255/65R17 vs 265/60R18Tire Size Comparison

Safe

The 1.6% diameter difference is within the accepted 3% tolerance.

255/65R17763mm dia265/60R18775mm dia+6.0mm

Comparison Details

Overall Diameter763.3 vs 775.2 mm (+11.9 mm)
Diameter Difference+1.56%
Section Width255 vs 265 mm (+10 mm)
Sidewall Height165.8 vs 159.0 mm (-6.8 mm)
Circumference2398.0 vs 2435.4 mm
Clearance Change+6.0 mm
Speedometer Error+1.56%
Revs/Mile671 vs 661

Speedometer Correction

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

SpeedometerActual SpeedDifference
30 km/h30.5 km/h+0.5 km/h
40 km/h40.6 km/h+0.6 km/h
50 km/h50.8 km/h+0.8 km/h
60 km/h60.9 km/h+0.9 km/h
70 km/h71.1 km/h+1.1 km/h
80 km/h81.2 km/h+1.2 km/h
90 km/h91.4 km/h+1.4 km/h
100 km/h101.6 km/h+1.6 km/h
110 km/h111.7 km/h+1.7 km/h
120 km/h121.9 km/h+1.9 km/h
130 km/h132.0 km/h+2.0 km/h

Vehicles Using These Sizes

Vehicles with 255/65R17

Vehicles with 265/60R18

Individual Tire Size Details

Practical Guidance

Switching from 255/65R17 to 265/60R18 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 1.56%, width changes by 10mm.

Speedometer error will be 1.56%. At an indicated 100 km/h, actual speed is about 101.6 km/h.

Ground clearance changes by +6.0mm per side.