Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 305/25-21 | 245/30-21 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 27 (685.9) | 26.79 (680.4) | -0.22 (-5.5) -0.8% |
| Width inches (mm) | 12.01 (305) | 9.65 (245) | -2.36 (-60) -19.7% |
| Circum. inches (mm) | 84.84 (2154.82) | 84.16 (2137.54) | -0.68 (-17.28) -0.8% |
| Sidewall Height inches (mm) | 3 (76.25) | 2.89 (73.5) | -0.11 (-2.75) -3.6% |
| Revolutions per mile (km) | 746.86 (464.08) | 752.9 (467.83) | 6.04 (3.75) 0.8% |
245/30-21 Tires
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 19.84 mph (31.93 km/h) |
| 25 mph (40.23 km/h) | 24.8 mph (39.91 km/h) |
| 30 mph (48.28 km/h) | 29.76 mph (47.89 km/h) |
| 35 mph (56.33 km/h) | 34.72 mph (55.88 km/h) |
| 40 mph (64.37 km/h) | 39.68 mph (63.86 km/h) |
| 45 mph (72.42 km/h) | 44.64 mph (71.84 km/h) |
| 50 mph (80.47 km/h) | 49.6 mph (79.82 km/h) |
| 55 mph (88.51 km/h) | 54.56 mph (87.8 km/h) |
| 60 mph (96.56 km/h) | 59.52 mph (95.79 km/h) |
| 65 mph (104.61 km/h) | 64.48 mph (103.77 km/h) |
| 70 mph (112.65 km/h) | 69.44 mph (111.75 km/h) |
| 75 mph (120.7 km/h) | 74.4 mph (119.73 km/h) |
| 80 mph (128.75 km/h) | 79.36 mph (127.72 km/h) |
| 85 mph (136.79 km/h) | 84.32 mph (135.7 km/h) |
| 90 mph (144.84 km/h) | 89.28 mph (143.68 km/h) |
| 95 mph (152.89 km/h) | 94.24 mph (151.66 km/h) |
| 100 mph (160.93 km/h) | 99.2 mph (159.64 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1916 | 2226 | 2397 | 2503 | 2617 | 2699 | 2788 | 2894 | 3041 | 3188 | 3351 | 3481 | 3718 | 3979 | 4183 | 4313 | 4386 | 4655 | 5030 | 5846 |
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