255/45R20 vs 265/45R20Tire Size Comparison

Safe

The 1.2% diameter difference is within the accepted 3% tolerance.

255/45R20738mm dia265/45R20747mm dia+4.5mm

Comparison Details

Overall Diameter737.5 vs 746.5 mm (+9.0 mm)
Diameter Difference+1.22%
Section Width255 vs 265 mm (+10 mm)
Sidewall Height114.8 vs 119.3 mm (+4.5 mm)
Circumference2316.9 vs 2345.2 mm
Clearance Change+4.5 mm
Speedometer Error+1.22%
Revs/Mile695 vs 686

Speedometer Correction

When switching from 255/45R20 to 265/45R20, your speedometer will differ from actual speed.

SpeedometerActual SpeedDifference
30 km/h30.4 km/h+0.4 km/h
40 km/h40.5 km/h+0.5 km/h
50 km/h50.6 km/h+0.6 km/h
60 km/h60.7 km/h+0.7 km/h
70 km/h70.9 km/h+0.9 km/h
80 km/h81.0 km/h+1.0 km/h
90 km/h91.1 km/h+1.1 km/h
100 km/h101.2 km/h+1.2 km/h
110 km/h111.3 km/h+1.3 km/h
120 km/h121.5 km/h+1.5 km/h
130 km/h131.6 km/h+1.6 km/h

Vehicles Using These Sizes

Vehicles with 255/45R20

2025 Acura RDXA-Spec2024 Acura RDXA-Spec2023 Acura RDXA-Spec2022 Acura RDXA-Spec2021 Acura RDXA-Spec2020 Acura RDXA-Spec2025 Audi Q5Prestige 45 TFSI quattro2024 Audi Q5Prestige 45 TFSI quattro2021 Audi Q5Prestige 45 TFSI quattro2020 Audi Q5Prestige 45 TFSI quattro2024 Hyundai Santa FeCalligraphy2023 Hyundai Santa FeCalligraphy2025 Mitsubishi OutlanderSEL

Individual Tire Size Details

255/45R20
Full specifications, compatible vehicles, and alternatives
265/45R20
Full specifications, compatible vehicles, and alternatives

Practical Guidance

Switching from 255/45R20 to 265/45R20 is within the industry-accepted 3% diameter tolerance. Your speedometer, ABS, and traction control should function normally. Both sizes fit the same 20-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 1.22%, width changes by 10mm.

Speedometer error will be 1.22%. At an indicated 100 km/h, actual speed is about 101.2 km/h.

Ground clearance changes by +4.5mm per side.