265/40R21 vs 275/40R21Tire Size Comparison

Safe

The 1.1% diameter difference is within the accepted 3% tolerance.

265/40R21745mm dia275/40R21753mm dia+4.0mm

Comparison Details

Overall Diameter745.4 vs 753.4 mm (+8.0 mm)
Diameter Difference+1.07%
Section Width265 vs 275 mm (+10 mm)
Sidewall Height106.0 vs 110.0 mm (+4.0 mm)
Circumference2341.7 vs 2366.9 mm
Clearance Change+4.0 mm
Speedometer Error+1.07%
Revs/Mile687 vs 680

Speedometer Correction

When switching from 265/40R21 to 275/40R21, your speedometer will differ from actual speed.

SpeedometerActual SpeedDifference
30 km/h30.3 km/h+0.3 km/h
40 km/h40.4 km/h+0.4 km/h
50 km/h50.5 km/h+0.5 km/h
60 km/h60.6 km/h+0.6 km/h
70 km/h70.8 km/h+0.8 km/h
80 km/h80.9 km/h+0.9 km/h
90 km/h91.0 km/h+1.0 km/h
100 km/h101.1 km/h+1.1 km/h
110 km/h111.2 km/h+1.2 km/h
120 km/h121.3 km/h+1.3 km/h
130 km/h131.4 km/h+1.4 km/h

Vehicles Using These Sizes

Vehicles with 275/40R21

2025 Volvo XC90Ultimate B6 AWD2024 Volvo XC90Ultimate B6 AWD

Individual Tire Size Details

265/40R21
Full specifications, compatible vehicles, and alternatives
275/40R21
Full specifications, compatible vehicles, and alternatives

Practical Guidance

Switching from 265/40R21 to 275/40R21 is within the industry-accepted 3% diameter tolerance. Your speedometer, ABS, and traction control should function normally. Both sizes fit the same 21-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 1.07%, width changes by 10mm.

Speedometer error will be 1.07%. At an indicated 100 km/h, actual speed is about 101.1 km/h.

Ground clearance changes by +4.0mm per side.