Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 255/30-21 | 255/40-21 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 27.02 (686.4) | 29.03 (737.4) | 2.01 (51) 7.4% |
| Width inches (mm) | 10.04 (255) | 10.04 (255) | 0 (0) 0% |
| Circum. inches (mm) | 84.9 (2156.39) | 91.21 (2316.61) | 6.31 (160.22) 7.4% |
| Sidewall Height inches (mm) | 3.01 (76.5) | 4.02 (102) | 1 (25.5) 33.3% |
| Revolutions per mile (km) | 746.31 (463.74) | 694.7 (431.66) | -51.62 (-32.07) -6.9% |
255/40-21 Tires
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 21.49 mph (34.58 km/h) |
| 25 mph (40.23 km/h) | 26.86 mph (43.22 km/h) |
| 30 mph (48.28 km/h) | 32.23 mph (51.87 km/h) |
| 35 mph (56.33 km/h) | 37.6 mph (60.51 km/h) |
| 40 mph (64.37 km/h) | 42.97 mph (69.16 km/h) |
| 45 mph (72.42 km/h) | 48.34 mph (77.8 km/h) |
| 50 mph (80.47 km/h) | 53.72 mph (86.45 km/h) |
| 55 mph (88.51 km/h) | 59.09 mph (95.09 km/h) |
| 60 mph (96.56 km/h) | 64.46 mph (103.74 km/h) |
| 65 mph (104.61 km/h) | 69.83 mph (112.38 km/h) |
| 70 mph (112.65 km/h) | 75.2 mph (121.02 km/h) |
| 75 mph (120.7 km/h) | 80.57 mph (129.67 km/h) |
| 80 mph (128.75 km/h) | 85.94 mph (138.31 km/h) |
| 85 mph (136.79 km/h) | 91.32 mph (146.96 km/h) |
| 90 mph (144.84 km/h) | 96.69 mph (155.6 km/h) |
| 95 mph (152.89 km/h) | 102.06 mph (164.25 km/h) |
| 100 mph (160.93 km/h) | 107.43 mph (172.89 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1768 | 2054 | 2212 | 2310 | 2415 | 2490 | 2573 | 2671 | 2806 | 2941 | 3092 | 3212 | 3430 | 3671 | 3859 | 3980 | 4047 | 4296 | 4642 | 5394 |
Better Fuel Economy Factory Ratios Increased Power
