235/45R17 vs 245/45R17 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 | 235/45R17 | 245/45R17 | Difference |
|---|---|---|---|
| Overall Diameter | 643.3 mm (25.3") | 652.3 mm (25.7") | +9 mm |
| Section Width | 235 mm (9.3") | 245 mm (9.6") | +10 mm |
| Sidewall Height | 105.8 mm | 110.3 mm | +4.5 mm |
| Circumference | 2021 mm | 2049.3 mm | +28.3 mm |
| Revolutions/Mile | 796 | 785 | -11 |
| Aspect Ratio | 45% | 45% | 0% |
| Rim Diameter | 17" | 17" | 0" |
Key Impact Summary
Speedometer Correction Table
When switching from 235/45R17 to 245/45R17, your speedometer will under-read. Here is the correction at common speeds:
| Speedometer Shows | Actual Speed (mph) | Difference |
|---|---|---|
| 30 mph | 30.4 mph | +0.4 mph |
| 40 mph | 40.6 mph | +0.6 mph |
| 50 mph | 50.7 mph | +0.7 mph |
| 60 mph | 60.8 mph | +0.8 mph |
| 70 mph | 71 mph | +1 mph |
| 80 mph | 81.1 mph | +1.1 mph |
| 90 mph | 91.3 mph | +1.3 mph |
| 100 mph | 101.4 mph | +1.4 mph |
| 110 mph | 111.5 mph | +1.5 mph |
| 120 mph | 121.7 mph | +1.7 mph |
What This Swap Means
Wider tires (245/45R17): 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 4.5mm 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 4.5mm, providing slightly better approach angles for off-road driving and speed bump clearance.