Ceramic Bearings are not better than steel ones.

6 07 2008

This is where, in a perfect world everyone would take a simple engineering course so they would know what they are actually buying into.

All bearings have their place.   Ceramic bearings are now all the rage and although I don’t mind if you get them you really should know that they do not have any less rotational drag than traditional steel ball bearings.

Ball bearings have an  ABEC rating and have all sorts of specs like sealed, what types of seals, what types of lubrication, what types of casings and what types of bearings.   The possibilities are enormous.

Here is the down low.   Ceramic and steel ball bearings of equal specification will act exactly in the same manner.   There would absolutely be no difference in performance of these two theoretical bearings.   Often what some may perceive as a difference is only that they are replacing a low quality steel bearing with a high quality ceramic bearing, nothing more.

Ceramic bearings are made for high temperature applications where steel bearings my fail (think turbo chargers)  Steel bearings are available for extremely precise application all the way up to ABEC 9.   For instance, I had to replace my lathe bearings.  Very traditional 2” diameter bearings except that because of their specification cost $800.00 dollars.

Ceramic bearings may weigh a touch less than their steel counterparts but claims of better concentricity, durability, strength and lower friction is just not true.

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Here is a tidbit from Boca Bearings.  A producer of Ceramic bearings:

Ceramic is the ideal material for any application operating in harsh environments where extreme temperatures and corrosive substances are present. Ceramic has 35 percent less thermal expansion, 50 percent less thermal conductivity, are lighter weight and are non-corrosive.

Applications:
Cryopumps, medical devices, semiconductors, machine tools, turbine flow meters, food processing equipment, robotics and optics.

About Boca Bearing:
With over 3000 different bearing sizes and well over three million bearings in stock, Boca Bearings offers the largest stock of replacement bearings for all industrial, medical and specialty applications.

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What they say is absolutely accurate.   Notice, they did not say they have less resistance or are tougher.  I would consider bicycles not to be an environment of extreme temperatures or involved with corrosive substances.  Machine tools, Cryopumps, turbopumps etc all go through conditions that are more severe than any bicycle part.   As you may have ascertained.  They are certainly not going to hinder you.  They just are not going to do anything for you either.

I will also add that even if one theoretical bearing  had 10% less frictional losses than another example  that frictional losses from bearings in a bicycle are so low as to make this measurement inconsequential.   Those that can “feel” it are experiencing the placebo effect in all it’s glory.

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One response

31 12 2013
Renuka

The steel ball bearings have bearing weight capacity in high but ceramic is not enough for that. It is only used at high temperature applications. But steel bearings are applicable in applications except the high temperature only.

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