[CR]Re: ceramic balls


In-Reply-To: <MONKEYFOODRDT6Z3Lst00000c30@monkeyfood.nt.phred.org>
References:
From: Richard Risemberg <rickrise@earthlink.net>
Date: Sat, 4 Aug 2007 08:00:41 -0700
To: classicrendezvous@bikelist.org
Subject: [CR]Re: ceramic balls

On Aug 4, 2007, at 7:31 AM, classicrendezvous-request@bikelist.org wrote:
>
>> Hullo,
>> One could replace all the ball bearings in a SR/NR group will
>> ceramic balls. I bit of the best of both worlds.

Yes, the high cost of cartridges with the preload-induced higher friction of cup-and-cone!

This made me read up a bit on ceramic bearings, and they don't seem to be BS. They're just cartridge bearings where the balls or rollers and sometimes the races are made of silicon nitride ceramics. They use the ceramic because it's harder and smoother than the usual steel, resulting in less friction. Same reason you'd choose grade 25 steel bearing balls over grade 300 steel bearing balls. The purpose of a bearing is, after all, to reduce friction--isn't it? I don't see anyone touting the benefits of tallow-soaked leather bearings, though they were the technology of choice in their time.

Rick "what about tapered roller cartridge bearings that let you adjust preload just as C&Cs do?" Risemberg -- Richard Risemberg http://www.bicyclefixation.com http://www.newcolonist.com http://www.rickrise.com