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325/40R22 in inches

A 325/40R22 tire is 32.2″ tall and 12.8″ wide, and fits a 22″ wheel. In inches it is written 32.2×12.8R22.

Diameter32.24″
Width12.80″
Sidewall5.12″
325/40R22 drawn to scale: 32.24 inch diameter, 5.12 inch sidewall, 22 inch wheel, 12.80 inch tread width22″ wheel5.12″32.24″ overall12.80″ wideSide view
Drawn to scale. Nominal dimensions calculated from the size code.
Manufacturer data

How tall 325/40R22 tires really are

Heights published by Michelin for the one tire in this size. Their published revolutions per mile work out to 31.3″ under load (below).

The one tire listed, the Michelin Pilot Sport 4 SUV, measures 32.20″: 0.04″ shorter than the size code's 32.24″.

Height under load31.3″

Published revs per mile (645) mean the tire rolls like a 31.3″ tire on the vehicle. Use this for speedometer calibration.

1 tire in 325/40R22

Sort by the spec you care about.

LoadRevs/miSource
Michelin Pilot Sport 4 SUVPerformanceSL · 114Y32.2037.39.52,601645Spec page

Is 325/40R22 a 32-inch tire?

≈32″

Yes. The size code works out to 32.24″, and the 1 tire here publishes 32.20″, so people call it a 32.

All 32-inch tire sizes, on every wheel size.

Compare with nearby sizes

Differences in overall diameter, calculated from each size code.

SizeDiameter ″vs 325/40R22Difference
295/40R2231.29-0.94″-2.9%
305/40R2231.61-0.63″-2.0%
275/45R2231.74-0.49″-1.5%
285/45R2232.10-0.14″-0.4%
265/50R2232.43+0.20″+0.6%
305/45R2232.81+0.57″+1.8%
275/50R2232.83+0.59″+1.8%
33×12.50R2233.00+0.76″+2.4%
355/40R2233.18+0.94″+2.9%
285/50R2233.22+0.98″+3.1%

How to read 325/40R22

How to read any tire size

325/40R22 114Y as printed on the tire sidewall, with each part numbered325/40R22 114Y123456
How 325/40R22 114Y is printed on the sidewall. It's the most common code among the 1 tire here; tires in this size come in other load and speed ratings too.
1325Section width

325 mm across the widest point, or 12.80 inches. Every 325 size

240Aspect ratio

A percentage, not a measurement: the sidewall is 40% as tall as the tire is wide, which is 130.0 mm or 5.12 inches.

3RConstruction

Radial construction.

422Wheel diameter

Mounts on a 22-inch wheel. Approved wheel widths run 11.0″ to 13.0″.

5114Load index

Each tire carries up to 2,601 lb (1,180 kg) at its maximum pressure.

6YSpeed rating

Rated for up to 186 mph sustained.

SpecificationInchesMetric
Overall diameter32.24819 mm
Section width12.80325 mm
Sidewall height5.12130.0 mm
Circumference101.32,572 mm
Revolutions per mile (calculated, unloaded)625.6389 per km
Revolutions per mile (published by manufacturers)645401 per km
Approved wheel width11.0–13.0279–330 mm

Speedometer error after switching to 325/40R22

Your actual speed– mph

Questions about 325/40R22

What is 325/40R22 in inches?

32.24 inches tall, 12.80 inches wide, on a 22-inch wheel. Written in inches, that is roughly 32.2×12.8R22.

What wheel width do I need for 325/40R22?

Manufacturers approve 11.0–13.0″ wide wheels for this size.

How many revolutions per mile does a 325/40R22 make?

Published figures run 645 revolutions per mile. The calculated figure is 625.6, but manufacturers measure the tire under load, where it rolls on a smaller radius.

How much taller is 325/40R22 than 285/45R22?

0.14 inches taller on paper (32.24″ vs 32.10″), which raises the axle about 0.07″. Your speedometer will read about 0.4% slow.