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255/30R19 in inches

A 255/30R19 tire is 25.0″ tall and 10.0″ wide, and fits a 19″ wheel. In inches it is written 25.0×10.0R19.

Diameter25.02″
Width10.04″
Sidewall3.01″
255/30R19 drawn to scale: 25.02 inch diameter, 3.01 inch sidewall, 19 inch wheel, 10.04 inch tread width19″ wheel3.01″25.02″ overall10.04″ wideSide view
Drawn to scale. Nominal dimensions calculated from the size code.
Manufacturer data

How tall 255/30R19 tires really are

Heights published by Michelin and Toyo for all 5 tires in this size. Their published revolutions per mile work out to 24.3–24.4″ under load (below).

Real 255/30R19 tires measure 25.08–25.10″, against 25.02″ from the size code. Every one runs taller than the size code.

Height under load24.3–24.4″

Published revs per mile (828–829) mean the tire rolls like a 24.3–24.4″ tire on the vehicle. Use this for speedometer calibration.

Weight spread22.6–26.0 lb

The lightest (Toyo Proxes Sport 2, XL) is 3.4 lb lighter per corner than the heaviest (Michelin Pilot Sport 4 S, XL).

5 tires in 255/30R19

Sort by the spec you care about.

LoadRevs/miSource
Toyo Proxes Sport 2PerformanceXL · 91(Y)25.1022.69.11,356828Spec page
Toyo Proxes Sport A/SPerformanceXL · 91Y25.0823.99.31,356828Spec page
Michelin Pilot Sport 4 SPerformanceXL · 91(Y)25.1024.09.51,356829Spec page
Michelin Pilot Sport All-Season 4PerformanceXL · 91Y25.1024.310.01,356829Spec page
Michelin Pilot Sport 4 SPerformanceXL · 91Y25.1026.09.51,356829Spec page

Is 255/30R19 a 25-inch tire?

≈25″

Yes. The size code works out to 25.02″, and the 5 tires here publish 25.08–25.10″, so people call it a 25.

Compare with nearby sizes

Differences in overall diameter, calculated from each size code.

SizeDiameter ″vs 255/30R19Difference
245/30R1924.79-0.24″-0.9%
295/30R1824.97-0.06″-0.2%
255/35R1825.03+0.00″+0.0%
225/40R1825.09+0.06″+0.3%
225/35R1925.20+0.18″+0.7%
265/30R1925.26+0.24″+0.9%
235/35R1925.48+0.45″+1.8%
275/30R1925.50+0.47″+1.9%
285/30R1925.73+0.71″+2.8%
245/35R1925.75+0.73″+2.9%

How to read 255/30R19

How to read any tire size

255/30R19 91Y as printed on the tire sidewall, with each part numbered255/30R19 91Y123456
How 255/30R19 91Y is printed on the sidewall. It's the most common code among the 5 tires here (3 of them); tires in this size come in other load and speed ratings too.
1255Section width

255 mm across the widest point, or 10.04 inches. Every 255 size

230Aspect ratio

A percentage, not a measurement: the sidewall is 30% as tall as the tire is wide, which is 76.5 mm or 3.01 inches.

3RConstruction

Radial construction.

419Wheel diameter

Mounts on a 19-inch wheel. Approved wheel widths run 8.5″ to 9.5″.

591Load index

Each tire carries up to 1,356 lb (615 kg) at its maximum pressure.

6YSpeed rating

Rated for up to 186 mph sustained.

XLExtra load

Printed after the size.

SpecificationInchesMetric
Overall diameter25.02636 mm
Section width10.04255 mm
Sidewall height3.0176.5 mm
Circumference78.61,997 mm
Revolutions per mile (calculated, unloaded)806.0501 per km
Revolutions per mile (published by manufacturers)828–829514–515 per km
Approved wheel width8.5–9.5216–241 mm

Speedometer error after switching to 255/30R19

Your actual speed– mph

Questions about 255/30R19

What is 255/30R19 in inches?

25.02 inches tall, 10.04 inches wide, on a 19-inch wheel. Written in inches, that is roughly 25.0×10.0R19.

How much does a 255/30R19 tire weigh?

Between 22.6 lb and 26.0 lb for the 5 tires listed here. The lightest is the Toyo Proxes Sport 2 (XL); the heaviest is the Michelin Pilot Sport 4 S (XL).

What wheel width do I need for 255/30R19?

Manufacturers approve 8.5–9.5″ wide wheels for this size.

How many revolutions per mile does a 255/30R19 make?

Published figures run 828–829 revolutions per mile. The calculated figure is 806.0, but manufacturers measure the tire under load, where it rolls on a smaller radius.

How much taller is 255/30R19 than 245/30R19?

0.24 inches taller on paper (25.02″ vs 24.79″), which raises the axle about 0.12″. Your speedometer will read about 1.0% slow.