ALP 2011 Catalog General_wire_rope_information General Wire Rope Information

User Manual: general_wire_rope_information Grove Rough Terrain Crane

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1

SECTION 1 - Wire Rope

WIRE ROPE
General Information
Terminology & Properties
Terminology
With precise, moving parts, designed and manufactured to
bear definite relationship to
one another, Wire Rope can
be a complex mechanism.

the extreme outer dimensions of the strands. (See Fig.). New
wire rope is manufactured to an oversized diameter of
approximately 2-1/2%. This allows for the normal reduction
of diameter experienced when a new rope is placed under
load because of constructional stretch.
CAUTION: At NO time should the measured diameter
be less than the nominal diameter of the wire rope.
The grade of steel (or other material) utilized in the con-

Wire rope is generally composed of wires, strands and
the core (See Fig.). The
wires are helically laid
together in a precise geometric pattern to form the strand.
The strands helically laid
about the core to form the
wire rope. The process of
positioning the strands about
the core is called “closing”.
The process of positioning
the wires within the strand is
called “stranding”.
Wire rope varies:
• By Diameter
• The grade of steel utilized
• The direction of stranding and closing
• The finish on the wire (Bright, Galvanized, etc.)
• The core material
Each variation changes the performance characteristics of
the wire rope.
The first differentiation of wire rope is by diameter. The
diameter is measured at the diameter of the circle formed by

The RIGHT Way

The WRONG Way

struction of the wire rope has a major influence upon the
ultimate break strength. Generally most steel wire rope
today is at Improved Plow Steel Grade or IPS. In recent
years Extra Improved Plow Steel (EIPS) wire rope has
gained in popularity and is approximately 10% stronger than
IPS. Manufacturers have begun producing limited constructions of Extra Extra Improved Plow Steel (EEIPS), which is
10% higher than EIPS grade. Some special constructions
exceed EEIPS grade.
The “Lay” of the wire rope (the direction of stranding and
closing) directly affects the operating properties. In Regular
Lay wire rope, the direction of the wires are twisted in an
opposite direction than the direction of the strands. Regular
Lay may be Right Regular Lay or Left Regular Lay
depending upon the direction of the strands. (See Fig.).

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SECTION 1 - Wire Rope
In Lang Lay wire ropes the direction of the wires are
twisted in the same direction as the strands. Lang Lay may
be Right Lang Lay or Left Lang Lay depending upon the
direction of the strands. The wires of a regular wire rope
seem to travel parallel and along the length of the rope while
those of a lang lay rope appear to travel around the rope.

In addition, the Lay Length, the length of the rope necessary for one strand to travel completely around the rope (See
Fig.) may be varied slightly by manufacturer.
Most wire rope has a Bright, self-colored finish and a
coating of lubricant. However, many wire ropes are galvanized, stainless steel, or plastic/vinyl/urethane coated.
Most wire ropes are supplied with either a fiber or steel
core. The core’s primary function is to support the wire
strands of the rope, maintaining the corrective relative positions during the operating life. Fiber Cores are composed of
natural Vegetable Fiber Core (VFC - sisal, etc.) or Synthetic Fiber Core (PFC- polypropylene, etc.) which have
been formed into yarns and twisted into strands. Steel cores
may be Independent Wire
Rope Core (IWRC) or Wire
Strand Core (WSC). These
steel cores provide more support than fiber cores to the
outer strands during the rope’s
operating life. Steel cores
resist crushing, are more resistant to heat, reduce the amount
of stretch, and increase the
The Right Way
strength of the rope.

Unreeling & Uncoiling
The Right Way to Unreel. To unreel wire rope from a
heavy reel, place a shaft through the center and jack up the
reel far enough to clear the floor and revolve easily. One
person holds the end of the rope and walks a straight line
away from the reel, taking the wire rope off the top of the
reel. A second person regulates the speed of the turning reel
by holding a wood block against the flange as a brake, taking
care to keep slack from developing on the reel, as this can
easily cause a kink in the rope. Lightweight reels can be
properly unreeled using a vertical shaft; the same care
should be taken to keep the rope taut.
The Wrong Way to Unreel. If a reel of wire rope is laid
on its flange with it’s axis vertical to the floor and the rope

2

unreeled by throwing off the turns, spirals will occur and
kinks are likely to form in the rope. Wire rope always
should be handled in a way that neither twists nor unlays it.
If handled in a careless manner, reverse bends and kinks can
easily occur.
The Right Way
The Right Way to Uncoil.
There is only one way to uncoil
wire rope. One person must
hold the end of the rope while a
second person rolls the coil
along the floor, backing away.
The rope is allowed to uncoil
naturally with the lay, without
spiraling or twisting. Always
uncoil wire rope as shown.
The Wrong Way to Uncoil. If a coil of wire rope is laid flat
on the floor and uncoiled by pulling it straight off, spirals
will occur and kinking is likely. Torsions are put into the
rope by every loop that is pulled off, and the rope becomes
twisted and unmanageable. Also, wire rope cannot be
uncoiled like hemp rope. Pulling one end through the middle of the coil will only result in kinking.
Kinks
Great stress has been placed on the care that should be
taken to avoid kinks in wire rope. Kinks are places where
the rope has been unintentionally bent to a permanent set.
This happens where loops are pulled through by tension on
the rope until the diameter of the loop is only a few inches.
They are also caused by bending a rope around a sheave having too severe a radius. Wires in the strands at the kink are
permanently damaged and will not give normal service,
even after apparent “restraightening.”
Drum Winding. When wire rope is wound onto a sheave
or drum, it should bend in the manner in which it was originally wound. This will avoid causing a reverse bend in the
rope. Always wind wire rope from the top of the one reel
onto the top of the other. Also acceptable, but less so, is rereeling from the bottom of one reel to the bottom of another.
Re-reeling may also be done with reels having their shafts
vertical, but extreme care must be taken to ensure that the
rope always remains taut. It should never be allowed to drop
below the lower flange on the reel. A reel resting on the
floor with its axis horizontal may also be rolled along the
floor to unreel the rope.
Wire rope should be attached at the correct location on a
flat or smooth-faced drum, so that the rope will spool evenly,
with the turns lying snugly against each other in even layers.
If wire rope is wound on a smooth-face drum in the wrong
direction, the turns in the first layer of rope will tend to
spread apart on the drum. This results in the second layer of
rope wedging between the open coils, crushing and flattening the rope as successive layers are spooled.

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3

SECTION 1 - Wire Rope
been applied. Twist the two ends of the wire together, and
by alternately pulling and twisting, draw the seizing tight.
Method No. 2: Twist the two ends of the seizing wire
together, alternately twisting and pulling until the proper
tightness is achieved.
The Seizing Wire. The seizing wire should be soft or
annealed wire or strand. Seizing wire diameter and the
length of the seize will depend on the diameter of the wire
rope. The length of the seizing should never be less than the
diameter of the rope being seized.

A simple method of determining how a wire rope should be
started on a drum is shown in the above diagram. The
observer stands behind the drum, with the rope coming
towards him. Using the right hand for right-lay wire rope,
and the left hand for left lay wire rope, the clenched fist
denotes the drum, the extended index finger the oncoming
rope.

Proper end seizing while cutting and installing, particularly on rotation- resistant ropes, is critical. Failure to
adhere to simple precautionary measures may cause core
slippage and loose strands, resulting in serious rope damage.
Refer to the table for established guidelines. If core protrusion occurs beyond the outer strands, or core retraction
within the outer strands, cut the rope flush to allow for
proper seizing of both the core and outer strands.
In the absence of proper seizing wire or tools, the use of
sufficiently- sized hose clamps is acceptable.

Seizing Wire Rope
Proper seizing and cutting operations are not difficult to
perform, and they ensure that the wire rope will meet the
user’s performance expectations. Proper seizings must be
applied on both sides of the place where the cut is to be
made. In a wire rope, carelessly or inadequately seized ends
may become distorted and flattened, and the strands may
loosen. Subsequently, when the rope is operated, there may
be an uneven distribution of loads to the strands; a condition
that will significantly shorten the life of the rope.
Either of the following seizing methods is acceptable.
Method No. 1 is usually used on wire ropes over one inch in
diameter. Method No. 2 applies to ropes one inch and under.
Method No. 1

Method No. 2

Method No. 1: Place one end of the seizing wire in the
valley between two strands. Then turn its long end at right
angles to the rope and closely and tightly wind the wire back
over itself and the rope until the proper length of seizing has

Rope Design
All standard preformed wire rope
6x26 Reverse Lay
6-Pac, 6-Pac RV, Flex-X, Endurance Dyform® 6 & 8/8PI
All standard non-preformed wire rope
19x7 & 8x19 Class Rotation Resistant
SFP19, Endurance Dyform® 18/18PI, Endurance Constructex®,
Triple-PAC, Endurance 35x7®, Endurance 34LR/PI/MAX®
SFP 35

End Preparation
Single Seizing
Double Seizing
(Fused Ends
Recommended)
Double Seizing
AND Fused
Ends

Installation
The majority of wire rope problems occurring during operation actually begin during installation, when the rope is at
greatest risk of being damaged. Proper installation procedures are vital in the protection and performance of wire
rope products.
• Provide Proper Storage- Avoid damage and moisture
• Check the Rope Diameter Prior to Installation
• Use Proper Unreeling/Uncoiling Procedures
• Keep the Wraps Tight
• Treat Rotation-Resistant Ropes with Extra Care
• Secure the Ends Before Cutting
• Use a Wire Mesh Grip or Chinese Finger (to Prevent
Torque from the old rope transferring to the new rope)
• Always Perform a Break-In Procedure to Maximize Service Life
• Avoid Slack in the Rope
• Slowly Lift or Release the Load
• Use the Wire Rope ONLY for the Job it was Intended.

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11

SECTION 1 - Wire Rope

Wire Rope Definitions
Ropes
Spiral Rope: An assembly of two or more layers of shaped
and/or round wires laid helically over a center, usually a
single round wire. There are three categories of spiral rope,
i.e. spiral strand, half locked coil and full-locked coil.
Spiral Strand: An assembly of two or more layers of round
wires laid helically over a center, usually a single round
wire.
Half-locked coil Rope: A spiral rope type having an outer
layer of wires containing alternate half lock and round wires.
Full-locked Coil Rope: A spiral rope having an outer layer
of full lock wires.
Stranded Rope: An assembly of several strands laid helically in one or more layers around a core or center. There
are three categories of stranded rope, i.e. single layer,
multi-layer and parallel-closed.
Single Layer Rope: Stranded rope consisting of one layer of
strands laid helically over a core.
Note: Stranded ropes consisting of three of four outer strands
may, or may not, have a core. Some three and four strand single layer ropes are designed to generate torque levels equivalent to those generated by Rotation-Resistant ropes.

Rotation-Resistant rope: Stranded rope designed to generate
reduced levels of torque and rotation when loaded and
comprising an assembly of two or more layers of strands laid
helically around the center, the direction of lay of the outers
strands being opposite to that of the underlying layer.
Rotation-Resistant rope: category 1:
Stranded rope constructed in such a manner that it
displays little or no tendency to rotate, or, if guided, transmits
little or no torque, has at least fifteen outer strands and comprising an assembly of at least three layers of strands laid
helically over a center in two or three operations, the direction of lay of the outer strands being opposite to that of the
underlying layer.
Rotation-Resistant rope: category 2:
Stranded rope constructed in such a manner that it has significant resistance to rotation, has at least ten out strands and
comprising an assembly of two or more layers of strands
laid helically over a centre in two or three operations, the
direction of lay of the outer strands being opposite to that of
the underlying layer.
Rotation-Resistant rope: category 3:
Stranded rope constructed in such a manner that it has limited resistance to rotation, has no more than nine outer
strands and comprising an assembly of two layers of strands
laid helically over a center in two operations, the direction of
lay of the outer strands being opposite to that of the underlying layer.
Compacted Strand Rope: Rope in which the outer strands,
prior to closing of the rope, are subjected to a compacting
process such as drawing, rolling or swaging.
Compacted Swaged Rope: Rope which is subjected to a
compacting process after closing, thus reducing its diameter.

Plastic (Solid Polymer) Filled Rope: Rope in which the free
internal spaces are filled with a solid polymer. The polymer
extends to, or slightly beyond, the outer circumference of the
rope.
Cushioned Rope: Stranded rope in which the inner layers,
inner strands or core strands are covered with solid polymers
or fibers to form a cushion between adjacent strands or
layers of strands.
Cushion Core Rope: Stranded rope in which the core is
covered (coated) or filled and covered (coated) with a solid
polymer.
Solid Polymer Covered Rope: Rope which is covered
(coated) with a solid polymer.
Solid Polymer Covered and Filled Rope: Rope which is
covered (coated) and filled with a solid polymer.
Rope Grade (Rr): A number corresponding to a wire tensile
strength grade on which the minimum breaking force of a
rope is calculated.
Note: It does not imply that the actual tensile strength grades of
the wires in a rope are necessarily the same as the rope grade.

Preformed Rope: Stranded rope in which the wires in the
strands and the strands in the rope have their internal stresses
reduced resulting in a rope in which, after removal of any
serving, the wires and the strands will not spring out of the
rope formation.
Note: Rotation Resistant stranded ropes should be regarded as
non-performed rope even though the strands may have been
partially (lightly) preformed during the closing process.

Rope Class: A grouping of rope constructions where the
number of outer strands and the number of wires and how
they are laid up are within defined limits, resulting in ropes
within the class having similar strength and rotational
properties.
Rope Construction: System which denotes the arrangement
of the strands and wires within a rope, e.g. 6x19S; 6x36WS;
18x7; 34x7.
Cable-laid Rope: An assembly of several (usually six) single
layer stranded ropes (referred to as unit ropes) laid helically
over a core (usually a seventh single layer stranded rope).
Braided Rope: An assembly of several round strands braided
in pairs.
Electro-mechanical Rope: A stranded or spiral containing
electrical conductors.

Strand and Rope Lays
Lay direction of strand: The direction right (z) or left (s)
corresponding to the direction of lay of the outer layer of
wires in relation to the longitudinal axis of the strand.
Lay direction of rope: The direction right (Z) or left (S)
corresponding to the direction of lay of the outer strands in
relation to the longitudinal axis of a stranded rope or the
direction of lay of the outer wires in relation to the
longitudinal axis of a spiral rope.
Regular Lay: Stranded rope in which the direction of lay of
the wires in the outer strands is in the opposite direction to

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SECTION 1 - Wire Rope
the lay of the outer strands in the rope. Right Regular Lay is
designated zZ and Left Regular Lay is designated zS.
Note: This type of lay is sometimes referred to as 'ordinary' lay.

Lang Lay: Stranded rope in which the direction of lay of the
wires in the outer strands is the same as that of the outer
strands in the rope. Right Lang Lay is designated zZ and
Left Lang lay is designated sS.
Alternate Lay: Stranded rope in which the lay of the outer
strands is alternatively Lang's lay and regular lay. Right
hand alternate lay is designated AZ and left hand alternate
lay is designated AS.
Contra-Lay: Rope in which at least one layer of wires in a
spiral rope or one layer of strands in a stranded rope is laid in
the opposite direction to the other layer(s) of wire or strands
respectively.
Note: Contra-lay is only possible in spiral ropes having
more than one layer of wires in, multi-layer stranded ropes.
Rope Lay Length (Stranded Rope): That distance parallel to
the axis of the rope in which the outer strands make one
complete turn (or helix) about the axis of the rope.

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to the amount of rotation when one end of the rope is free to
rotate and the rope is subjected to tensile loading.
Initial extension: Amount of extension which is attributed to
the initial bedding down of the wires within the strands and
the strands within the rope due to tensile loading.
Note: This is sometimes referred to as constructional stretch.
Elastic extension: Amount of extension which follows
Hooke's Law within certain limits due to application of a
tensile load.
Permanent rope extension: Non-elastic extension.

Cores
Core: Central element, usually of fiber or steel, of a single
layer stranded rope, around which are laid helically the outer
strands of a stranded rope or the outer unit ropes of a
cable-laid rope.
Fiber core: Core made from either natural (e.g. hemp, sisal)
or synthetic fibers (e.g. polypropylene) and designated by its
diameter and runnage.
Steel Core: Core produced either as an independent wire
rope (e.g. 7x7) or wire strand (e.g. 1x7).
Solid polymer core: Core produced as a single element of
solid polymer having a round or grooved shaped. It may
also contain internal elements of wire or fiber.
Insert: Element of fiber or solid polymer so positioned as to
separate adjacent strands or wires in the same or overlying
layers and fill, or partly fill, some of the interstices in the
rope.

Rope Characteristics and Properties
Fill factor: The ratio between the sum of the nominal
cross-sectional areas of all the load bearing wires in the rope
and the circumscribed area of the rope based on its nominal
diameter.
Spinning loss factor: The ratio between the calculated
minimum breaking force of the rope and the calculated
minimum aggregate breaking force of the rope.
Minimum breaking force (T min): Specified value, in tons
or kN, below which the measured breaking force is not
allowed to fall in a prescribed test.
Rope torque: Value, usually expressed in ft pounds or N.m,
resulting from either test or calculation, relating to the torque
generated when both ends of the rope are fixed and the rope
is subjected to tensile loading.
Rope turn: Value, usually expressed in degrees per
foot/meter, resulting from either test or calculation, relating
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