255/50R20 vs 275/50R20Tire Size Comparison

Safe

The 2.6% diameter difference is within the accepted 3% tolerance.

255/50R20763mm dia275/50R20783mm dia+10.0mm

Comparison Details

Overall Diameter763.0 vs 783.0 mm (+20.0 mm)
Diameter Difference+2.62%
Section Width255 vs 275 mm (+20 mm)
Sidewall Height127.5 vs 137.5 mm (+10.0 mm)
Circumference2397.0 vs 2459.9 mm
Clearance Change+10.0 mm
Speedometer Error+2.62%
Revs/Mile671 vs 654

Speedometer Correction

When switching from 255/50R20 to 275/50R20, your speedometer will differ from actual speed.

SpeedometerActual SpeedDifference
30 km/h30.8 km/h+0.8 km/h
40 km/h41.0 km/h+1.0 km/h
50 km/h51.3 km/h+1.3 km/h
60 km/h61.6 km/h+1.6 km/h
70 km/h71.8 km/h+1.8 km/h
80 km/h82.1 km/h+2.1 km/h
90 km/h92.4 km/h+2.4 km/h
100 km/h102.6 km/h+2.6 km/h
110 km/h112.9 km/h+2.9 km/h
120 km/h123.1 km/h+3.1 km/h
130 km/h133.4 km/h+3.4 km/h

Vehicles Using These Sizes

Vehicles with 255/50R20

Individual Tire Size Details

Practical Guidance

Switching from 255/50R20 to 275/50R20 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 2.62%, width changes by 20mm.

Speedometer error will be 2.62%. At an indicated 100 km/h, actual speed is about 102.6 km/h.

Ground clearance changes by +10.0mm per side.