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305/40R22 in inches

A 305/40R22 tire is 31.6″ tall and 12.0″ wide, and fits a 22″ wheel. In inches it is written 31.6×12.0R22.

Diameter31.61″
Width12.01″
Sidewall4.80″
305/40R22 drawn to scale: 31.61 inch diameter, 4.80 inch sidewall, 22 inch wheel, 12.01 inch tread width22″ wheel4.80″31.61″ overall12.01″ wideSide view
Drawn to scale. Nominal dimensions calculated from the size code.
Manufacturer data

How tall 305/40R22 tires really are

Heights published by General, Michelin and Toyo for all 4 tires in this size. Their published revolutions per mile work out to 30.7″ under load (below).

Real 305/40R22 tires measure 31.60–31.61″, against 31.61″ from the size code. They run both taller and shorter than the size code.

Height under load30.7″

Published revs per mile (657–658) mean the tire rolls like a 30.7″ tire on the vehicle. Use this for speedometer calibration.

Weight spread38.0–43.7 lb

The lightest (General G-MAX AS07, XL) is 5.7 lb lighter per corner than the heaviest (Toyo Proxes ST III, XL).

4 tires in 305/40R22

Sort by the spec you care about.

LoadRevs/miSource
General G-MAX AS07PerformanceXL · 114V31.6038.011.02,601657Spec page
Michelin Defender LTX M/S 2All-seasonXL · 114H31.6039.911.02,601658Spec page
Michelin Pilot Sport All-Season 4PerformanceXL · 114Y31.6040.69.52,601658Spec page
Toyo Proxes ST IIIPerformanceXL · 114V31.6143.710.12,601657Spec page

Is 305/40R22 a 32-inch tire?

≈32″

Close. The size code works out to 31.61″, and the 4 tires here publish 31.60–31.61″, 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 305/40R22Difference
275/40R2230.66-0.94″-3.0%
315/35R2230.68-0.93″-2.9%
325/35R2230.96-0.65″-2.1%
285/40R2230.98-0.63″-2.0%
255/45R2231.04-0.57″-1.8%
295/40R2231.29-0.31″-1.0%
275/45R2231.74+0.14″+0.4%
285/45R2232.10+0.49″+1.6%
325/40R2232.24+0.63″+2.0%
265/50R2232.43+0.83″+2.6%

How to read 305/40R22

How to read any tire size

305/40R22 114V as printed on the tire sidewall, with each part numbered305/40R22 114V123456
How 305/40R22 114V is printed on the sidewall. It's the most common code among the 4 tires here (2 of them); tires in this size come in other load and speed ratings too.
1305Section width

305 mm across the widest point, or 12.01 inches. Every 305 size

240Aspect ratio

A percentage, not a measurement: the sidewall is 40% as tall as the tire is wide, which is 122.0 mm or 4.80 inches.

3RConstruction

Radial construction.

422Wheel diameter

Mounts on a 22-inch wheel. Approved wheel widths run 10.0″ to 12.0″.

5114Load index

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

6VSpeed rating

Rated for up to 149 mph sustained.

XLExtra load

Printed after the size.

SpecificationInchesMetric
Overall diameter31.61803 mm
Section width12.01305 mm
Sidewall height4.80122.0 mm
Circumference99.32,522 mm
Revolutions per mile (calculated, unloaded)638.1396 per km
Revolutions per mile (published by manufacturers)657–658408–409 per km
Approved wheel width10.0–12.0254–305 mm

Speedometer error after switching to 305/40R22

Your actual speed– mph

Questions about 305/40R22

What is 305/40R22 in inches?

31.61 inches tall, 12.01 inches wide, on a 22-inch wheel. Written in inches, that is roughly 31.6×12.0R22.

How much does a 305/40R22 tire weigh?

Between 38.0 lb and 43.7 lb for the 4 tires listed here. The lightest is the General G-MAX AS07 (XL); the heaviest is the Toyo Proxes ST III (XL).

What wheel width do I need for 305/40R22?

Manufacturers approve 10.0–12.0″ wide wheels for this size.

How many revolutions per mile does a 305/40R22 make?

Published figures run 657–658 revolutions per mile. The calculated figure is 638.1, but manufacturers measure the tire under load, where it rolls on a smaller radius.

How much taller is 305/40R22 than 295/40R22?

0.31 inches taller on paper (31.61″ vs 31.29″), which raises the axle about 0.16″. Your speedometer will read about 1.0% slow.