245/60R18 vs 255/65R18
255/65R18 is outside the ±3% rule as a replacement for 245/60R18: the diameter differs by +4.99%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
Speedometer and odometer
With 255/65R18 on a car calibrated for 245/60R18, the speedometer reads 57.1 mph when you're really doing 60, and the odometer under-counts by 5.0%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 31.5 mph |
| 45 mph | 47.2 mph |
| 60 mph | 63.0 mph |
| 70 mph | 73.5 mph |
| 80 mph | 84.0 mph |
Other sizes close to 245/60R18
- 245/60R18 vs 235/60R18-1.60%
- 245/60R18 vs 235/55R18-4.73%
- 245/60R18 vs 265/60R18+3.19%
- 245/60R18 vs 225/60R18-3.19%
- 245/60R18 vs 245/65R17-0.12%
- 245/60R18 vs 255/55R18-1.80%
- 245/60R18 vs 235/65R18+1.53%
- 245/60R18 vs 245/55R19+0.12%
- 245/60R18 vs 265/50R19-0.48%
- 245/60R18 vs 255/60R18+1.60%
- 245/60R18 vs 245/55R18-3.26%
- 245/60R18 vs 275/60R18+4.79%
Questions
Can I replace 245/60R18 with 255/65R18?
255/65R18 is outside the ±3% rule as a replacement for 245/60R18: the diameter differs by +4.99%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
What's the difference between 245/60R18 and 255/65R18?
255/65R18 is 1.48" taller and 10 mm wider; the sidewall is +0.74". At an indicated 60 mph you'd actually be doing 63.0 mph.
Will 255/65R18 fit on 245/60R18 wheels?
Both use a 18" rim, so the wheel diameter matches; check the wheel's width range for a 255 mm tire and the fender clearance.