225/55R18 vs 235/55R18 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 | 225/55R18 | 235/55R18 | Difference |
|---|---|---|---|
| Overall Diameter | 704.7 mm (27.7") | 715.7 mm (28.2") | +11 mm |
| Section Width | 225 mm (8.9") | 235 mm (9.3") | +10 mm |
| Sidewall Height | 123.8 mm | 129.3 mm | +5.5 mm |
| Circumference | 2213.9 mm | 2248.4 mm | +34.5 mm |
| Revolutions/Mile | 727 | 716 | -11 |
| Aspect Ratio | 55% | 55% | 0% |
| Rim Diameter | 18" | 18" | 0" |
Key Impact Summary
Speedometer Correction Table
When switching from 225/55R18 to 235/55R18, your speedometer will under-read. Here is the correction at common speeds:
| Speedometer Shows | Actual Speed (mph) | Difference |
|---|---|---|
| 30 mph | 30.5 mph | +0.5 mph |
| 40 mph | 40.6 mph | +0.6 mph |
| 50 mph | 50.8 mph | +0.8 mph |
| 60 mph | 60.9 mph | +0.9 mph |
| 70 mph | 71.1 mph | +1.1 mph |
| 80 mph | 81.2 mph | +1.2 mph |
| 90 mph | 91.4 mph | +1.4 mph |
| 100 mph | 101.6 mph | +1.6 mph |
| 110 mph | 111.7 mph | +1.7 mph |
| 120 mph | 121.9 mph | +1.9 mph |
What This Swap Means
Wider tires (235/55R18): The 10mm 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 5.5mm 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 5.5mm, providing slightly better approach angles for off-road driving and speed bump clearance.