Sealed BB, was: Re: [CR]OMAS??

(Example: Framebuilding:Technology)

Date: Sun, 10 Aug 2003 18:43:15 -0400
From: "HM & SS Sachs" <sachs@erols.com>
To: steve@sburl.com, classicrendezvous@bikelist.org
Subject: Sealed BB, was: Re: [CR]OMAS??


Stephen Barner wrote about bad experiences with some OMAS and Edco BB, and concluded:

In the early '80s, I tried the sealed OMAS bottom brackets--two of them. Both suffered premature failure after a little over a season, due to water penetration, with the bearings freezing solid. Even though I had liberally greased the aluminum cups, I had a bear of a time getting them out, as galvanic reaction had practically welded them into the frame. I still have both trashed BBs in my junk archives.

I also had a bad experience with an Edco BB. I was doing my 20 mile ride home from work and noticed something odd in the cranks. Ten miles later, the bearings on one side had broken up and were completely gone. I've seen standard BBs go hundreds, perhaps thousands of miles all pitted up, but still turning. I decided then and there to never use sealed mechanisms on a tour (kind of like why you should not use rechargable batteries in the flashlight you keep in the car). You want parts that can get you back to civilization. Phil Wood stuff has such an excellent reputation, I would consider it an exception, unless someone out there has any failed-Wood-on-the-road hard luck stories to share.

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A couple of notes may be helpful: 1) Some Phil (and other) bb use standard cartridge shielded bearings, which can be gotten from bearing houses at a reasonable price. Overnight if worst-comes-to worst. Others use dedicated assemblies, meaning that on-road replacement requires finding an equivalent assembly, probably the whole bb assembly.

2) The right side of some sealed bearing rear hubs is Trouble. Specially-sized and rather expensive bearings. This was true, for example, of the Off-Topic Sachs 7-speed road cassette hub.

Having said that, I've used cartridge/sealed bearings where-ever feasible on my daily rider bikes for a couple of decades now. One less thing to worry about for my riding, but I am not doing long un-supported tours.

harvey sachs
mcLean va