255/55R19 tire size

A 255/55R19 tire is 30.0 inches (763 mm) tall and 10.0 inches (255 mm) wide, for a 19-inch wheel. Each sidewall is 5.5 inches (140 mm), 55% of the width, and the tire makes about 671 revolutions a mile.

Sources checked

Dimension255/55R19
Overall diameter30.04 in (763 mm)
Section width10.04 in (255 mm)
Sidewall height5.52 in (140 mm)
Aspect ratio55%
Rim diameter19 in
Circumference94.4 in (2,397 mm)
Revolutions per mile671
Revolutions per km417

Compare 255/55R19 with another size

Metric, LT and flotation

As printed on the sidewall: 265/70R17, LT285/75R16, 33x12.50R15.

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A 255/55R19 tire is

30.0in tall763mm

on a 19-inch wheel

Width
10.04 in (255 mm)
Sidewall
5.52 in (140 mm)
Circumference
94.4 in
Revolutions per mile
671

255/55R19 in full

Dimension255/55R19
Overall diameter30.04 in (763 mm)
Section width10.04 in (255 mm)
Sidewall height5.52 in (140 mm)
Aspect ratio55%
Rim diameter19 in
Circumference94.4 in
Revolutions per mile671
Revolutions per km417

The working

  1. 255/55R19: sidewall = 255 mm × 55% = 140.3 mm = 5.52 in.
  2. Diameter = rim + 2 × sidewall = 19 + 2 × 5.52 = 30.04 in (763 mm).
  3. Circumference = π × 30.04 = 94.4 in; revolutions per mile = 63,360 ÷ 94.4 = 671.

Where the 255/55R19 numbers come from

The section width is 255 mm (10.04 inches), and each sidewall is 55% of it: 140.3 mm, or 5.52 inches. Two sidewalls and the 19-inch rim make 30.04 inches (763 mm).

One turn covers π × 30.04 = 94.4 inches, so the tire turns 671 times a mile and 417 times a kilometer.

What tire makers publish for 255/55R19

Inflated on the maker’s measuring rim. The percentage is the printed diameter against the 30.04 inches worked out above.

TireSize as printedDiameterWidthRevs per mile
Toyo Open Country A/T III255/55R1930 in (−0.1%)10.4 in692

Other 19-inch sizes against 255/55R19

Each size’s height against 255/55R19, and what a speedometer set for 255/55R19 shows at 60 mph with that size on.

SizeDiameterWidthHeight changeAt 60 mph shown
235/40R1926.4 in9.3 in−12.1%52.7 mph
235/55R1929.2 in9.3 in−2.9%58.3 mph
245/40R1926.7 in9.6 in−11.1%53.4 mph
245/45R1927.7 in9.6 in−7.9%55.3 mph

Every size: the tire size calculator. With the wheels off, the nuts go back on at your vehicle’s lug nut torque.

Questions

What is 255/55R19 in inches?

About 30.0x10.0R19: 30.0 inches tall and 10.0 inches wide on a 19-inch wheel, with 5.5-inch sidewalls. Exactly, 19 + 2 × 255 mm × 0.55 ÷ 25.4 = 30.04 inches.

How many revolutions per mile does a 255/55R19 make?

671 by its diameter: 63,360 inches in a mile ÷ 94.4 inches a turn. Tire makers’ published figures are measured under load, when the tire rolls on a slightly smaller radius, and run 2.8% to 3.3% higher in Toyo’s tables.

Is LT255/55R19 the same size as P255/55R19?

In dimensions, yes: the numbers mean the same in every metric size. The letters mark what the tire is built for, and an LT tire’s load is rated differently, so check the load index and pressure your vehicle needs before swapping one for the other.

Sources

  1. Bridgestone Americas: Determining tire size: P-metric, Euro-metric, LT-metric, C-type and flotation sizes, and what each number means (checked October 28, 2026)
  2. Toyo Tires: Extensa A/S II sizes and specifications: inflated overall diameter and width, revolutions per mile (checked October 28, 2026)
  3. Toyo Tires: Proxes Sport A/S sizes and specifications: inflated overall diameter and width, revolutions per mile (checked October 28, 2026)
  4. Toyo Tires: Open Country A/T III sizes and specifications: P-metric, LT-metric and flotation sizes, with revolutions per mile (checked October 28, 2026)
  5. Nitto Tire: Trail Grappler M/T sizes and specs: inflated overall diameter and width, LT-metric and flotation sizes (checked October 28, 2026)

Spotted a number that doesn’t match your manual or a source? Tell us; corrections are logged on the sources page.