Winch Terminology and Phrasing
Often Used with Winches
of You Winch
Winches can vary
greatly. Some are designed for light duty, occasional use
while others are designed for frequent, heavy use. When
choosing a winch, look at how your winch will be used. It's
better to spend a little more if you will use your winch
1.5 GVW Rule of Thumb
Recommended winch capacity over
vehicle weight. A rule of thumb is to
choose a winch with enough power for your vehicle. Typical use should
be calculated with this easy formula: gross vehicle weight x 1.5 =
minimum winch size.
Starting Input Torque
applied to the winch input shaft required to start a rated load upward
from a suspended position. It is expressed in pound-feet,
pound-inches, kilogram-meters or Newton-meters. May be referred to as
Running Input Torque
applied to the winch input shaft required to maintain upward movement
of rated load. It is expressed in pound-feet, pound-inches,
kilogram-meters or Newton-meters. May also be referred to as dynamic
Rated Input Speed
permissible input speed at rated load expressed in RPM. Exceeding
rated input speed may cause damage to the worm gear set.
Full Drum or Maximum Layers
drum containing the maximum number of cable layers which would leave a
freeboard of 0.7 x the cable diameter below the drum flange.
Drum Storage Capacity or
Cable Capacity on the Spool
length of a
specific diameter cable or
wire rope which may be wound on a cable drum without
exceeding the maximum number of layers. It is expressed in feet or
Rated Line Pull
This is the rated line pulling
capacity that a single line can handle safely without the use of a
snatch block or other device. This is measured on level ground
pulling dead weight (not rolling weight) from the first layer of
cable on the drum.
The line pull on
any layer that results from the output torque which produces maximum
rated line pull on the first layer. Rated first layer line pull is
based on maintaining an acceptable structural safety factor while
providing an acceptable component service life. Line pull is expressed
in pounds or kilograms.
Rated Line Speed
The line speed
on any specific layer that results from rated input speed. It is
expressed in feet/minute or meters/minute.
This the length of line that a
winch can spool off and on it's drum in one minute. Faster
line speeds provide quicker winch pulls and are generally found in
more expensive winches.
Thermal Rating (Duty Cycle)
result of a test, expressed as the distance (feet or meters) a load
travels up and down while hoisting and lowering a specified weight
until the lubricating oil rises from 100°F to 250°F (38°C to 121°C).
250°F (121°C) is the maximum intermittent gear oil temperature
allowed. Most gear oils "break down" rapidly at higher temperatures
and seals may be damaged.
Draw and the Battery
With the addition of a winch, the demand on your
electrical system can exceed the system's capabilities itself.
Consider upgrading your alternator to a high output alternator and be
sure your car battery is up to the demand of winching. For more
info on Battery Tech, See this.
Electric winches rely on the battery for power and
not the alternator. An automotive battery is designed to supply a
large draw of amps from the battery in a short period of time, such as
when you start your engine. Alternators typically supply under 100
amps. A winch during the pull may demand 400 or more amps
from your electric system. It is the job of the battery to supply
the the power. Therefore it is important that your battery is
capable of supplying the required power. Manufacturers of winches
typically recommend a Battery that can supply 650 CCA (Cold
Cranking Amps) minimum for
winching. Battery Leads to the winch should be at least 2 gauge
and shorter than 72" (1.83m).
Note: If you have an Optima battery or any
battery with side terminals (flush on the side and used with a small
bolt or connection), it's recommended that a winch is NOT connected to
these smaller terminals. In most cases they can not handle the full
amperage draw of a winch. Use of these small terminals can damage your
battery and potentially cause a fire.
Largest Recommended Wire Rope Size
Should be no larger than 1/8th the cable drum barrel diameter for
most recovery applications.
Also known as a
"dog-clutch" or "jaw clutch", consists of two or more drive lugs which
engage similar driven lugs to transmit torque to the cable drum.
The operation of
manually unspooling wire rope from the cable drum by pulling on the
free end of the rope while the cable drum is disconnected (declutched)
from its power train.
A single coil of wire rope
wound on a drum.
All wraps on the same level
between drum flanges.
The amount of drum
flange that extends past the last layer of wire rope.
A theoretical point
located midway between the first layer of wire rope on the cable drum
barrel and the top layer. Often used as a reference point in measuring
Gear Set Efficiency
relationship between the input horsepower transmitted to the winch by
the prime mover and the output horsepower transmitted by the winch to
the wire rope. Expressed as a percentage.
cable drum shaft is extended or replaced by an extra long shaft which
permits the use of capstans or CR reels at the side of the vehicle.
Usually installed on the curb side of the vehicle, most extension
shafts are limited to a standard length of 44 to 46-1/2 in. (112-118
cm) from the cable drum center-line.
Usually a small removable
drum used to apply force to fiber rope wrapped around the barrel with
tension applied by hand. Most have a nominal barrel diameter of 7 in.
reels are used for picking up and coiling power and telephone lines
which have been removed from the poles and lowered to the ground. Most
CR reels have a nominal barrel diameter of 20 in. (508 mm).
Bronze alloy gear
powered by the steel worm. Braden refers to the "bull gear" as the
That angle between
the wire rope's position at the extreme end wrap on a drum, and a line
drawn perpendicular to the axis of the drum through the center of the
nearest fixed sheave or load attachment point.