225/50R18 vs 235/50R18Tire Size Comparison

Safe

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

225/50R18682mm dia235/50R18692mm dia+5.0mm

Comparison Details

Overall Diameter682.2 vs 692.2 mm (+10.0 mm)
Diameter Difference+1.47%
Section Width225 vs 235 mm (+10 mm)
Sidewall Height112.5 vs 117.5 mm (+5.0 mm)
Circumference2143.2 vs 2174.6 mm
Clearance Change+5.0 mm
Speedometer Error+1.47%
Revs/Mile751 vs 740

Speedometer Correction

When switching from 225/50R18 to 235/50R18, your speedometer will differ from actual speed.

SpeedometerActual SpeedDifference
30 km/h30.4 km/h+0.4 km/h
40 km/h40.6 km/h+0.6 km/h
50 km/h50.7 km/h+0.7 km/h
60 km/h60.9 km/h+0.9 km/h
70 km/h71.0 km/h+1.0 km/h
80 km/h81.2 km/h+1.2 km/h
90 km/h91.3 km/h+1.3 km/h
100 km/h101.5 km/h+1.5 km/h
110 km/h111.6 km/h+1.6 km/h
120 km/h121.8 km/h+1.8 km/h
130 km/h131.9 km/h+1.9 km/h

Vehicles Using These Sizes

Vehicles with 225/50R18

Vehicles with 235/50R18

Individual Tire Size Details

Practical Guidance

Switching from 225/50R18 to 235/50R18 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 1.47%, width changes by 10mm.

Speedometer error will be 1.47%. At an indicated 100 km/h, actual speed is about 101.5 km/h.

Ground clearance changes by +5.0mm per side.