Caster Rigs

January 18, 2022

A caster is composed of 4 major components, the wheel, axle, nut & rig. The rig
is the part of the caster that cradles the wheel & allows it it to be attached
to an object. The rig plays a major role in a caster as it dictates the mounting
method, type of caster (swivel or rigid), capacity & longevity. When it comes
down to finding the right caster for you, consider the type of rig you are
getting. 

Types of Rigs

Mounting Methods

Plate

Plates vary in many different sizes &
shapes. Plates are more secure than
stems as a mounting method because
plates typically utilize 4 areas (bolts) to
secure them to an object as opposed to
1 area. We recommend using a plate
caster when possible if you have the
amount of space.

Stem

Stems vary in many different sizes & kinds
(threaded, grip ring, grip neck,
expanding, stemless & more). Stems tend
to be a weaker mounting solution because
it utilizes one area as opposed to many.
Larger diameter stems tend to be stronger
than smaller ones. Correct installation
of a stem caster is essential for
preventing f uture damage. A correctly
installed stem will expose no part of the
stem & shouldn't be visible underneath an
object. 

Types of Swivel

Swivel Rigs

Swivel Rigs give you the ability to
move an object in any direction.
This is due to swivel section. The
swivel section is the part of every
swivel rig where the mounting
solution (plate or stem) is connected
to the forks (where the wheel sits in
between) & allows the rig to swivel.
The swivel section can be a point
of f ailure because it's a moving
part that has to hold the rig
together while bearing weight on
top of it. Depending on how the rig is designed, the swivel section may have the ball
bearings exposed. Exposed ball bearings can rust making it much harder for the
caster to swivel. Swivel seals can prevent these future issues. 

There are two types of swivel rigs. Kingpin swivel rigs use a kingpin (like a
skateboard truck) to hold the rig together. Kingpinless swivel rigs are rigs that don't
utilize a kingpin to hold the rig together. Kingpinless swivel rigs tend to last
longer than kingpin swivel rigs because the kingpin can stretch over time causing
the ball bearings to fall out.  

Rigid Rigs

Rigid rigs provide direction & keep
things straight during transit. An
object that utilizes a rigid caster may be
difficult to maneuver through tight
spaces. Rigid rigs are typically paired
with swivel rigs, but that's not always the
case depending on the caster set up.  https://mappcaster.com/blogs/news/caster-configuration-how-to-configure-your-cart
They tend to out live their matching
Swivel Rigs due to the fact that there are
no moving parts on a rigid rig. Rigid rigs
almost exclusively have a plate for a
mounting solution with the rare exception
of a stem. 

Rig Capacity

Rigs play a large roll in caster capacities. Caster capacity is primarily determined by
wheel capacity & rig capacity. The official capacity is based on which component
carries the least amount of weight. 

When it comes to swivel casters, the kingpinless rig tends to carry more
weight than a kingpin rig due to the stonger swivel design. The sheer size of the
swivel section (regardless of Kingpin or kingpinless) also plays factor in
capacity as bigger swivel section typically offer more capacity. The
kingpinless design of the rig typically comes at a premium cost which is why some
settle for a swivel caster that uses a kingpin (which is the most common).          Rigid
rigs In some cases will have a higher capacity than their matching swivel rigs. Rigid
rigs are one solid piece as compared to a swivel rig that has multiple pieces & the
swivel section being an inherit weak spot.

Wheel location also plays a big part
in the casters capacity. When the wheel
is positioned closer to the center of
the rig, you get more capacity. This is
why many jack caster's wheels are located
closer to the center. The further out the
wheel is out from the center of the caster,
the more stress there is on the swivel
section & the capacity is reduced overall.
On the other hand, the f urther out the
wheel is f rom the center of the caster,
the easier it is for the swivel caster to
pivot.

The selection of stem casters becomes limited when capacities required exceed
over 700 lbs per caster. Plates are the most common mounting solution when
high capacities are required. 

Longevity

Rigs play a large role in the life span of your caster. Less moving parts or none at all
can give a caster a longer just like rigid rig. If you have a swivel caster, kingpinless
will generally last longer due to the better designed swivel section

Another thing to consider is the environment. When it comes to heat, the rigs
alone can handle heat generally around 600° F unless they have a swivel seal
which might lower the temperature rating. In general, casters living in a high
heat environment have to be chosen carefully because you have to be mindful of the
all individual temperature ratings of each component in the caster.

Water & chemicals are tough on rigs (casters in general) & can cause rust.
Swivel seals can help prevent liquids from entering the ball bearings & rusting them,
but can't prevent rust to other areas. The composition of the rig must be changed in
order to prolong rust. We recommend using a casters that uses a stainless steel rig for
wet environments. Stainless steel can extend the life of your caster, but that comes a
premium cost. When it comes down to deciding if stainless steel is right for you,
consider the downtime, labor required, cost of the rigs & how often this has to be
done. 

Rig Accessories

Swivel Seals

Swivel section seals are designed to
protect the ball bearings of a
swivel rig f rom dirt, liquids &
debris. A swivel section that utilizes a
sealed doesn't swivel quite as well as a
rig without a seal. You sacrifice
the rig's swiveling ease at the cost or
protecting the ball bearings. 

Swivel Locks

Swivel locks give you the ability to
turn your swivel casters into rigid
casters. Rigid casters help provide
direction to whatever you moving &
are recommended for large open
area uses. An all swivel caster set up is
ideal for tighter spaces that may be
hard to maneuver. Swivel locks give
you the best of both worlds. For more
information on how to set up your
casters click here.  https://mappcaster.com/blogs/news/caster-configuration-how-to-configure-your-cart 

Final Thoughts

When it comes to picking a caster out, consider the type of rig you need for
your application. If you have any questions or perhaps need help getting your
hand truck going, give us a call at 713-227-1144 or contact us & we would be
happy to help

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