Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 275/65-20 | 37/12.5-20 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 34.07 (865.5) | 37.03 (940.48) | 2.95 (74.98) 8.7% |
| Width inches (mm) | 10.83 (275) | 12.52 (318) | 1.69 (43) 15.6% |
| Circum. inches (mm) | 107.05 (2719.05) | 116.32 (2954.61) | 9.27 (235.56) 8.7% |
| Sidewall Height inches (mm) | 7.04 (178.75) | 8.51 (216.24) | 1.48 (37.49) 21% |
| Revolutions per mile (km) | 591.88 (367.78) | 544.69 (338.45) | -47.19 (-29.32) -8% |
37/12.5-20 Tires
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 21.73 mph (34.98 km/h) |
| 25 mph (40.23 km/h) | 27.17 mph (43.72 km/h) |
| 30 mph (48.28 km/h) | 32.6 mph (52.46 km/h) |
| 35 mph (56.33 km/h) | 38.03 mph (61.21 km/h) |
| 40 mph (64.37 km/h) | 43.47 mph (69.95 km/h) |
| 45 mph (72.42 km/h) | 48.9 mph (78.69 km/h) |
| 50 mph (80.47 km/h) | 54.33 mph (87.44 km/h) |
| 55 mph (88.51 km/h) | 59.76 mph (96.18 km/h) |
| 60 mph (96.56 km/h) | 65.2 mph (104.93 km/h) |
| 65 mph (104.61 km/h) | 70.63 mph (113.67 km/h) |
| 70 mph (112.65 km/h) | 76.06 mph (122.41 km/h) |
| 75 mph (120.7 km/h) | 81.5 mph (131.16 km/h) |
| 80 mph (128.75 km/h) | 86.93 mph (139.9 km/h) |
| 85 mph (136.79 km/h) | 92.36 mph (148.65 km/h) |
| 90 mph (144.84 km/h) | 97.8 mph (157.39 km/h) |
| 95 mph (152.89 km/h) | 103.23 mph (166.13 km/h) |
| 100 mph (160.93 km/h) | 108.66 mph (174.88 km/h) |
| 2.35 | 2.73 | 2.94 | 3.07 | 3.21 | 3.31 | 3.42 | 3.55 | 3.73 | 3.91 | 4.11 | 4.27 | 4.56 | 4.88 | 5.13 | 5.29 | 5.38 | 5.71 | 6.17 | 7.17 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1386 | 1610 | 1734 | 1811 | 1893 | 1952 | 2017 | 2094 | 2200 | 2306 | 2424 | 2519 | 2690 | 2878 | 3026 | 3120 | 3173 | 3368 | 3639 | 4229 |
Better Fuel Economy Factory Ratios Increased Power
