255/50R20 vs 275/50R20 Side-by-side tire size comparison with specs and compatibility
This tire swap is within the safe 3% diameter threshold. It should not cause issues with speedometer accuracy, ABS, or traction control systems.
Full Specifications Comparison
| Specification | 255/50R20 | 275/50R20 | Difference |
|---|---|---|---|
| Overall Diameter | 763 mm (30") | 783 mm (30.8") | +20 mm |
| Section Width | 255 mm (10") | 275 mm (10.8") | +20 mm |
| Sidewall Height | 127.5 mm | 137.5 mm | +10 mm |
| Circumference | 2397 mm | 2459.9 mm | +62.9 mm |
| Revolutions/Mile | 671 | 654 | -17 |
| Aspect Ratio | 50% | 50% | 0% |
| Rim Diameter | 20" | 20" | 0" |
Key Impact Summary
Speedometer Correction Table
When switching from 255/50R20 to 275/50R20, your speedometer will under-read. Here is the correction at common speeds:
| Speedometer Shows | Actual Speed (mph) | Difference |
|---|---|---|
| 30 mph | 30.8 mph | +0.8 mph |
| 40 mph | 41 mph | +1 mph |
| 50 mph | 51.3 mph | +1.3 mph |
| 60 mph | 61.6 mph | +1.6 mph |
| 70 mph | 71.8 mph | +1.8 mph |
| 80 mph | 82.1 mph | +2.1 mph |
| 90 mph | 92.4 mph | +2.4 mph |
| 100 mph | 102.6 mph | +2.6 mph |
| 110 mph | 112.9 mph | +2.9 mph |
| 120 mph | 123.1 mph | +3.1 mph |
What This Swap Means
Wider tires (275/50R20): The 20mm wider contact patch provides better grip in dry conditions and improved cornering stability. However, wider tires increase rolling resistance slightly, which may affect fuel economy by 1-2%. They are also more susceptible to hydroplaning in wet conditions.
Taller sidewall: The 10.0mm increase in sidewall height provides a more comfortable ride by absorbing more road imperfections. Taller sidewalls also offer better protection against pothole damage to wheels. The trade-off is slightly less responsive steering feel.
Ground clearance: Increases by 10mm, providing slightly better approach angles for off-road driving and speed bump clearance.