225/60R18 vs 235/60R18Tire Size Comparison

Safe

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

225/60R18727mm dia235/60R18739mm dia+6.0mm

Comparison Details

Overall Diameter727.2 vs 739.2 mm (+12.0 mm)
Diameter Difference+1.65%
Section Width225 vs 235 mm (+10 mm)
Sidewall Height135.0 vs 141.0 mm (+6.0 mm)
Circumference2284.6 vs 2322.3 mm
Clearance Change+6.0 mm
Speedometer Error+1.65%
Revs/Mile704 vs 693

Speedometer Correction

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

SpeedometerActual SpeedDifference
30 km/h30.5 km/h+0.5 km/h
40 km/h40.7 km/h+0.7 km/h
50 km/h50.8 km/h+0.8 km/h
60 km/h61.0 km/h+1.0 km/h
70 km/h71.2 km/h+1.2 km/h
80 km/h81.3 km/h+1.3 km/h
90 km/h91.5 km/h+1.5 km/h
100 km/h101.7 km/h+1.7 km/h
110 km/h111.8 km/h+1.8 km/h
120 km/h122.0 km/h+2.0 km/h
130 km/h132.1 km/h+2.1 km/h

Vehicles Using These Sizes

Vehicles with 225/60R18

Vehicles with 235/60R18

Individual Tire Size Details

Practical Guidance

Switching from 225/60R18 to 235/60R18 is within the industry-accepted 3% diameter tolerance. Your speedometer, ABS, and traction control should function normally. Both sizes fit the same 18-inch rim, so no wheel change is needed.

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 1.65%, width changes by 10mm.

Speedometer error will be 1.65%. At an indicated 100 km/h, actual speed is about 101.7 km/h.

Ground clearance changes by +6.0mm per side.