ElpiAuto37X13.50R20 in metric
A 37X13.50R20 is 37.0″ (940 mm) tall and 13.50″ (343 mm) wide on a 20″ wheel. Converted directly it reads 345/65R20; the nearest standard metric size is 335/65R20.
Your tire size
e.g. 235/75R15, 33X12.50R15, or 225/45R17 91V
Metric equivalents of 37X13.50R20
335/65R20 is a near-exact match: +0.4% in height and −8 mm in width. The others trade a little height for width, or the reverse — all on the same 20″ wheel, within the ±3% most makers accept.
| Size | Diameter | Height vs 37X13.50R20 | Width vs 37X13.50R20 |
|---|---|---|---|
| 335/65R20 | 37.1″ · 944 mm | +0.4% | −8 mm |
| 355/60R20 | 36.8″ · 934 mm | −0.6% | +12 mm |
| 345/65R20 | 37.7″ · 956 mm | +1.8% | +2 mm |
| 345/60R20 | 36.3″ · 922 mm | −1.9% | +2 mm |
| 325/65R20 | 36.6″ · 930 mm | −1.0% | −18 mm |
37X13.50R20 dimensions
Computed from the size code; moulded tires vary by brand by roughly 1–3%.
| Dimension | Inches | Millimetres |
|---|---|---|
| Overall diameter | 37.0″ | 940 |
| Section width | 13.50″ | 343 |
| Sidewall height | 8.50″ | 216 |
| Circumference | 116.2″ | 2952 |
| Revolutions per mile | 545 | — |
| Revolutions per km | — | 339 |
The same height on other wheels
If you are changing wheel diameter but want to keep a 37.0″ overall height, these metric sizes come closest (within 2%).
| Wheel | Size | Diameter | Difference |
|---|---|---|---|
| 15″ | 325/85R15 | 36.8″ | −0.7% |
| 16″ | 355/75R16 | 37.0″ | −0.1% |
| 17″ | 315/80R17 | 36.8″ | −0.4% |
| 18″ | 345/70R18 | 37.0″ | +0.0% |
| 22″ | 345/55R22 | 36.9″ | −0.2% |
Wheel width and neighbouring sizes
A 343 mm-wide tire mounts on 10.5–13.0″ wide wheels (the usual approved range; the middle is ideal).
One step down is 35X12.50R20: −5.4% in diameter. With a speedometer calibrated for 37X13.50R20, an indicated 60 mph would be 56.8 mph on 35X12.50R20.
Figures are geometric: overall diameter = wheel + 2 × sidewall, 25.4 mm per inch. Check the tire maker's data sheet for the exact moulded size before buying.