Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 185/85-16 | 30/9.5-15 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 28.38 (720.9) | 29.99 (761.78) | 1.61 (40.88) 5.7% |
| Width inches (mm) | 7.28 (185) | 9.49 (241) | 2.2 (56) 30.3% |
| Circum. inches (mm) | 89.16 (2264.77) | 94.22 (2393.2) | 5.06 (128.43) 5.7% |
| Sidewall Height inches (mm) | 6.19 (157.25) | 7.5 (190.39) | 1.3 (33.14) 21.1% |
| Revolutions per mile (km) | 710.6 (441.54) | 672.46 (417.85) | -38.13 (-23.69) -5.4% |
30/9.5-15 Tires
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 21.13 mph (34.01 km/h) |
| 25 mph (40.23 km/h) | 26.42 mph (42.52 km/h) |
| 30 mph (48.28 km/h) | 31.7 mph (51.02 km/h) |
| 35 mph (56.33 km/h) | 36.98 mph (59.52 km/h) |
| 40 mph (64.37 km/h) | 42.27 mph (68.02 km/h) |
| 45 mph (72.42 km/h) | 47.55 mph (76.53 km/h) |
| 50 mph (80.47 km/h) | 52.84 mph (85.03 km/h) |
| 55 mph (88.51 km/h) | 58.12 mph (93.53 km/h) |
| 60 mph (96.56 km/h) | 63.4 mph (102.04 km/h) |
| 65 mph (104.61 km/h) | 68.69 mph (110.54 km/h) |
| 70 mph (112.65 km/h) | 73.97 mph (119.04 km/h) |
| 75 mph (120.7 km/h) | 79.25 mph (127.55 km/h) |
| 80 mph (128.75 km/h) | 84.54 mph (136.05 km/h) |
| 85 mph (136.79 km/h) | 89.82 mph (144.55 km/h) |
| 90 mph (144.84 km/h) | 95.1 mph (153.05 km/h) |
| 95 mph (152.89 km/h) | 100.39 mph (161.56 km/h) |
| 100 mph (160.93 km/h) | 105.67 mph (170.06 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1711 | 1988 | 2141 | 2236 | 2338 | 2410 | 2490 | 2585 | 2716 | 2847 | 2993 | 3109 | 3321 | 3554 | 3736 | 3852 | 3918 | 4158 | 4493 | 5221 |
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