Re: [CR]bb ball retainers


Date: Tue, 17 Jul 2007 19:18:10 -0400
To: Bianca Pratorius <biankita@comcast.net>, classicrendezvous@bikelist.org
From: Sheldon Brown <CaptBike@sheldonbrown.com>
Subject: Re: [CR]bb ball retainers


I had previously sent this with some formatting setting off the quoted section, but that doesn't seem to have worked so well with the mailing list software. ============================================== Quoth Garth Libre:
>I thought that the one place where ball retainers was acceptable was
>in a bottom bracket because the balls are easy to lose down the
>chainstay and difficult to place with your finger if you already
>screwed in the fixed cup.

If you have a bottom bracket sleeve of some sort (and you ALWAYS should with a loose-ball BB) there's no possibility of losing balls down the chainstay.
> I just installed a brand new old stock high end Italian bb using
>the retainer because: 1) I was too lazy to go out and get a full set
>of balls (bearings that is) 2) I didn't want to lose any balls which
>in the past I have done and had to take it apart to get to the noisy
>ball.
>
>To my surprise there is a touch of something I don't like with the
>retainer. The shell is nicely faced so that's not it. The crank
>still spins nicely but you can feel that there is room for
>improvement. How many people use the retainer on their personal
>bikes? Is it sacrilege or just in bad form?

How many balls? A very few retainers have a full complement of 11 balls. Those are the ONLY retainers I would ever consider using in a bottom bracket.

It really isn't difficult to assemble a BB with loose balls. Here's an excerpt from http://sheldonbrown.com/tooltips/bbadj.html : ==============================================

Use Loose Balls Most newer bicycles come with "caged" bearing balls-the balls are held in a metal or plastic retainer. This makes it easier to install the balls, but usually at a cost in performance. A standard three-piece type bottom bracket takes 11 loose 1/4-inch balls per side. Most retainers hold fewer balls, so each ball and its contact points with the cup and cone are more heavily stressed. This causes higher friction and more rapid wear. If your bottom bracket came with retainers holding fewer than 11 balls, I strongly recommend that you replace them with loose balls. This is not really difficult to do. if you know how. The frame should be lying on its right side, with the fixed cup and liner installed. Squirt plenty of grease into both cups. Set 11 balls into the adjustable cup. Drop the shorter end of the spindle into the cup, and it will hold the balls in place even if you are using a thin grease. Holding the adjustable cup and spindle as a unit, turn them over so that the cup is on top. Set this assembly aside in this position, supported by the spindle. (A convenient place to put it temporarily is into the right crank: the chain wheel will prevent it from falling over.) Next, stick a finger up through the hole in the fixed cup to keep the balls from falling through. Drop 11 balls down into the cup and arrange them in a circle around your finger. Then, pick up the spindle (with the adjustable cup already installed) and lower it down until it rests on the finger that is sticking up through the fixed cup. Lower it farther, until you can begin to screw the adjustable cup into the bottom bracket threads. Keep the spindle supported from below until the adjustable cup is screwed well in, because if you release the spindle while the cup is very loose, the balls may fall out of position.

Don't Mix Balls Don't try to reuse some of the balls from your retainer-it is very important that all of the balls in a race be from the same production lot so that they will all be the same size. Good quality bearing balls from a given lot will usually be within two or three millionths of an inch of each other in size, but if you mix lots the difference can easily be 25 or 30 millionths. If there is this much difference in size, the smaller ones might just as well be missing for all the good they will do! ==============================================

Sheldon "Retainers Only For Headsets" Brown +------------------------------------------------+ | Love at its best means marriage, and it is | | altogether the most beautiful thing in life | | -- William Dean Howells | +------------------------------------------------+ --
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