tireheight.com

245/40R20 in inches

A 245/40R20 tire is 27.7″ tall and 9.6″ wide, and fits a 20″ wheel. In inches it is written 27.7×9.6R20.

Diameter27.72″
Width9.65″
Sidewall3.86″
245/40R20 drawn to scale: 27.72 inch diameter, 3.86 inch sidewall, 20 inch wheel, 9.65 inch tread width20″ wheel3.86″27.72″ overall9.65″ wideSide view
Drawn to scale. Nominal dimensions calculated from the size code.
Manufacturer data

How tall 245/40R20 tires really are

Heights published by BFGoodrich, General, Michelin and Toyo for all 20 tires in this size. Their published revolutions per mile work out to 26.9″ under load (below).

Real 245/40R20 tires measure 27.70–27.72″, against 27.72″ from the size code. They run both taller and shorter than the size code.

Height under load26.9″

Published revs per mile (749–750) mean the tire rolls like a 26.9″ tire on the vehicle. Use this for speedometer calibration.

Weight spread24.7–31.5 lb

The lightest (Toyo Extensa HP II, XL) is 6.8 lb lighter per corner than the heaviest (Toyo Observe G3-Ice, XL).

20 tires in 245/40R20

Sort by the spec you care about.

LoadRevs/miSource
Toyo Extensa HP IIPerformanceXL · 99W27.7224.79.61,709750Spec page
General AltiMAX RT45TouringXL · 99V27.7025.111.01,709750Spec page
Michelin Pilot Sport 4 SPerformanceXL · 99(Y)27.7025.39.01,709750Spec page
Michelin Pilot Sport All-Season 4PerformanceXL · 99Y27.7025.910.01,709750Spec page
Michelin Primacy Tour A/STouringXL · 99V27.7026.29.01,709750Spec page
Michelin Pilot Super SportPerformanceXL · 99(Y)27.7026.59.01,709750Spec page
Toyo Proxes Sport 2PerformanceXL · 99(Y)27.7026.59.21,709750Spec page
General G-MAX RSPerformanceXL · 99Y27.7026.610.01,709750Spec page
Michelin Pilot Sport 4 SPerformanceXL · 99(Y)27.7026.69.51,709750Spec page
Toyo Proxes SportPerformanceXL · 99Y27.7226.99.61,709750Spec page
General G-MAX AS07PerformanceXL · 99W27.7027.010.01,709750Spec page
Michelin Pilot Sport EVPerformanceXL · 99Y27.7027.68.01,709750Spec page
Michelin CrossClimate2All-seasonXL · 99W27.7227.910.01,709750Spec page
BFGoodrich g-Force Phenom T/APerformanceXL · 99Y27.7228.28.01,709750Spec page
Michelin X-Ice SnowWinterXL · 99H27.7228.410.51,709750Spec page
Toyo CelsiusAll-weatherXL · 99V27.7228.410.61,709750Spec page
Toyo Celsius SportPerformanceXL · 99Y27.7229.29.41,709750Spec page
BFGoodrich g-Force COMP-2 A/S PLUSPerformanceXL · 99W27.7229.99.01,709750Spec page
Toyo Proxes Sport A/SPerformanceXL · 99Y27.7230.69.41,709750Spec page
Toyo Observe G3-IceWinterXL · 99T27.7231.512.01,709749Spec page

Is 245/40R20 a 28-inch tire?

≈28″

Yes. The size code works out to 27.72″, and the 20 tires here publish 27.70–27.72″, so people call it a 28.

All 28-inch tire sizes, on every wheel size.

Compare with nearby sizes

Differences in overall diameter, calculated from each size code.

SizeDiameter ″vs 245/40R20Difference
265/35R2027.30-0.41″-1.5%
235/40R2027.40-0.31″-1.1%
315/30R2027.44-0.28″-1.0%
275/35R2027.58-0.14″-0.5%
215/45R2027.62-0.10″-0.4%
325/30R2027.68-0.04″-0.1%
285/35R2027.85+0.14″+0.5%
335/30R2027.91+0.20″+0.7%
255/40R2028.03+0.31″+1.1%
295/35R2028.13+0.41″+1.5%

How to read 245/40R20

How to read any tire size

245/40R20 99Y as printed on the tire sidewall, with each part numbered245/40R20 99Y123456
How 245/40R20 99Y is printed on the sidewall. It's the most common code among the 20 tires here (7 of them); tires in this size come in other load and speed ratings too.
1245Section width

245 mm across the widest point, or 9.65 inches. Every 245 size

240Aspect ratio

A percentage, not a measurement: the sidewall is 40% as tall as the tire is wide, which is 98.0 mm or 3.86 inches.

3RConstruction

Radial construction.

420Wheel diameter

Mounts on a 20-inch wheel. Approved wheel widths run 8.0″ to 9.5″.

599Load index

Each tire carries up to 1,709 lb (775 kg) at its maximum pressure.

6YSpeed rating

Rated for up to 186 mph sustained.

XLExtra load

Printed after the size.

SpecificationInchesMetric
Overall diameter27.72704 mm
Section width9.65245 mm
Sidewall height3.8698.0 mm
Circumference87.12,212 mm
Revolutions per mile (calculated, unloaded)727.7452 per km
Revolutions per mile (published by manufacturers)749–750465–466 per km
Approved wheel width8.0–9.5203–241 mm

Speedometer error after switching to 245/40R20

Your actual speed– mph

Questions about 245/40R20

What is 245/40R20 in inches?

27.72 inches tall, 9.65 inches wide, on a 20-inch wheel. Written in inches, that is roughly 27.7×9.6R20.

How much does a 245/40R20 tire weigh?

Between 24.7 lb and 31.5 lb for the 20 tires listed here. The lightest is the Toyo Extensa HP II (XL); the heaviest is the Toyo Observe G3-Ice (XL).

What wheel width do I need for 245/40R20?

Manufacturers approve 8.0–9.5″ wide wheels for this size.

How many revolutions per mile does a 245/40R20 make?

Published figures run 749–750 revolutions per mile. The calculated figure is 727.7, but manufacturers measure the tire under load, where it rolls on a smaller radius.

How much taller is 245/40R20 than 325/30R20?

0.04 inches taller on paper (27.72″ vs 27.68″), which raises the axle about 0.02″. Your speedometer will read about 0.1% slow.