Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 265/30-21 | 255/40-21 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 27.26 (692.4) | 29.03 (737.4) | 1.77 (45) 6.5% |
| Width inches (mm) | 10.43 (265) | 10.04 (255) | -0.39 (-10) -3.8% |
| Circum. inches (mm) | 85.64 (2175.24) | 91.21 (2316.61) | 5.57 (141.37) 6.5% |
| Sidewall Height inches (mm) | 3.13 (79.5) | 4.02 (102) | 0.89 (22.5) 28.3% |
| Revolutions per mile (km) | 739.85 (459.72) | 694.7 (431.66) | -45.15 (-28.05) -6.1% |
255/40-21 Tires
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 21.3 mph (34.28 km/h) |
| 25 mph (40.23 km/h) | 26.62 mph (42.85 km/h) |
| 30 mph (48.28 km/h) | 31.95 mph (51.42 km/h) |
| 35 mph (56.33 km/h) | 37.27 mph (59.99 km/h) |
| 40 mph (64.37 km/h) | 42.6 mph (68.56 km/h) |
| 45 mph (72.42 km/h) | 47.92 mph (77.13 km/h) |
| 50 mph (80.47 km/h) | 53.25 mph (85.7 km/h) |
| 55 mph (88.51 km/h) | 58.57 mph (94.27 km/h) |
| 60 mph (96.56 km/h) | 63.9 mph (102.84 km/h) |
| 65 mph (104.61 km/h) | 69.22 mph (111.41 km/h) |
| 70 mph (112.65 km/h) | 74.55 mph (119.98 km/h) |
| 75 mph (120.7 km/h) | 79.87 mph (128.55 km/h) |
| 80 mph (128.75 km/h) | 85.2 mph (137.12 km/h) |
| 85 mph (136.79 km/h) | 90.52 mph (145.68 km/h) |
| 90 mph (144.84 km/h) | 95.85 mph (154.25 km/h) |
| 95 mph (152.89 km/h) | 101.17 mph (162.82 km/h) |
| 100 mph (160.93 km/h) | 106.5 mph (171.39 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
