225/65R17 vs 235/60R18Tire Size Comparison

Safe

The 2.1% diameter difference is within the accepted 3% tolerance.

225/65R17724mm dia235/60R18739mm dia+7.5mm

Comparison Details

Overall Diameter724.3 vs 739.2 mm (+14.9 mm)
Diameter Difference+2.06%
Section Width225 vs 235 mm (+10 mm)
Sidewall Height146.3 vs 141.0 mm (-5.3 mm)
Circumference2275.5 vs 2322.3 mm
Clearance Change+7.5 mm
Speedometer Error+2.06%
Revs/Mile707 vs 693

Speedometer Correction

When switching from 225/65R17 to 235/60R18, your speedometer will differ from actual speed.

SpeedometerActual SpeedDifference
30 km/h30.6 km/h+0.6 km/h
40 km/h40.8 km/h+0.8 km/h
50 km/h51.0 km/h+1.0 km/h
60 km/h61.2 km/h+1.2 km/h
70 km/h71.4 km/h+1.4 km/h
80 km/h81.6 km/h+1.6 km/h
90 km/h91.9 km/h+1.9 km/h
100 km/h102.1 km/h+2.1 km/h
110 km/h112.3 km/h+2.3 km/h
120 km/h122.5 km/h+2.5 km/h
130 km/h132.7 km/h+2.7 km/h

Vehicles Using These Sizes

Vehicles with 225/65R17

Vehicles with 235/60R18

Individual Tire Size Details

Practical Guidance

Switching from 225/65R17 to 235/60R18 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 2.06%, width changes by 10mm.

Speedometer error will be 2.06%. At an indicated 100 km/h, actual speed is about 102.1 km/h.

Ground clearance changes by +7.5mm per side.