Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 255/40-21 | 235/55-21 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 29.03 (737.4) | 31.18 (791.9) | 2.15 (54.5) 7.4% |
| Width inches (mm) | 10.04 (255) | 9.25 (235) | -0.79 (-20) -7.8% |
| Circum. inches (mm) | 91.21 (2316.61) | 97.95 (2487.83) | 6.74 (171.22) 7.4% |
| Sidewall Height inches (mm) | 4.02 (102) | 5.09 (129.25) | 1.07 (27.25) 26.7% |
| Revolutions per mile (km) | 694.7 (431.66) | 646.89 (401.96) | -47.81 (-29.71) -6.9% |
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 21.48 mph (34.57 km/h) |
| 25 mph (40.23 km/h) | 26.85 mph (43.21 km/h) |
| 30 mph (48.28 km/h) | 32.22 mph (51.85 km/h) |
| 35 mph (56.33 km/h) | 37.59 mph (60.49 km/h) |
| 40 mph (64.37 km/h) | 42.96 mph (69.13 km/h) |
| 45 mph (72.42 km/h) | 48.33 mph (77.77 km/h) |
| 50 mph (80.47 km/h) | 53.7 mph (86.41 km/h) |
| 55 mph (88.51 km/h) | 59.06 mph (95.06 km/h) |
| 60 mph (96.56 km/h) | 64.43 mph (103.7 km/h) |
| 65 mph (104.61 km/h) | 69.8 mph (112.34 km/h) |
| 70 mph (112.65 km/h) | 75.17 mph (120.98 km/h) |
| 75 mph (120.7 km/h) | 80.54 mph (129.62 km/h) |
| 80 mph (128.75 km/h) | 85.91 mph (138.26 km/h) |
| 85 mph (136.79 km/h) | 91.28 mph (146.9 km/h) |
| 90 mph (144.84 km/h) | 96.65 mph (155.55 km/h) |
| 95 mph (152.89 km/h) | 102.02 mph (164.19 km/h) |
| 100 mph (160.93 km/h) | 107.39 mph (172.83 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1646 | 1912 | 2060 | 2151 | 2249 | 2319 | 2396 | 2487 | 2613 | 2739 | 2879 | 2991 | 3194 | 3419 | 3594 | 3706 | 3769 | 4000 | 4322 | 5023 |
Better Fuel Economy Factory Ratios Increased Power
