245/60R20 vs 33x12.50R20
33x12.50R20 is outside the ±3% rule as a replacement for 245/60R20: the diameter differs by +4.51%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
Side by side
| 245/60R20 | 33x12.50R20 | Difference | |
|---|---|---|---|
| Overall diameter | 31.57" | 33.00" | +1.43" (+4.51%) |
| Section width | 245 mm | 318 mm | +73 mm |
| Sidewall | 5.79" | 6.50" | +0.71" |
| Rim | 20" | 20" | same |
| Circumference | 99.2" | 103.7" | +4.5" |
| Revs per mile | 639 | 611 | -28 |
| Ride height | — | — | +0.71" |
| Speedometer reads 60 mph | 60.0 | 62.7 | +2.7 mph |
Speedometer and odometer
With 33x12.50R20 on a car calibrated for 245/60R20, the speedometer reads 57.4 mph when you're really doing 60, and the odometer under-counts by 4.5%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 31.4 mph |
| 45 mph | 47.0 mph |
| 60 mph | 62.7 mph |
| 70 mph | 73.2 mph |
| 80 mph | 83.6 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 295/55R20+3.80%
- 245/60R20 vs 285/50R20-1.12%
- 245/60R20 vs 305/50R20+1.37%
Questions
Can I replace 245/60R20 with 33x12.50R20?
33x12.50R20 is outside the ±3% rule as a replacement for 245/60R20: the diameter differs by +4.51%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
What's the difference between 245/60R20 and 33x12.50R20?
33x12.50R20 is 1.43" taller and 73 mm wider; the sidewall is +0.71". At an indicated 60 mph you'd actually be doing 62.7 mph.
Will 33x12.50R20 fit on 245/60R20 wheels?
Both use a 20" rim, so the wheel diameter matches; check the wheel's width range for a 318 mm tire and the fender clearance.