which way do these ringed-bearings go in a bmx-style bb?
Charlie Laidlaw
i've taken apart my girlfriend's old beater of a bike ('Vantage').
It turns out not to have a proper bottom-bracket, but the cranks are
connected ('bmx style'?).
Anyway, i've taken it all apart, cleaned it up and liberally smeared
lithium grease around, but i've messed up the orientation of the
bearings (which are contained in a sort of ring-cage thingie). Which
way do they go in? On one side the ring has somewhat of a 'backing'
or a wall, on the other, the bearings face outwards. It would seem to
fit in either way....
also, i found that when i did put it together and tightened it up, if
it tightened too much, the cranks got too stiff to turn smoothly, but
too loose and then the cranks 'wiggled'. Just gotta find the sweet
spot i guess, then tighten up the outer locking-nut?
cheers,
charlie
Hugh N. B. Flynn
Your girlfriend's bike has what is called a one-piece or ashtabula crank
see:
http://sheldonbrown.com/gloss_m-o.html#opc
or
http://sheldonbrown.com/gloss_a.html#ashtabula
The bearing retainers you mention are intended to go into the bottom
bracket cups with the 'flat' side facing the cup and the bearing side
facing out (to better engage the cones on the cranks).
The bearing/retainers are inexpensive so, go to your local bike shop and
buy some new ones before you put the bottom bracket back together. Since
one piece crank bottom bracket bearing retainers come in two sizes, it
might not be a bad idea to bring one of the old ones to the bike shop
with you.
Hugh Flynn
Amherst, MA.
Charlie Laidlaw wrote:
--
Hugh N. B. Flynn
Amherst MA
hug...@student.umass.edu
BQinMD
The cone goes in from the side with the cage (backing) on it. This pushes the
balls out so they can contact the cup. If you put it in backwards, the cage
will get caught between the balls and the cups (ouch!) and make it impossible
to adjust properly. IOW, the cage should be toward the outside of the bike.
Look at it and it will make sense. If the bearings are properly installed, you
should be able to find the "sweet spot" easily. Keep in mind that tightening
the locknut might cause the adjustment to tighten up - play around with the
adjustment until you get it just right. The same rule of thumb applies to all
caged bearings. Good luck.
Bill Yoder Harford County, MD USA
A Muzi
upside-down bearings last month. I teach my guys to fit the bearing dry
in the cup (no crank), turn the cone on it, and then reverse the bearing
and try it again. Once you take a moment to actually look and feel the
bearing both ways you'll never flip one over again. When you've got the
assembly clean once more, take a moment to look at the bearing surfaces.
Is there a nice thin shiny silver line where the bearing ran? If the line
is broken, uneven or pitted, get the complete asembly (cups, cones,
washer, lockring, bearings). They are under $10. Inability to find a
smooth adjustment between tight and loose indicates probable wear/damage.
Charlie Laidlaw wrote:
> hi, i need some newbie-mechanic advice:
>
> i've taken apart my girlfriend's old beater of a bike ('Vantage').
> It turns out not to have a proper bottom-bracket, but the cranks are
> connected ('bmx style'?).
>
> Anyway, i've taken it all apart, cleaned it up and liberally smeared
> lithium grease around, but i've messed up the orientation of the
> bearings (which are contained in a sort of ring-cage thingie). Which
> way do they go in? On one side the ring has somewhat of a 'backing'
> or a wall, on the other, the bearings face outwards. It would seem to
> fit in either way....
>
> also, i found that when i did put it together and tightened it up, if
> it tightened too much, the cranks got too stiff to turn smoothly, but
> too loose and then the cranks 'wiggled'. Just gotta find the sweet
> spot i guess, then tighten up the outer locking-nut?
>
> cheers,
> charlie
--
Yellow Jersey, Ltd
http://www.yellowjersey.org
http://www.execpc.com/yellowje
Open every day since 1 April, 1971
Charlie Laidlaw
your instructions to face the bearings out makes sense, but
unfortunately i've also recieved the exact opposite advice in this
thread...part of the wonder of newsgroups!
"The cone goes in from the side with the cage (backing) on it ... IOW
the cage should be toward the outside of the bike."
cheers,
charlie
On Mon, 20 Nov 2000 06:22:54 -0500, "Hugh N. B. Flynn"
<hug...@student.umass.edu> wrote:
>Hi Charlie -
>
>Your girlfriend's bike has what is called a one-piece or ashtabula crank
>...
>The bearing retainers you mention are intended to go into the bottom
>bracket cups with the 'flat' side facing the cup and the bearing side
>facing out (to better engage the cones on the cranks).
>
>The bearing/retainers are inexpensive so, go to your local bike shop and
>buy some new ones before you put the bottom bracket back together. ..
>Hugh Flynn
>Amherst, MA.
jeffslotkin
constructed is different for different applications, but for one piece
cranks they will keep the bearings from touching the races if they are
installed balls-out (also known as flat side in).
--
Jeff Slotkin
TheLoc...@bigfoot.com
"Hugh N. B. Flynn" <hug...@student.umass.edu> wrote in message
news:3A19098E...@student.umass.edu...
(snip)
> The bearing retainers you mention are intended to go into the bottom
> bracket cups with the 'flat' side facing the cup and the bearing
side
> facing out (to better engage the cones on the cranks).
(snip)
Charlie Laidlaw
thanks Bill,
i _think_ this makes more sense than the alternative...which another
giver-of-advice has recommended.
-ta,
charlie
Charlie Laidlaw
wrote:
hey, i think this will settle it for me! thanks muchly, i'll
investigate as you've suggested
Hugh N. B. Flynn
Sorry about that. Looks like I'm a bit turned around on this one.
Hugh "Which Way?" Flynn
jeffslotkin wrote:
--
Jim Adney
>Anyway, i've taken it all apart, cleaned it up and liberally smeared
>lithium grease around, but i've messed up the orientation of the
>bearings (which are contained in a sort of ring-cage thingie). Which
>way do they go in? On one side the ring has somewhat of a 'backing'
>or a wall, on the other, the bearings face outwards. It would seem to
>fit in either way....
The races here consist of a cup and a cone. The "wall" on the bearing
retainer faces the cone and the round bearing side faces the cup.
If you put them in backwards they will fit, but the balls won't be
free to roll.
-
-----------------------------------------------
Jim Adney jad...@vwtype3.org
Madison,Wisconsin USA
-----------------------------------------------
Jim Adney
>I'm afraid Hugh has this backwards. The way the retainers are
>constructed is different for different applications, but for one piece
>cranks they will keep the bearings from touching the races if they are
>installed balls-out (also known as flat side in).
I think THIS is backwards. On a 1-piece crank the cones are on the
outside and the flat side should face out.
In general, the flat side of a bearing retainer faces the cone, not
the cup.