How tall is a 285/45R21 tire?

A 285/45R21 has a nominal overall diameter of 31.1 inches (790 mm), calculated as the 21-inch wheel plus two sidewalls. This is the unloaded figure — a fitted tire sits fractionally shorter under the weight of the vehicle.

What wheel size does a 285/45R21 tire fit?

A 285/45R21 fits a wheel of 21 inches in diameter. The wheel also has to be within the rim width range the manufacturer publishes for this size, which is printed in the tire's spec sheet.

What do the numbers in 285/45R21 mean?

285 is the section width in millimetres. 45 is the aspect ratio — the sidewall is 45% of the width, so 128.3 mm here. R marks the construction (radial). 21 is the wheel diameter in inches.

Size Dimensions & Specs

Tires Size 285/45R21

Dimensions, specs, and every size 285/45R21 tire currently in stock

Overall Height

31.1"

790 mm · calculated

Section Width

285 mm

11.22 inches

Sidewall Height

5.05"

128.3 mm · 45% profile

Wheel Diameter

21"

533.4 mm

285/45R21 Specifications

Read directly from the size code. Load index, speed rating, and rim width range vary by model.

Specification	Imperial	Metric
Section width	11.22 in	285 mm
Aspect ratio	45%	—
Sidewall height	5.05 in	128.3 mm
Overall diameter (calculated)	31.1 in	790 mm
Wheel / rim diameter	21 in	533.4 mm
Construction	Radial	—

What does 285/45R21 mean?

Reading the code on your sidewall

Section width

285 mm

The distance from sidewall to sidewall across the tire's widest point.

Aspect ratio

45% profile

The sidewall stands 45% of the section width, which is 128.3 mm on this size.

Construction (R)

Radial

The body plies run across the tire at right angles to the direction of travel.

Wheel diameter

21 in

Fits a wheel measuring 21 inches across.

285/45R21 Questions & Answers

Dimensions and fitment guidelines for size 285/45R21

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