Question 1

What is the diameter of a 275/45 R21 tire?

Accepted Answer

A 275/45 R21 tire has a nominal overall diameter of 781 mm (30.7 inches), a sidewall height of 124 mm and a rolling circumference of 2453 mm. These are nominal figures calculated from the size marking; actual dimensions vary by manufacturer, load and wear.

Question 2

What do the numbers in 275/45 R21 mean?

Accepted Answer

275 is the nominal section width in millimetres. 45 is the sidewall height expressed as a percentage of that width, giving a 124 mm sidewall. R denotes radial construction, and 21 is the wheel bead-seat diameter in inches — which is not the overall tire diameter.

Question 3

Which vehicles use 275/45 R21 tires?

Accepted Answer

The catalogue records this size on 20 vehicle configurations, including 2019 Mercedes-Benz GLE-Class 3 Petrol Turbo Automatic 9-speed 4WD, 2019 Mercedes-Benz GLE-Class 5.5 Petrol Turbo Automatic 7-speed 4WD, 2018 Mercedes-Benz GLE-Class 3.5 Petrol Automatic 7-speed 4WD, 2018 Mercedes-Benz GLE-Class 3.5 Petrol Automatic 7-speed RWD, 2018 Mercedes-Benz GLE-Class 3 Petrol Turbo Automatic 9-speed 4WD. Always confirm the size against the vehicle placard before fitting.

Nominal section width	275 mm
Sidewall-to-width ratio	45%
Sidewall height	124 mm
Construction	R — radial
Wheel bead-seat diameter	21 inches
Overall diameter	781 mm (30.7 in)
Rolling circumference	2453 mm

275/45 R21 tire dimensions

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What 275/45 R21 means

Vehicles with 275/45 R21 tires