Thought this e-mail could generate some discussion about sealed ceramic bearings. It is from Bill Riggins who sold me separate ceramic balls for the diffs on my XXX-S. Here goes...
Bill D
the original group of racers (who pooled funds to buy the unsealed ceramic ball bearings in bulk) have checked into the sealed ceramic. I posted basically what the group found about them on the Starting Grid (copied below). In short, without paying for bearings certified by an ITL (independent test lab) you could get great bearings or you could get crap. Since high quality standard sealed are only $1 each we’ve decided to stick with them for the time being.
Bill R
#1225 of 2156 by Bill R (zoomadic) on Thu Feb 26 02:41:28 2004:
What we've found with the non-sealed ceramic ball bearings is that there are -vast- differences in quality even among the highest grade bearings. The durability differences are caused by different binder (the material in the bearing that is not silicon nitride) and/or a different manufacturing process.
We've only tested grade three balls (the best available) and only two manufacturers (of eleven tested so far) have held up really well. The one we have been ordering from in bulk for the past three years has a zero failure rate and is much much more durable than carbide. The thrust bearings need to be replaced occasionally but some regular racers have been using the same diff balls for years. I know that is hard to believe for those using carbide but some ceramic bearings really are that durable. But then, it bears mention that none of the samples from US manufacturers tested well, and more than one racer had the grade three bearings from Salem and Hoover (both large US makers) actually powderize (disintegrate)
during use.
Jim a couple of the racers that bulk order the ball bearings have tested ceramic sealed bearings in clutches and wheels but not engine bearings yet. One of the things we found when looking into sealed ceramic bearings is that a lot of the sealed bearings being sold as "ceramic" actually only use 1/2 ceramic balls (every other ball). This technique is used since the bearings last almost as long as a bearing with all ceramic balls and it obviously cuts the cost. I have also been told by the manufacturer we purchase balls from that ceramics work best in the smaller sealed bearings (like we use) in a high ABEC "deep groove" format. This would be where they ride in a tight tolerance grooved race instead of on a flat race. There were more that I don't remember, but the two primary reasons given are that ceramic balls don't expand like carbide balls do and the ceramic balls are more durable. We just haven't had that much of a problem with standard sealed bearings so haven't ordered any of the ceramic sealed in bulk.
Bill R
--------------------------------------------------------------------------------
From: "Bill Deras"
Date: Wed, 14 Apr 2004 18:37:01 -0700
To: "Bill Riggins" <
[email protected]>
Subject: RE: Ceramic Bearing Set question
Bill R,
Do you have any recommendations for a complete set of sealed ceramic bearing (19 or 23) for my XXX-S?
And thanks again.
Bill D