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The ball bearings we use in our skates are made up
of several parts and pieces:
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The
inner and outer race
(made from steel).
The
balls
(generally made from steel).
The
cage
(made from different materials including nylon,
plastic and steel, to keep the balls spaced properly
around the bearing).
The
shields
(which act to keep the dirt and dust
(or in the case of the speed skaters, road kill) out of the bearings).
ABEC Ratings:
The ABEC number you hear everyone talking about, refers
to the tolerance (precision) with which a particular
bearing is manufactured.
Those tolerances were established by the
Annular Bearing Engineers Committee of the
American Bearing Manufacturing Association.
The idea is: the higher
the number (rating), the greater the manufacturing
precision, and theoretically, the smaller the amount of
friction. By the way, the
International Organization
for Standardization (ISO) rates bearings the opposite way; the
SMALLER the rating number, the higher the manufacturing precision.
Ceramic Bearings:
In a ceramic bearing the steel balls are replaced
with balls made from ceramic.
There are essentially two types of ceramic bearings:
-
Bearings which have ALL the steel balls replaced with ceramic balls.
-
Bearings which have every other steel
ball replaced with a ceramic ball.
These bearings are sometimes called a "hybrid"
and are generally much less expensive than the first type though
they may still be advertised as " ceramic bearings".
The "advantages" of a ceramic bearing?
-
The ceramic is harder than steel. The idea is that ceramic will
last longer than steel. However, if it is properly maintained
the steel bearing will last longer than YOU anyway so is this really important?
-
In the "all ceramic" version corrosion is less of an issue,
but corrosion or pitting of the rest of the bearing (the steel inner
and outer race) is still an issue, so you gain what?
-
No "arcing". I saw this claim on a recent advertisement for
ceramic bearings and while it is absolutely true of ceramic bearings
you HAVE TO REMEMBER we are skaters. If you are having problems with
"arcing" in your bearings you don't need ceramic bearings, you
need to stop skating around the transformers on the high voltage
lines during your lunch hour at the Nuclear plant! The same is
true of other claims such as lighter weight, cooler running,
no cold welding or galling. All are, in my opinion, while true,
NOT issues that we as skaters need to be concerned with.
-
Your friends will be impressed. If your friends are
impressed with flambouyant outlays of disposable income,
I suggest you get in your new four wheel drive SUV with
the 16 gazillion candela powered off-road lights and drive
down to the local trendy coffee shop and find some REAL
people to hangout with.
-
You will believe you should go faster.
How do you take care of a ceramic bearing?
(The same way you take care of a steel bearing.)
How often should you take care of ceramic bearings?
(Use the same frequency you would use on your steel bearings)
Will you go faster, jump further, meet a nicer class of person
if you use ceramic bearings?
-
Honestly? No. But before you argue....
I am NOT disputing the fact that a ceramic bearing generates
less friction and requires less maintenance than a typical ABEC 3
bearing, in a typical industrial application. However, in highly
technical and mechanical engineering terms:
The total difference in the effort required (the amount of umph)
to perform a certain amount of work (to skate down the road )
with a new steel ABEC 3 bearing verses a "ceramic bearing",
in a real world inline skate application, doesn't amount to squat.
In both cases the bearing is carrying only a small fraction
of its designed weight capacity, and is turning relatively slowly
(a 12 mph skate speed relates to a 1280 bearing rpm (80 mm wheel).
Any reduction in friction by the use of a ceramic bearing
instead of a "normal" ABEC 3 bearing, is more than cancelled
out by the viscosity (thickness) of the specific lubrication used,
and the flex of the wheel hub, frame, and boot during a normal stroke.
Think of it like putting racing slicks on a Moped.
But don't let that stop you.
Some of the biggest factors you can change, about what you take
skating in order to go faster or further, is your mind (see #5 above),
and keeping what ever bearing you use clean and well lubricated.
About the author...
When he is not skating, Kyle Milliken
is a Mechanical Engineer in Atlanta Georgia. He is a member
of the National Skate Patrol and The Atlanta Peachtree Road
Rollers. He does not drive an SUV nor is he willing to pay
$4 for a cup of coffee. He lives with his dog Pogo
whose interest in skating involves eating the
laces out of Kyle's skates.
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