235/55R18 vs 255/50R19Tire Size Comparison
The 3.1% diameter difference exceeds 3% and may affect speedometer accuracy.
Comparison Details
Speedometer Correction
When switching from 235/55R18 to 255/50R19, your speedometer will differ from actual speed.
| Speedometer | Actual Speed | Difference |
|---|---|---|
| 30 km/h | 30.9 km/h | +0.9 km/h |
| 40 km/h | 41.2 km/h | +1.2 km/h |
| 50 km/h | 51.5 km/h | +1.5 km/h |
| 60 km/h | 61.8 km/h | +1.8 km/h |
| 70 km/h | 72.1 km/h | +2.1 km/h |
| 80 km/h | 82.4 km/h | +2.4 km/h |
| 90 km/h | 92.8 km/h | +2.8 km/h |
| 100 km/h | 103.1 km/h | +3.1 km/h |
| 110 km/h | 113.4 km/h | +3.4 km/h |
| 120 km/h | 123.7 km/h | +3.7 km/h |
| 130 km/h | 134.0 km/h | +4.0 km/h |
Vehicles Using These Sizes
Vehicles with 235/55R18
Vehicles with 255/50R19
Individual Tire Size Details
Practical Guidance
The 3.1% diameter difference between 235/55R18 and 255/50R19 exceeds the standard 3% tolerance. While physically possible, this change will cause noticeable speedometer error and may affect ABS and traction control calibration. Consult a tire professional before making this switch.
The 3% diameter tolerance is a widely accepted industry guideline referenced by the ETRTO and most vehicle manufacturers. When in doubt, consult your vehicle's owner's manual or a qualified tire professional. For U.S. tire safety standards and recalls, see the NHTSA Tire Safety page.
Frequently Asked Questions
Use Caution. The overall diameter differs by 3.06%, width changes by 20mm.
Speedometer error will be 3.06%. At an indicated 100 km/h, actual speed is about 103.1 km/h.
Ground clearance changes by +10.9mm per side.