.39". At an indicated 60 mph you'd actually be doing 60.4 mph.
Will 255/50R20 fit on 275/50R19 wheels?
No — 275/50R19 needs a 19" wheel and 255/50R20 a 20" wheel. This is a plus/minus-size swap that changes wheels too.