Caster Bearings

January 29, 2021

Bearing's have a specific function assisting whatever sits on them or what they sit
inside of roll. There are 2 types of bearings, mechanical & non-mechanical.  When it
comes to casters, there are  5 main options of bearings to choose from, roller
bearings, ball bearings, tapered bearing, delrin bearing & brass bearings. Each
bearing has its own benefit to them ranging from cost effectiveness, ease of rolling,
able to withstand high speeds, resistance to high temperatures, water & chemicals.
Often times these bearings are used together with a spanner bushing to reduce the
inside diameter of the bearing & ultimately give the wheel a secure fit

Mechanical Bearings

Roller Bearings

The roller bearing is one of the most common types of bearings used in casters. This
barrel shaped bearing uses needle like rollers that expand throughout the hub length
to distribute weight & assist with rolling. The roller bearing is a step above a bushing
in terms of offering assistance with rolling.

The caged roller bearing is a heavier duty roller bearing that has everything
captured in one piece. Caged roller bearings don't require thrust washers (which must
be used for regular roller bearings) to hold this bearing within your wheel. Caged
roller bearings are an exceptional choice for casters that will move continuously in
one direction. For example, regular roller bearings used in a pallet wrapping machine
run the risk of the bearing's sleeve cutting through the thrust washer & even cut into the
rig because it makes circles continuously around pallets. 

Roller bearings are great for many applications but, we do not recommend this
type of bearing for high speed applications

Roller bearings must use thrust washers (with the exception of caged roller
bearings) to keep the bearing from moving side to side within the hub. These
thrust washers help seal the bearing from the elements while retaining the grease
within the caster's wheel. Plastic thrust washers are the most common type of
washers used in caster wheels & provide a great seal. Plastic thrust washers are
commonly paired with stainless steel roller bearings for wet applications. Metal
thrust washers are recommended for high temperature applications where plastic
thrust washers would melt. Metal internal thrust washers are also ideal for hot
applications, but they reside within the wheel to make the overall hub length of
the wheel smaller. Neoprene internal thrust washers also reside in the hub of the
wheel & offer a superior seal. 

Ball Bearings

Ball bearings are recommended for
applications where you want the
least amount of resistance
moving an object. Ball bearings are
the quietest bearing option for
those who are conscious of
noise. Most ball bearings are sealed
& require no maintenance.
Depending on the ball bearing used
inside your wheel, the bearing may
use a spanner to reduce its inside
diameter to fit on your caster. Some higher end ball bearings may use a a top hat
spanner bushing (looks like a top hat) to reduce the wheels inside diameter to fit
correctly on a caster. Just like the roller bearings, there are stainless steel ball
bearings that are able to withstand wet environments & high temp ball bearings that
can withstand high temperatures. 

Tapered Bearings

Tapered bearing can be found in
several everyday objects like the
vehicle you use to drive, tractors,
trains, gearboxes & much
more. Tapered bearings are designed
to reduce friction which overall
reduces heat. This bearing are
incredibly durable & are designed to
roll for miles. In the caster world,
tapered bearings aren't as common.
Casters that use tapered bearings
usually are carrying extreme capacities or being used in some caster that is being
moved at high speeds. Tapered bearings are available in stainless steel options as well
as options that are catered to high temperature applications.

Non-Mechanical Bearings

Bushings are a type of bearing, but not all bearings are bushings. As previously
stated, bearings have a specific function to assist whatever sits on them or what they
sit inside of to roll. Customers tend to use bushings in their caster wheels for primarily
2 reasons, water/wet applications & heat.

Delrin Bushings

Delrin bushings are an economic alternative to stainless bearings that are ideal
for
wet environments, Delrin bushings offer fuel, solvent & superior
impact resistance. Delrin is also an economical choice to roller bearings. The
only caveat to this resin bushing is that it will be a bit harder for you to move you
casters since there isn't any moving parts like a mechanical bearing.

Delrin bushings can come in a one piece configuration or a two piece
configuration. A one piece delrin bushing usually extends the entire hub length of
the wheel & usually blocks the grease channel of a wheel. One piece delrin
bushings are
typically greased from the axle, if your caster's axle has a grease fitting.

A common two piece combination has two bushings pressed into the both
sides of the wheel. The benefit of using this configuration is that it allows you to
grease the bushing from the wheel where a once piece delrin would seal the
grease channel. The down side of using this two piece combination is that if these
caster wheels are being submerged in water, there's a cavity between these two
bushings that can fill up & retain water. Another type of two wheel combination
uses a one piece delrin bushing & typically a delrin spanner. This spanner extends
a bit further in length to give room for the wheel when axle is tightened all the way.
This combination is typically greased from the axle. 

Brass Bushings

Brass bushings are specifically designed for high temperature applications. Brass
bushings can be plain old brass or even be self lubricating to help assist with
rolling. Graphite is often used in brass bushings to help with rolling. Some brass
bushings are able to withstand temperatures up to 1300°F. Just like the delrin
bushings, there are two piece options available that would be pressed in on both
sides of the wheel & has a flange that keeps its from being press in too far. The two
piece bushings tend to lengthen the hub length a bit. Depending on your specific
caster, it may need a spanner to reduce the inside diameter of your wheel to fit
properly on to your caster.

Choosing the Right Bearing for You

When it comes down to choosing a bearing, consider your application. Hot
& wet applications are among the roughest applications on bearings. The
amount of exposure to one or both of these types of applications should also be
considered. Failure to consider your application can lead to premature failure
of the bearing. This can cost you in term of replacing your bearings more often
than needed & cost you in the amount of time needed to get your casters functioning
as it should. Lastly, consider your budget. Ask yourself is this extra cost worth
benefits you are receiving? No situation is exactly the same.

Final Thoughts

 If you have any questions
about your application? Ask a caster expert & gain some insight on the bearing that's
right for you, feel free to contact us or give us a call at 713-227-1144. 

Link to Bearings options

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