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Tire size · 21-inch wheel · about 30.7x10.8R21

275/45R21 tire size

Overall diameter, nominal30.7 in

Estimate ±781 mm

A 275/45R21 tire is 30.7 in (781 mm) tall and 10.8 in (275 mm) wide on a 21-inch wheel, with a 4.9 in sidewall, and turns about 656 times a mile.

Stock on the Ford Explorer (2025) and Volkswagen Amarok (2023 and 2025), per their makers’ documents.

Width
10.8 in
Sidewall
4.9 in
Wheel
21 in
Revs per mile
656

01 / Dimensions

275/45R21 in inches and millimeters

What the size code works out to. A real tire of the size measures within about 1.5% of it, by brand, tread, wheel width and pressure.

275/45R21

Estimate ±
Overall diameter
30.7 in 781 mm30.3 to 31.2 in for real tires
Section width
10.8 in 275 mm
Sidewall height
4.9 in 124 mm
Wheel diameter
21 in 533 mm
Circumference
96.6 in 2,453 mm
Revolutions per mile
656 408 per km646 to 666

02 / Stock on

Vehicles that leave the factory on 275/45R21

Which configurations run it in which model years, printed the way each maker prints the size, and how it compares with the vehicle’s other stock sizes. A speedometer set for one of those reads off by the amount shown when you fit 275/45R21 instead.

  • Ford ExplorerMaker
    • 2025 · STprinted P275/45R21

    Ford Explorer model years on 275/45R21:

    Its other stock sizes

    • 255/65R18 (2025 · Active). 275/45R21 is 0.3 in shorter: with a speedometer set for 255/65R18 it reads 1.0% high, 59.4 mph at an indicated 60.
    • 255/55R20 (2025 · ST-Line; Platinum). 275/45R21 is 0.3 in shorter: with a speedometer set for 255/55R20 it reads 1.0% high, 59.4 mph at an indicated 60.
  • Volkswagen AmarokMaker
    • 2025 · Australia · Aventuraprinted 275/45R21
    • 2023 · Australia · Aventuraprinted 275/45R21

    Volkswagen Amarok model years on 275/45R21:

    Its other stock sizes

    • 255/70R17 (2023 and 2025 · Core, Life). 275/45R21 is 0.3 in shorter: with a speedometer set for 255/70R17 it reads 1.0% high, 59.4 mph at an indicated 60.
    • 255/65R18 (2023 and 2025 · Style; PanAmericana). 275/45R21 is 0.3 in shorter: with a speedometer set for 255/65R18 it reads 1.0% high, 59.4 mph at an indicated 60.

Documents last checked . How we read them and what the marks mean: how we source the numbers. A figure doesn’t match its document? Report a wrong number.

03 / Nearby sizes

Sizes either side of 275/45R21

The nearest common upsizes and the next sizes down on the same wheel, from the stock sizes we cover and the sizes owners usually step up to, and sizes about as tall on another wheel.

About as tall, other wheels

About as tall, other wheels, compared with 275/45R21
SizeTallinHeightvs 275/45R21Widthvs 275/45R21At an indicated 60true mphCompare
275/50R2030.8+0.1 in±0.0 in60.259.3 to 61.1Compare →
265/75R1530.6−0.1 in−0.4 in59.858.9 to 60.7Compare →
235/75R1730.9+0.1 in−1.6 in60.359.4 to 61.2Compare →
265/70R1630.6−0.1 in−0.4 in59.758.8 to 60.6Compare →

04 / Next

Compare it with your size

Tire size calculator275/45R21, or any two sizes: height, speedometer and gearing.Compare sizesTire sizes by vehicleEvery stock size on the trucks and SUVs we cover.Browse sizesFord Explorer tiresStock tires and wheels by trim, and what bigger tires change on the Ford Explorer.See the tiresVolkswagen Amarok tiresStock tires and wheels by trim, and what bigger tires change on the Volkswagen Amarok.See the tires

05 / FAQ

Questions people ask

What is 275/45R21 in inches?

About 30.7x10.8R21: 30.7 in tall and 10.8 in wide on a 21-inch wheel.

Which vehicles come with 275/45R21 tires?

In our data: Ford Explorer (2025) and Volkswagen Amarok (2023 and 2025).

How does 275/45R21 compare with the Ford Explorer’s other stock sizes?

275/45R21 is 0.3 in shorter: with a speedometer set for 255/65R18 it reads 1.0% high, 59.4 mph at an indicated 60. 275/45R21 is 0.3 in shorter: with a speedometer set for 255/55R20 it reads 1.0% high, 59.4 mph at an indicated 60.