Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 285/30-21 | 285/40-21 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 27.73 (704.4) | 29.98 (761.4) | 2.24 (57) 8.1% |
| Width inches (mm) | 11.22 (285) | 11.22 (285) | 0 (0) 0% |
| Circum. inches (mm) | 87.12 (2212.94) | 94.17 (2392.01) | 7.05 (179.07) 8.1% |
| Sidewall Height inches (mm) | 3.37 (85.5) | 4.49 (114) | 1.12 (28.5) 33.3% |
| Revolutions per mile (km) | 727.24 (451.89) | 672.8 (418.06) | -54.44 (-33.83) -7.5% |
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 21.62 mph (34.79 km/h) |
| 25 mph (40.23 km/h) | 27.02 mph (43.49 km/h) |
| 30 mph (48.28 km/h) | 32.43 mph (52.19 km/h) |
| 35 mph (56.33 km/h) | 37.83 mph (60.89 km/h) |
| 40 mph (64.37 km/h) | 43.24 mph (69.58 km/h) |
| 45 mph (72.42 km/h) | 48.64 mph (78.28 km/h) |
| 50 mph (80.47 km/h) | 54.05 mph (86.98 km/h) |
| 55 mph (88.51 km/h) | 59.45 mph (95.68 km/h) |
| 60 mph (96.56 km/h) | 64.86 mph (104.37 km/h) |
| 65 mph (104.61 km/h) | 70.26 mph (113.07 km/h) |
| 70 mph (112.65 km/h) | 75.66 mph (121.77 km/h) |
| 75 mph (120.7 km/h) | 81.07 mph (130.47 km/h) |
| 80 mph (128.75 km/h) | 86.47 mph (139.17 km/h) |
| 85 mph (136.79 km/h) | 91.88 mph (147.86 km/h) |
| 90 mph (144.84 km/h) | 97.28 mph (156.56 km/h) |
| 95 mph (152.89 km/h) | 102.69 mph (165.26 km/h) |
| 100 mph (160.93 km/h) | 108.09 mph (173.96 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1712 | 1989 | 2142 | 2237 | 2339 | 2412 | 2492 | 2586 | 2718 | 2849 | 2994 | 3111 | 3322 | 3555 | 3738 | 3854 | 3920 | 4160 | 4495 | 5224 |
Better Fuel Economy Factory Ratios Increased Power
