Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 255/40-21 | 245/40-21 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 29.03 (737.4) | 28.72 (729.4) | -0.31 (-8) -1.1% |
| Width inches (mm) | 10.04 (255) | 9.65 (245) | -0.39 (-10) -3.9% |
| Circum. inches (mm) | 91.21 (2316.61) | 90.22 (2291.48) | -0.99 (-25.13) -1.1% |
| Sidewall Height inches (mm) | 4.02 (102) | 3.86 (98) | -0.16 (-4) -3.9% |
| Revolutions per mile (km) | 694.7 (431.66) | 702.32 (436.4) | 7.62 (4.73) 1.1% |
245/40-21 Tires
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 19.78 mph (31.84 km/h) |
| 25 mph (40.23 km/h) | 24.73 mph (39.8 km/h) |
| 30 mph (48.28 km/h) | 29.67 mph (47.76 km/h) |
| 35 mph (56.33 km/h) | 34.62 mph (55.72 km/h) |
| 40 mph (64.37 km/h) | 39.57 mph (63.68 km/h) |
| 45 mph (72.42 km/h) | 44.51 mph (71.63 km/h) |
| 50 mph (80.47 km/h) | 49.46 mph (79.59 km/h) |
| 55 mph (88.51 km/h) | 54.4 mph (87.55 km/h) |
| 60 mph (96.56 km/h) | 59.35 mph (95.51 km/h) |
| 65 mph (104.61 km/h) | 64.29 mph (103.47 km/h) |
| 70 mph (112.65 km/h) | 69.24 mph (111.43 km/h) |
| 75 mph (120.7 km/h) | 74.19 mph (119.39 km/h) |
| 80 mph (128.75 km/h) | 79.13 mph (127.35 km/h) |
| 85 mph (136.79 km/h) | 84.08 mph (135.31 km/h) |
| 90 mph (144.84 km/h) | 89.02 mph (143.27 km/h) |
| 95 mph (152.89 km/h) | 93.97 mph (151.23 km/h) |
| 100 mph (160.93 km/h) | 98.92 mph (159.19 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1787 | 2076 | 2236 | 2335 | 2441 | 2517 | 2601 | 2700 | 2837 | 2974 | 3126 | 3247 | 3468 | 3711 | 3902 | 4023 | 4092 | 4343 | 4693 | 5453 |
Better Fuel Economy Factory Ratios Increased Power
