235/55R19 vs 255/45R19 Side-by-side tire size comparison with specs and compatibility
This tire swap is between 3-5% diameter difference. Check for fender clearance and be aware of speedometer error. May require recalibration.
Full Specifications Comparison
| Specification | 235/55R19 | 255/45R19 | Difference |
|---|---|---|---|
| Overall Diameter | 741.1 mm (29.2") | 712.1 mm (28") | -29 mm |
| Section Width | 235 mm (9.3") | 255 mm (10") | +20 mm |
| Sidewall Height | 129.3 mm | 114.8 mm | -14.5 mm |
| Circumference | 2328.2 mm | 2237.1 mm | -91.1 mm |
| Revolutions/Mile | 691 | 719 | +28 |
| Aspect Ratio | 55% | 45% | -10% |
| Rim Diameter | 19" | 19" | 0" |
Key Impact Summary
Speedometer Correction Table
When switching from 235/55R19 to 255/45R19, your speedometer will over-read. Here is the correction at common speeds:
| Speedometer Shows | Actual Speed (mph) | Difference |
|---|---|---|
| 30 mph | 28.8 mph | -1.2 mph |
| 40 mph | 38.4 mph | -1.6 mph |
| 50 mph | 48 mph | -2 mph |
| 60 mph | 57.7 mph | -2.3 mph |
| 70 mph | 67.3 mph | -2.7 mph |
| 80 mph | 76.9 mph | -3.1 mph |
| 90 mph | 86.5 mph | -3.5 mph |
| 100 mph | 96.1 mph | -3.9 mph |
| 110 mph | 105.7 mph | -4.3 mph |
| 120 mph | 115.3 mph | -4.7 mph |
What This Swap Means
Wider tires (255/45R19): 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.
Shorter sidewall: The 14.5mm decrease in sidewall height improves steering response and cornering precision. However, ride quality becomes firmer and the wheels are more vulnerable to pothole damage. This is a common trade-off when upsizing wheels (plus-sizing).
Ground clearance: Decreases by 14.5mm, lowering the center of gravity slightly which can improve handling stability.