Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 255/30-21 | 285/30-21 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 27.02 (686.4) | 27.73 (704.4) | 0.71 (18) 2.6% |
| Width inches (mm) | 10.04 (255) | 11.22 (285) | 1.18 (30) 11.8% |
| Circum. inches (mm) | 84.9 (2156.39) | 87.12 (2212.94) | 2.23 (56.55) 2.6% |
| Sidewall Height inches (mm) | 3.01 (76.5) | 3.37 (85.5) | 0.35 (9) 11.8% |
| Revolutions per mile (km) | 746.31 (463.74) | 727.24 (451.89) | -19.07 (-11.85) -2.6% |
285/30-21 Tires
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 20.52 mph (33.03 km/h) |
| 25 mph (40.23 km/h) | 25.66 mph (41.29 km/h) |
| 30 mph (48.28 km/h) | 30.79 mph (49.55 km/h) |
| 35 mph (56.33 km/h) | 35.92 mph (57.8 km/h) |
| 40 mph (64.37 km/h) | 41.05 mph (66.06 km/h) |
| 45 mph (72.42 km/h) | 46.18 mph (74.32 km/h) |
| 50 mph (80.47 km/h) | 51.31 mph (82.58 km/h) |
| 55 mph (88.51 km/h) | 56.44 mph (90.84 km/h) |
| 60 mph (96.56 km/h) | 61.57 mph (99.09 km/h) |
| 65 mph (104.61 km/h) | 66.7 mph (107.35 km/h) |
| 70 mph (112.65 km/h) | 71.84 mph (115.61 km/h) |
| 75 mph (120.7 km/h) | 76.97 mph (123.87 km/h) |
| 80 mph (128.75 km/h) | 82.1 mph (132.12 km/h) |
| 85 mph (136.79 km/h) | 87.23 mph (140.38 km/h) |
| 90 mph (144.84 km/h) | 92.36 mph (148.64 km/h) |
| 95 mph (152.89 km/h) | 97.49 mph (156.9 km/h) |
| 100 mph (160.93 km/h) | 102.62 mph (165.16 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1851 | 2150 | 2315 | 2418 | 2528 | 2607 | 2693 | 2796 | 2937 | 3079 | 3237 | 3363 | 3591 | 3843 | 4040 | 4166 | 4237 | 4497 | 4859 | 5647 |
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