Junior Member
So i am rebuilding my bottom bracket on an old beater bike so i can have a back up in case my current one decides to go kaput on me. I already have a replacement spindle i picked up for 5 bucks used. The BB on the other hand came caged but those cages literally disintegrated but the bearings look to be in decent shape. I called a LBS seeing if they have any cages i could get for the bearings, but the guy told me not to even use caged bearings and just use the bearings by themselves. I have never replaced bearings on mine or a friends bikes without cages.
So my question is will it be fine to just use the bearings with no cages or should i try and find some from somewhere?
So my question is will it be fine to just use the bearings with no cages or should i try and find some from somewhere?
Senior Member
Those "cages" (aka "retainers") are not necessary and are used by bike manufacturers to speed assembly, not because they are beneficial in any other way. You can indeed replace the bearing balls without them. However, you will need one or two additional balls per side to fill the extra space. Take the adjustable cup and add bearing balls to completely fill the race, then remove one and use that number on each side. I recommend placing a ring of grease around each cup before final assembly to hold the balls in place and then cover the balls with extra grease while you install the cups and spindle.
Junior Member
Quote:
Originally Posted by HillRider
Those "cages" (aka "retainers") are not necessary and are used by bike manufacturers to speed assembly, not because they are beneficial in any other way. You can indeed replace the bearing balls without them. However, you will need one or two additional balls per side to fill the extra space. Take the adjustable cup and add bearing balls to completely fill the race, then remove one and use that number on each side. I recommend placing a ring of grease around each cup before final assembly to hold the balls in place and then cover the balls with extra grease while you install the cups and spindle.
Perfect! Thanks for such a quick answer. Is adding the one or two BB's necessary? I only have what they came with and don't want to have to go buy another set of BB's from the LBS since they only sell them in packs.
FBinNY
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+1, except that you need to be very careful about the assumption that they'll need or even accept additional balls. Many retainers used for bicycles, do not reduce the number of balls compared to a full complement of loose balls. You can sort of tell by whether the balls in the retainers are close to touching each other or separated bu the space of half a ball or more.Originally Posted by HillRider
Those "cages" (aka "retainers") are not necessary .... However, you will need one or two additional balls per side to fill the extra space. ...
Keep in mind that a single ball too many is a disaster (in bearing terms) while one too few is easily tolerated. A correct count of loose balls will typically have space that deceptively looks like another will fit.
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Keep in mind that a single ball too many is a disaster (in bearing terms) while one too few is easily tolerated. A correct count of loose balls will typically have space that deceptively looks like another will fit.
Originally Posted by FBinNY
+1, except that you need to be very careful about the assumption that they'll need or even accept additional balls. Many retainers used for bicycles, do not reduce the number of balls compared to a full complement of loose balls. You can sort of tell by whether the balls in the retainers are close to touching each other or separated bu the space of half a ball or more.Keep in mind that a single ball too many is a disaster (in bearing terms) while one too few is easily tolerated. A correct count of loose balls will typically have space that deceptively looks like another will fit.
Right on. So i can use what i got and get by with little to no problems. Thanks so much for the quick replies guys!
Senior Member
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Keep in mind that a single ball too many is a disaster (in bearing terms) while one too few is easily tolerated. A correct count of loose balls will typically have space that deceptively looks like another will fit.
Correct, which is why I recommended the OP fill one race with a full compliment of balls and see if there is room for more or if the old number is sufficient. I recall cup-and-cone bottom brackets that had 7 caged 1/4" balls per side but took 9 easily when the retainer was discarded. YMMV. Originally Posted by FBinNY
+1, except that you need to be very careful about the assumption that they'll need or even accept additional balls. Many retainers used for bicycles, do not reduce the number of balls compared to a full complement of loose balls. You can sort of tell by whether the balls in the retainers are close to touching each other or separated bu the space of half a ball or more.Keep in mind that a single ball too many is a disaster (in bearing terms) while one too few is easily tolerated. A correct count of loose balls will typically have space that deceptively looks like another will fit.
BTW, to the OP: Good quality (Grade 25 is most often used) bearing balls are quite inexpensive, even in bags of 25 or 100. Since this bike is old and the retainers have fallen apart, it would be worth the minor cost to use all new balls.
Junior Member
Quote:
BTW, to the OP: Good quality (Grade 25 is most often used) bearing balls are quite inexpensive, even in bags of 25 or 100. Since this bike is old and the retainers have fallen apart, it would be worth the minor cost to use all new balls.
Thanks for the advice! I will try to make it down to the LBS when i get the chance.Originally Posted by HillRider
Correct, which is why I recommended the OP fill one race with a full compliment of balls and see if there is room for more or if the old number is sufficient. I recall cup-and-cone bottom brackets that had 7 caged 1/4" balls per side but took 9 easily when the retainer was discarded. YMMV. BTW, to the OP: Good quality (Grade 25 is most often used) bearing balls are quite inexpensive, even in bags of 25 or 100. Since this bike is old and the retainers have fallen apart, it would be worth the minor cost to use all new balls.
Senior Member
BTW, i've bought single ball bearings of appropriate size, at the local Ace Hardware. and if you find them, buy a couple extra, you may have need of them if and when you find out first-hand why and how effective those cages are in assembly.
i think i can remember dropping a few bearings down the seattube and up the downtube, only to lodge in there for a few months. the extra grease i had on them permitted them to hang on to the walls of the tube, longer than i imagined they could. then they started rattling around in the BB.
i think i can remember dropping a few bearings down the seattube and up the downtube, only to lodge in there for a few months. the extra grease i had on them permitted them to hang on to the walls of the tube, longer than i imagined they could. then they started rattling around in the BB.

Junior Member
I biked down to the LBS (only a couple miles away) and happened to talk to the manager on shift which was a great guy. I was able to purchase a new set of BB's, 18 in all. For a couple bucks from him. Got back to my place and was able to install everything within 10 minutes.
I would like to thank everybody for the advice given. Definitely good help around here.
Much appreciated, Tyler Tucker
I would like to thank everybody for the advice given. Definitely good help around here.
Much appreciated, Tyler Tucker
Quote:
One wonders then, why most cartridge bearings which are not assembled by bike manufacturers also use cages.Originally Posted by HillRider
Those "cages" (aka "retainers") are not necessary and are used by bike manufacturers to speed assembly, not because they are beneficial in any other way. . .
NASA has a different opinion:
"Ball and roller bearing separators, sometimes called
cages or retainers, are bearing components that, although
never carrying load, are capable of exerting a vital
influence on the efficiency of the bearing. In a bearing
without a separator, the rolling elements contact each
other during operation and in so doing experience severe
sliding and friction. The primary function of a separator
is to maintain the proper distance between the rolling
elements and to ensure proper load distribution and
balance within the bearing. Another function of the
separator is to maintain control of the rolling elements in
such a manner as to produce the least possible friction
through sliding contact."
The universe has a few more dimensions than most posters here can guess.
FBinNY
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...
The universe has a few more dimensions than most posters here can guess.
Yes, the retainer/separator issue is a bit more complex than most believe. For example, most radial cartridge bearings a re totally dependent on separators to work. The balls are loaded all on one side while the inner race is off center, then the race is centered, the balls spread around, and the separators added to keep it that way. Here's a video that shows the sequence of assembly (manually). Of course this is done much faster by machine.Originally Posted by AnkleWork
One wonders then, why most cartridge bearings which are not assembled by bike manufacturers also use cages....
The universe has a few more dimensions than most posters here can guess.
Separators also serve the function of eliminating ball to ball contact, but in a decent bearing there wouldn't be much anyway, and what happens would be at very low contact pressure compared to the loads (though axle drop can change that), but these separators are made of softer alloys, usually porous bronzes which can also provide lubrication as the balls rub past them.
However the retainers used on most bicycle bearings serve neither function, and are mainly an assembly convenience. If you look at an equal quality component group from a single manufacturer, ie Shimano Dura Ace, you'll see that they use loose balls for factory assembled parts like hubs and pedals, but use retainers on headsets and bottom brackets that must be assembled onto a bicycle by their OEM clients.
So, it's a matter of the details, not a one size fits all answer.
JohnDThompson
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Close. Most use 9 1/4" balls, but 11 will fit. Better quality bottom brackets came with 11 ball retainers. You won't be able to fit any more into a typical bottom bracket that uses 1/4" balls.Originally Posted by HillRider
I recall cup-and-cone bottom brackets that had 7 caged 1/4" balls per side but took 9 easily when the retainer was discarded.





