37x12.50R20 in metric
| Measure | Inches | Millimetres |
|---|---|---|
| Overall height | 37.00 in | 940 mm |
| Width | 12.50 in | 318 mm |
| Sidewall | 8.50 in | 216 mm |
| Wheel | 20 in | 508 mm |
| Revs per mile | 545.1 |
Flotation sizes are written as height × width R wheel in inches, so 37x12.50R20 is 37 in tall and 12.50 in wide by definition. Metric sizes are written in millimetres, so there is no exact twin: these are the closest calculated metric sizes on a 20 in wheel.
Closest calculated metric sizes
| Size | Height | Off by | Width |
|---|---|---|---|
| 335/65R20 (compare) | 37.1 in | +0.15 in | 13.2 in |
| 305/70R20 (compare) | 36.8 in | −0.19 in | 12.0 in |
| 315/70R20 (compare) | 37.4 in | +0.36 in | 12.4 in |
| 325/65R20 (compare) | 36.6 in | −0.37 in | 12.8 in |
| 295/75R20 (compare) | 37.4 in | +0.42 in | 11.6 in |
These are calculated combinations of standard widths and aspect ratios, not a list of tires that are sold: confirm a tire is made in that size, and that it suits your wheel width.
Moving up to 37x12.50R20 from a smaller tire
| From | Height change | 60 mph on the speedometer is really | Verdict |
|---|---|---|---|
| 315/70R17 | +7.7% (+2.64 in) | 64.6 mph | Big change |
| 295/70R18 | +8.0% (+2.74 in) | 64.8 mph | Big change |
| 275/65R20 | +8.6% (+2.93 in) | 65.2 mph | Big change |
Regearing
A tire this size is taller than most stock tires, so engine RPM falls at a given speed. See the gear ratio calculator and the regear chart.
Calculated from the size alone. Real tires vary a little by brand and model, and the loaded radius is a bit smaller. Confirm the wheel width range, clearance, load index and speed rating for your vehicle. See how to read a tire size, the load index chart and the speed rating chart.