285/35R19 vs 255/35R20
255/35R20 is a safe swap for 285/35R19 by the usual ±3% rule: the diameter differs by +0.65%.
Speedometer and odometer
With 255/35R20 on a car calibrated for 285/35R19, the speedometer reads 59.6 mph when you're really doing 60, and the odometer under-counts by 0.6%.
| 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 | 80.5 mph |
Other sizes close to 285/35R19
- 285/35R19 vs 245/45R18-0.65%
- 285/35R19 vs 245/45R19+3.08%
- 285/35R19 vs 245/40R19-0.51%
- 285/35R19 vs 225/50R18+0.01%
- 285/35R19 vs 235/40R19-1.69%
- 285/35R19 vs 255/40R19+0.66%
- 285/35R19 vs 255/35R19-3.08%
- 285/35R19 vs 255/45R19+4.40%
- 285/35R19 vs 275/35R19-1.03%
- 285/35R19 vs 275/40R19+3.01%
- 285/35R19 vs 245/35R20-0.38%
- 285/35R19 vs 245/35R19-4.10%
Questions
Can I replace 285/35R19 with 255/35R20?
255/35R20 is a safe swap for 285/35R19 by the usual ±3% rule: the diameter differs by +0.65%.
What's the difference between 285/35R19 and 255/35R20?
255/35R20 is 0.17" taller and 30 mm narrower; the sidewall is -0.41". At an indicated 60 mph you'd actually be doing 60.4 mph.
Will 255/35R20 fit on 285/35R19 wheels?
No — 285/35R19 needs a 19" wheel and 255/35R20 a 20" wheel. This is a plus/minus-size swap that changes wheels too.