Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 255/30-21 | 325/30-21 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 27.02 (686.4) | 28.68 (728.4) | 1.65 (42) 6.1% |
| Width inches (mm) | 10.04 (255) | 12.8 (325) | 2.76 (70) 27.5% |
| Circum. inches (mm) | 84.9 (2156.39) | 90.09 (2288.34) | 5.19 (131.95) 6.1% |
| Sidewall Height inches (mm) | 3.01 (76.5) | 3.84 (97.5) | 0.83 (21) 27.5% |
| Revolutions per mile (km) | 746.31 (463.74) | 703.28 (437) | -43.03 (-26.74) -5.8% |
325/30-21 Tires
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 21.22 mph (34.16 km/h) |
| 25 mph (40.23 km/h) | 26.53 mph (42.7 km/h) |
| 30 mph (48.28 km/h) | 31.84 mph (51.23 km/h) |
| 35 mph (56.33 km/h) | 37.14 mph (59.77 km/h) |
| 40 mph (64.37 km/h) | 42.45 mph (68.31 km/h) |
| 45 mph (72.42 km/h) | 47.75 mph (76.85 km/h) |
| 50 mph (80.47 km/h) | 53.06 mph (85.39 km/h) |
| 55 mph (88.51 km/h) | 58.37 mph (93.93 km/h) |
| 60 mph (96.56 km/h) | 63.67 mph (102.47 km/h) |
| 65 mph (104.61 km/h) | 68.98 mph (111.01 km/h) |
| 70 mph (112.65 km/h) | 74.28 mph (119.55 km/h) |
| 75 mph (120.7 km/h) | 79.59 mph (128.09 km/h) |
| 80 mph (128.75 km/h) | 84.9 mph (136.63 km/h) |
| 85 mph (136.79 km/h) | 90.2 mph (145.16 km/h) |
| 90 mph (144.84 km/h) | 95.51 mph (153.7 km/h) |
| 95 mph (152.89 km/h) | 100.81 mph (162.24 km/h) |
| 100 mph (160.93 km/h) | 106.12 mph (170.78 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1790 | 2079 | 2239 | 2338 | 2445 | 2521 | 2605 | 2704 | 2841 | 2978 | 3130 | 3252 | 3473 | 3717 | 3907 | 4029 | 4097 | 4349 | 4699 | 5461 |
Better Fuel Economy Factory Ratios Increased Power
