265/60R18 vs 255/65R17Tire Size Comparison

Safe

The 1.5% diameter difference is within the accepted 3% tolerance.

265/60R18775mm dia255/65R17763mm dia-6.0mm

Comparison Details

Overall Diameter775.2 vs 763.3 mm (-11.9 mm)
Diameter Difference-1.54%
Section Width265 vs 255 mm (-10 mm)
Sidewall Height159.0 vs 165.8 mm (+6.8 mm)
Circumference2435.4 vs 2398.0 mm
Clearance Change-6.0 mm
Speedometer Error-1.54%
Revs/Mile661 vs 671

Speedometer Correction

When switching from 265/60R18 to 255/65R17, your speedometer will differ from actual speed.

SpeedometerActual SpeedDifference
30 km/h29.5 km/h-0.5 km/h
40 km/h39.4 km/h-0.6 km/h
50 km/h49.2 km/h-0.8 km/h
60 km/h59.1 km/h-0.9 km/h
70 km/h68.9 km/h-1.1 km/h
80 km/h78.8 km/h-1.2 km/h
90 km/h88.6 km/h-1.4 km/h
100 km/h98.5 km/h-1.5 km/h
110 km/h108.3 km/h-1.7 km/h
120 km/h118.2 km/h-1.8 km/h
130 km/h128.0 km/h-2.0 km/h

Vehicles Using These Sizes

Vehicles with 265/60R18

Vehicles with 255/65R17

Individual Tire Size Details

Practical Guidance

Switching from 265/60R18 to 255/65R17 is within the industry-accepted 3% diameter tolerance. Your speedometer, ABS, and traction control should function normally. Note: these sizes require different rim diameters (18" vs 17"), 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 -1.54%, width changes by -10mm.

Speedometer error will be -1.54%. At an indicated 100 km/h, actual speed is about 98.5 km/h.

Ground clearance changes by -6.0mm per side.