Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 275/40-21 | 305/40-21 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 29.66 (753.4) | 30.61 (777.4) | 0.94 (24) 3.2% |
| Width inches (mm) | 10.83 (275) | 12.01 (305) | 1.18 (30) 10.9% |
| Circum. inches (mm) | 93.18 (2366.88) | 96.15 (2442.27) | 2.97 (75.4) 3.2% |
| Sidewall Height inches (mm) | 4.33 (110) | 4.8 (122) | 0.47 (12) 10.9% |
| Revolutions per mile (km) | 679.94 (422.5) | 658.95 (409.45) | -20.99 (-13.04) -3.1% |
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 20.64 mph (33.21 km/h) |
| 25 mph (40.23 km/h) | 25.8 mph (41.52 km/h) |
| 30 mph (48.28 km/h) | 30.96 mph (49.82 km/h) |
| 35 mph (56.33 km/h) | 36.11 mph (58.12 km/h) |
| 40 mph (64.37 km/h) | 41.27 mph (66.42 km/h) |
| 45 mph (72.42 km/h) | 46.43 mph (74.73 km/h) |
| 50 mph (80.47 km/h) | 51.59 mph (83.03 km/h) |
| 55 mph (88.51 km/h) | 56.75 mph (91.33 km/h) |
| 60 mph (96.56 km/h) | 61.91 mph (99.64 km/h) |
| 65 mph (104.61 km/h) | 67.07 mph (107.94 km/h) |
| 70 mph (112.65 km/h) | 72.23 mph (116.24 km/h) |
| 75 mph (120.7 km/h) | 77.39 mph (124.55 km/h) |
| 80 mph (128.75 km/h) | 82.55 mph (132.85 km/h) |
| 85 mph (136.79 km/h) | 87.71 mph (141.15 km/h) |
| 90 mph (144.84 km/h) | 92.87 mph (149.46 km/h) |
| 95 mph (152.89 km/h) | 98.03 mph (157.76 km/h) |
| 100 mph (160.93 km/h) | 103.19 mph (166.06 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1677 | 1948 | 2098 | 2191 | 2291 | 2362 | 2440 | 2533 | 2662 | 2790 | 2933 | 3047 | 3254 | 3482 | 3661 | 3775 | 3839 | 4075 | 4403 | 5116 |
Better Fuel Economy Factory Ratios Increased Power
