Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 325/30-21 | 315/35-21 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 28.68 (728.4) | 29.68 (753.9) | 1 (25.5) 3.5% |
| Width inches (mm) | 12.8 (325) | 12.4 (315) | -0.39 (-10) -3.1% |
| Circum. inches (mm) | 90.09 (2288.34) | 93.25 (2368.45) | 3.15 (80.11) 3.5% |
| Sidewall Height inches (mm) | 3.84 (97.5) | 4.34 (110.25) | 0.5 (12.75) 13.1% |
| Revolutions per mile (km) | 703.28 (437) | 679.49 (422.22) | -23.79 (-14.78) -3.4% |
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 20.7 mph (33.31 km/h) |
| 25 mph (40.23 km/h) | 25.88 mph (41.64 km/h) |
| 30 mph (48.28 km/h) | 31.05 mph (49.97 km/h) |
| 35 mph (56.33 km/h) | 36.23 mph (58.3 km/h) |
| 40 mph (64.37 km/h) | 41.4 mph (66.63 km/h) |
| 45 mph (72.42 km/h) | 46.58 mph (74.96 km/h) |
| 50 mph (80.47 km/h) | 51.75 mph (83.28 km/h) |
| 55 mph (88.51 km/h) | 56.93 mph (91.61 km/h) |
| 60 mph (96.56 km/h) | 62.1 mph (99.94 km/h) |
| 65 mph (104.61 km/h) | 67.28 mph (108.27 km/h) |
| 70 mph (112.65 km/h) | 72.45 mph (116.6 km/h) |
| 75 mph (120.7 km/h) | 77.63 mph (124.93 km/h) |
| 80 mph (128.75 km/h) | 82.8 mph (133.25 km/h) |
| 85 mph (136.79 km/h) | 87.98 mph (141.58 km/h) |
| 90 mph (144.84 km/h) | 93.15 mph (149.91 km/h) |
| 95 mph (152.89 km/h) | 98.33 mph (158.24 km/h) |
| 100 mph (160.93 km/h) | 103.5 mph (166.57 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1729 | 2009 | 2163 | 2259 | 2362 | 2436 | 2517 | 2612 | 2745 | 2877 | 3024 | 3142 | 3355 | 3591 | 3775 | 3892 | 3959 | 4202 | 4540 | 5276 |
Better Fuel Economy Factory Ratios Increased Power
