285/45R19 vs 235/50R20
235/50R20 is a safe swap for 285/45R19 by the usual ±3% rule: the diameter differs by +0.53%.
Speedometer and odometer
With 235/50R20 on a car calibrated for 285/45R19, the speedometer reads 59.7 mph when you're really doing 60, and the odometer under-counts by 0.5%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 30.2 mph |
| 45 mph | 45.2 mph |
| 60 mph | 60.3 mph |
| 70 mph | 70.4 mph |
| 80 mph | 80.4 mph |
Other sizes close to 285/45R19
- 285/45R19 vs 235/60R18+0.01%
- 285/45R19 vs 235/55R19+0.27%
- 285/45R19 vs 245/45R19-4.87%
- 285/45R19 vs 255/45R20-0.22%
- 285/45R19 vs 255/50R19-0.20%
- 285/45R19 vs 255/55R18-0.19%
- 285/45R19 vs 255/45R19-3.65%
- 285/45R19 vs 225/55R19-1.22%
- 285/45R19 vs 275/40R19-4.94%
- 285/45R19 vs 235/50R19-2.91%
- 285/45R19 vs 245/55R19+1.76%
- 285/45R19 vs 255/55R19+3.25%
Questions
Can I replace 285/45R19 with 235/50R20?
235/50R20 is a safe swap for 285/45R19 by the usual ±3% rule: the diameter differs by +0.53%.
What's the difference between 285/45R19 and 235/50R20?
235/50R20 is 0.15" taller and 50 mm narrower; the sidewall is -0.42". At an indicated 60 mph you'd actually be doing 60.3 mph.
Will 235/50R20 fit on 285/45R19 wheels?
No — 285/45R19 needs a 19" wheel and 235/50R20 a 20" wheel. This is a plus/minus-size swap that changes wheels too.