295/35R20 vs 255/45R20
255/45R20 is outside the ±3% rule as a replacement for 295/35R20: the diameter differs by +3.22%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
Speedometer and odometer
With 255/45R20 on a car calibrated for 295/35R20, the speedometer reads 58.1 mph when you're really doing 60, and the odometer under-counts by 3.2%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 31.0 mph |
| 45 mph | 46.4 mph |
| 60 mph | 61.9 mph |
| 70 mph | 72.3 mph |
| 80 mph | 82.6 mph |
Other sizes close to 295/35R20
- 295/35R20 vs 245/45R20+1.96%
- 295/35R20 vs 275/40R20+1.89%
- 295/35R20 vs 245/40R20-1.47%
- 295/35R20 vs 255/45R19-0.34%
- 295/35R20 vs 245/35R20-4.90%
- 295/35R20 vs 255/35R20-3.92%
- 295/35R20 vs 255/40R20-0.35%
- 295/35R20 vs 275/35R20-1.96%
- 295/35R20 vs 235/50R19+0.43%
- 295/35R20 vs 265/45R20+4.48%
- 295/35R20 vs 285/35R20-0.98%
- 295/35R20 vs 315/35R20+1.96%
Questions
Can I replace 295/35R20 with 255/45R20?
255/45R20 is outside the ±3% rule as a replacement for 295/35R20: the diameter differs by +3.22%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
What's the difference between 295/35R20 and 255/45R20?
255/45R20 is 0.91" taller and 40 mm narrower; the sidewall is +0.45". At an indicated 60 mph you'd actually be doing 61.9 mph.
Will 255/45R20 fit on 295/35R20 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.