275/70R17 vs 275/65R18Tire Size Comparison
The 0.3% diameter difference is within the accepted 3% tolerance.
Comparison Details
Speedometer Correction
When switching from 275/70R17 to 275/65R18, your speedometer will differ from actual speed.
| Speedometer | Actual Speed | Difference |
|---|---|---|
| 30 km/h | 29.9 km/h | -0.1 km/h |
| 40 km/h | 39.9 km/h | -0.1 km/h |
| 50 km/h | 49.9 km/h | -0.1 km/h |
| 60 km/h | 59.8 km/h | -0.2 km/h |
| 70 km/h | 69.8 km/h | -0.2 km/h |
| 80 km/h | 79.8 km/h | -0.2 km/h |
| 90 km/h | 89.8 km/h | -0.2 km/h |
| 100 km/h | 99.7 km/h | -0.3 km/h |
| 110 km/h | 109.7 km/h | -0.3 km/h |
| 120 km/h | 119.7 km/h | -0.3 km/h |
| 130 km/h | 129.7 km/h | -0.3 km/h |
Vehicles Using These Sizes
Vehicles with 275/65R18
Individual Tire Size Details
Practical Guidance
Switching from 275/70R17 to 275/65R18 is within the industry-accepted 3% diameter tolerance. Your speedometer, ABS, and traction control should function normally. Note: these sizes require different rim diameters (17" vs 18"), so you will need different wheels.
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
Safe. The overall diameter differs by -0.26%, width changes by 0mm.
Speedometer error will be -0.26%. At an indicated 100 km/h, actual speed is about 99.7 km/h.
Ground clearance changes by -1.0mm per side.