245/60R20 vs 255/60R20
255/60R20 is a safe swap for 245/60R20 by the usual ±3% rule: the diameter differs by +1.50%.
Speedometer and odometer
With 255/60R20 on a car calibrated for 245/60R20, the speedometer reads 59.1 mph when you're really doing 60, and the odometer under-counts by 1.5%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 30.4 mph |
| 45 mph | 45.7 mph |
| 60 mph | 60.9 mph |
| 70 mph | 71.0 mph |
| 80 mph | 81.2 mph |
Other sizes close to 245/60R20
- 245/60R20 vs 275/55R20+1.06%
- 245/60R20 vs 275/60R20+4.49%
- 245/60R20 vs 255/50R20-4.86%
- 245/60R20 vs 265/50R20-3.62%
- 245/60R20 vs 255/55R20-1.68%
- 245/60R20 vs 235/55R20-4.43%
- 245/60R20 vs 265/60R20+2.99%
- 245/60R20 vs 285/55R20+2.43%
- 245/60R20 vs 275/50R20-2.37%
- 245/60R20 vs 33x12.50R20+4.51%
- 245/60R20 vs 295/55R20+3.80%
- 245/60R20 vs 285/50R20-1.12%
Questions
Can I replace 245/60R20 with 255/60R20?
255/60R20 is a safe swap for 245/60R20 by the usual ±3% rule: the diameter differs by +1.50%.
What's the difference between 245/60R20 and 255/60R20?
255/60R20 is 0.47" taller and 10 mm wider; the sidewall is +0.24". At an indicated 60 mph you'd actually be doing 60.9 mph.
Will 255/60R20 fit on 245/60R20 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.