295/40R20 vs 235/55R20
235/55R20 is outside the ±3% rule as a replacement for 295/40R20: the diameter differs by +3.02%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
Speedometer and odometer
With 235/55R20 on a car calibrated for 295/40R20, the speedometer reads 58.2 mph when you're really doing 60, and the odometer under-counts by 3.0%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 30.9 mph |
| 45 mph | 46.4 mph |
| 60 mph | 61.8 mph |
| 70 mph | 72.1 mph |
| 80 mph | 82.4 mph |
Other sizes close to 295/40R20
- 295/40R20 vs 235/55R19-0.39%
- 295/40R20 vs 245/45R20-2.08%
- 295/40R20 vs 255/45R20-0.87%
- 295/40R20 vs 255/50R19-0.86%
- 295/40R20 vs 275/40R20-2.15%
- 295/40R20 vs 255/50R20+2.55%
- 295/40R20 vs 265/50R20+3.90%
- 295/40R20 vs 245/50R20+1.21%
- 295/40R20 vs 275/45R20+1.55%
- 295/40R20 vs 255/40R20-4.30%
- 295/40R20 vs 265/45R20+0.34%
- 295/40R20 vs 285/35R20-4.91%
Questions
Can I replace 295/40R20 with 235/55R20?
235/55R20 is outside the ±3% rule as a replacement for 295/40R20: the diameter differs by +3.02%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
What's the difference between 295/40R20 and 235/55R20?
235/55R20 is 0.89" taller and 60 mm narrower; the sidewall is +0.44". At an indicated 60 mph you'd actually be doing 61.8 mph.
Will 235/55R20 fit on 295/40R20 wheels?
Both use a 20" rim, so the wheel diameter matches; check the wheel's width range for a 235 mm tire and the fender clearance.