Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 245/40-21 | 255/40-21 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 28.72 (729.4) | 29.03 (737.4) | 0.31 (8) 1.1% |
| Width inches (mm) | 9.65 (245) | 10.04 (255) | 0.39 (10) 4.1% |
| Circum. inches (mm) | 90.22 (2291.48) | 91.21 (2316.61) | 0.99 (25.13) 1.1% |
| Sidewall Height inches (mm) | 3.86 (98) | 4.02 (102) | 0.16 (4) 4.1% |
| Revolutions per mile (km) | 702.32 (436.4) | 694.7 (431.66) | -7.62 (-4.73) -1.1% |
255/40-21 Tires
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 20.22 mph (32.54 km/h) |
| 25 mph (40.23 km/h) | 25.27 mph (40.67 km/h) |
| 30 mph (48.28 km/h) | 30.33 mph (48.81 km/h) |
| 35 mph (56.33 km/h) | 35.38 mph (56.94 km/h) |
| 40 mph (64.37 km/h) | 40.44 mph (65.08 km/h) |
| 45 mph (72.42 km/h) | 45.49 mph (73.21 km/h) |
| 50 mph (80.47 km/h) | 50.55 mph (81.35 km/h) |
| 55 mph (88.51 km/h) | 55.6 mph (89.48 km/h) |
| 60 mph (96.56 km/h) | 60.66 mph (97.62 km/h) |
| 65 mph (104.61 km/h) | 65.71 mph (105.75 km/h) |
| 70 mph (112.65 km/h) | 70.77 mph (113.89 km/h) |
| 75 mph (120.7 km/h) | 75.82 mph (122.02 km/h) |
| 80 mph (128.75 km/h) | 80.88 mph (130.16 km/h) |
| 85 mph (136.79 km/h) | 85.93 mph (138.29 km/h) |
| 90 mph (144.84 km/h) | 90.99 mph (146.43 km/h) |
| 95 mph (152.89 km/h) | 96.04 mph (154.56 km/h) |
| 100 mph (160.93 km/h) | 101.1 mph (162.7 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
