40×14.50R20 in inches

A 40×14.50R20 tire is 40.0″ tall and 14.5″ wide, and fits a 20″ wheel.

Diameter40.00″

Width14.50″

Sidewall10.00″

Drawn to scale. Nominal dimensions calculated from the size code.

Manufacturer data

How tall 40×14.50R20 tires really are

Heights published by Mickey Thompson for the one tire in this size.

The one tire listed, the Mickey Thompson Baja Legend MTZ, measures 39.80″: 0.20″ shorter than the size code's 40.00″.

1 tire in 40×14.50R20

Sort by the spec you care about.

	Load					Revs/mi	Source
Mickey Thompson Baja Legend MTZMud-terrain	LT D · 128Q	39.80	94.0	22.0	3,970	–	Spec page

Is a 40×14.50R20 really 40 inches tall?

39.8″

Shorter. The name says 40″, and the 1 tire here publishes 39.80″.

All 40-inch tire sizes, on every wheel size.

Compare with nearby sizes

Differences in overall diameter, calculated from each size code.

Size	Diameter ″	vs 40×14.50R20	Difference
38×13.50R20	38.00	-2.00″	-5.0%
38×15.50R20	38.00	-2.00″	-5.0%
40×13.50R20	40.00	0.00″	0.0%
40×15.50R20	40.00	0.00″	0.0%
42×13.50R20	42.00	+2.00″	+5.0%

How to read 40×14.50R20

How to read any tire size

How 40X14.50R20LT 128Q 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.

140Overall diameter

40 inches tall, measured on the approved wheel. Flotation sizes give every number in inches.

214.50Section width

14.50 inches across the widest point, or 368 mm.

3RConstruction

Radial construction.

420Wheel diameter

Mounts on a 20-inch wheel. Approved wheel widths run 10.0″ to 13.0″.

5LTLight truck

Marks a light truck (LT) tire.

6128Load index

Each tire carries up to 3,970 lb (1,800 kg) at its maximum pressure.

7QSpeed rating

Rated for up to 99 mph sustained.

DLoad range

Printed separately as "LOAD RANGE D": a 8-ply rating, inflated up to 65 psi (standard load-range table). The load range D tires here carry up to 3,970 lb each, as published.

Specification	Inches	Metric
Overall diameter	40.00	1016 mm
Section width	14.50	368 mm
Sidewall height	10.00	254.0 mm
Circumference	125.7	3,192 mm
Revolutions per mile (calculated, unloaded)	504.2	313 per km
Approved wheel width	10.0–13.0	254–330 mm

Speedometer error after switching to 40×14.50R20

Your actual speed– mph

Questions about 40×14.50R20

What is 40×14.50R20 in inches?

40.00 inches tall, 14.50 inches wide, on a 20-inch wheel. Manufacturers publish 39.80 inches for the 1 tires listed here.

What wheel width do I need for 40×14.50R20?

Manufacturers approve 10.0–13.0″ wide wheels for this size.

How much taller is 40×14.50R20 than 38×15.50R20?

2.00 inches taller on paper (40.00″ vs 38.00″), which raises the axle about 1.00″. Your speedometer will read about 5.3% slow.