255/65R18 vs 275/65R18Tire Size Comparison
The 3.3% diameter difference exceeds 3% and may affect speedometer accuracy.
Comparison Details
Speedometer Correction
When switching from 255/65R18 to 275/65R18, your speedometer will differ from actual speed.
| Speedometer | Actual Speed | Difference |
|---|---|---|
| 30 km/h | 31.0 km/h | +1.0 km/h |
| 40 km/h | 41.3 km/h | +1.3 km/h |
| 50 km/h | 51.6 km/h | +1.6 km/h |
| 60 km/h | 62.0 km/h | +2.0 km/h |
| 70 km/h | 72.3 km/h | +2.3 km/h |
| 80 km/h | 82.6 km/h | +2.6 km/h |
| 90 km/h | 93.0 km/h | +3.0 km/h |
| 100 km/h | 103.3 km/h | +3.3 km/h |
| 110 km/h | 113.6 km/h | +3.6 km/h |
| 120 km/h | 124.0 km/h | +4.0 km/h |
| 130 km/h | 134.3 km/h | +4.3 km/h |
Vehicles Using These Sizes
Vehicles with 255/65R18
Vehicles with 275/65R18
Individual Tire Size Details
Practical Guidance
The 3.3% diameter difference between 255/65R18 and 275/65R18 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 3.30%, width changes by 20mm.
Speedometer error will be 3.30%. At an indicated 100 km/h, actual speed is about 103.3 km/h.
Ground clearance changes by +13.0mm per side.