265/40R21 vs 285/35R22Tire Size Comparison

Safe

The 1.7% diameter difference is within the accepted 3% tolerance.

265/40R21745mm dia285/35R22758mm dia+6.4mm

Comparison Details

Overall Diameter745.4 vs 758.3 mm (+12.9 mm)
Diameter Difference+1.73%
Section Width265 vs 285 mm (+20 mm)
Sidewall Height106.0 vs 99.8 mm (-6.2 mm)
Circumference2341.7 vs 2382.3 mm
Clearance Change+6.4 mm
Speedometer Error+1.73%
Revs/Mile687 vs 676

Speedometer Correction

When switching from 265/40R21 to 285/35R22, 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/h50.9 km/h+0.9 km/h
60 km/h61.0 km/h+1.0 km/h
70 km/h71.2 km/h+1.2 km/h
80 km/h81.4 km/h+1.4 km/h
90 km/h91.6 km/h+1.6 km/h
100 km/h101.7 km/h+1.7 km/h
110 km/h111.9 km/h+1.9 km/h
120 km/h122.1 km/h+2.1 km/h
130 km/h132.2 km/h+2.2 km/h

Individual Tire Size Details

Practical Guidance

Switching from 265/40R21 to 285/35R22 is within the industry-accepted 3% diameter tolerance. Your speedometer, ABS, and traction control should function normally. Note: these sizes require different rim diameters (21" vs 22"), 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 1.73%, width changes by 20mm.

Speedometer error will be 1.73%. At an indicated 100 km/h, actual speed is about 101.7 km/h.

Ground clearance changes by +6.4mm per side.