MTB cone type wheel bearings.

On Fri, 19 Apr 2013 14:43:52 +0100, "Ian Field"
wrote:



"J.B.Slocomb" wrote in message
.. .
On Mon, 15 Apr 2013 16:29:15 +0100, "Ian Field"
wrote:



"J.B.Slocomb" wrote in message
...
On Mon, 15 Apr 2013 12:53:37 +1000, James
wrote:

On 13/04/13 08:13, AMuzi wrote:
On 4/12/2013 3:49 PM, Ian Field wrote:
Facing the impending need to replace the back wheel, I
sorted through the 'spares' laying about (all 2 of them) -
one had a good rim (so far so good) both had loose spindles.

Both wheels use caged ball bearings and out of the 2 wheels,
there was only 1 good bearing cage - but between the 2
wheels, there was enough balls to fill one of the grooves
with balls and just a small clearance gap - just like they
did in the old days.

What I was wondering, is there some special reason to use
less ball-bearings with a cage to keep them equal distance
apart - such as the cage is cheaper than a full complement,
or they use lower grade metal, so the ball bearings cant be
allowed to be in contact with the one next to it?

Anyone know the answer?

Retainers save assembly time which is more expensive than standard
grade
bearings. Fewer balls merely add to the designer's savings. Full count
retainers can be of equal quality to regular loose Grade 25 bearings.
Retainers as you describe are usually of poor quality besides being
short count.

Without a retainer, how do the balls stay evenly spaced around the
cup/cone?

I don't think they do. I think they bunch up toward the top, leaving a
gap at the bottom, and because they touch and effectively counter
rotate, there is additional wear and friction between the balls.

Even if the retainer is poor quality, while it lasts it at least
attempts to maintain equal spacing between the balls.

But, if the balls jam together wouldn't they also jam against the
retainer sides?

I assume cartridge bearings have a better quality retainer, or at least
if properly sealed the retainer lasts longer.

Some "cartridge bearings" don't have any retainer...

All the retainers I've seen were very cheaply made and had nasty burrs
that
were tempered along with the component, the cartridge bearings usually
have
a pair of matching shells that clamp together, the only friction is
between
the balls and the smooth recesses pressed into the shells.

If "all the retainers I've seen were very cheaply made" it rather
implies that the retainers are not an important part of the bearing,
doesn't it? After all a bearing that is intended to hold the wheel on
an auto, for example, and that lasts for, say 200,000 Km, and is still
serviceable, and hasn't been greased since it was originally
installed, is likely of at least reasonable quality :-)

Maybe the real answer to my question would be; if you were rebuilding a
bicycle hub for your own use, you have both retainers from the old bearing
and also have a plentiful supply of bearing balls ready to hand - would you
re-use the retainers or fill the ball races?


I believe that I would just replace the bearing with the same type of
bearing as was originally fitted :-)
--
Cheers,

John B.

On Sat, 20 Apr 2013 01:29:22 +0100, Phil W Lee
wrote:

"Ian Field" considered Fri, 19 Apr
2013 14:43:52 +0100 the perfect time to write:



"J.B.Slocomb" wrote in message
. ..
On Mon, 15 Apr 2013 16:29:15 +0100, "Ian Field"
wrote:



"J.B.Slocomb" wrote in message
m...
On Mon, 15 Apr 2013 12:53:37 +1000, James
wrote:

On 13/04/13 08:13, AMuzi wrote:
On 4/12/2013 3:49 PM, Ian Field wrote:
Facing the impending need to replace the back wheel, I
sorted through the 'spares' laying about (all 2 of them) -
one had a good rim (so far so good) both had loose spindles.

Both wheels use caged ball bearings and out of the 2 wheels,
there was only 1 good bearing cage - but between the 2
wheels, there was enough balls to fill one of the grooves
with balls and just a small clearance gap - just like they
did in the old days.

What I was wondering, is there some special reason to use
less ball-bearings with a cage to keep them equal distance
apart - such as the cage is cheaper than a full complement,
or they use lower grade metal, so the ball bearings cant be
allowed to be in contact with the one next to it?

Anyone know the answer?

Retainers save assembly time which is more expensive than standard
grade
bearings. Fewer balls merely add to the designer's savings. Full count
retainers can be of equal quality to regular loose Grade 25 bearings.
Retainers as you describe are usually of poor quality besides being
short count.

Without a retainer, how do the balls stay evenly spaced around the
cup/cone?

I don't think they do. I think they bunch up toward the top, leaving a
gap at the bottom, and because they touch and effectively counter
rotate, there is additional wear and friction between the balls.

Even if the retainer is poor quality, while it lasts it at least
attempts to maintain equal spacing between the balls.

But, if the balls jam together wouldn't they also jam against the
retainer sides?

I assume cartridge bearings have a better quality retainer, or at least
if properly sealed the retainer lasts longer.

Some "cartridge bearings" don't have any retainer...

All the retainers I've seen were very cheaply made and had nasty burrs
that
were tempered along with the component, the cartridge bearings usually
have
a pair of matching shells that clamp together, the only friction is
between
the balls and the smooth recesses pressed into the shells.

If "all the retainers I've seen were very cheaply made" it rather
implies that the retainers are not an important part of the bearing,
doesn't it? After all a bearing that is intended to hold the wheel on
an auto, for example, and that lasts for, say 200,000 Km, and is still
serviceable, and hasn't been greased since it was originally
installed, is likely of at least reasonable quality :-)

Maybe the real answer to my question would be; if you were rebuilding a
bicycle hub for your own use, you have both retainers from the old bearing
and also have a plentiful supply of bearing balls ready to hand - would you
re-use the retainers or fill the ball races?

I'd ditch the retainers, and fill the races with good quality balls.
But then I'm not paying minimum wage to some school-leaver to throw
the bike together.
I think the simple answer is that you can get the best result by using
loose balls, but a reasonable result, particularly using unskilled or
semi-skilled workers, with retainers. Retainers make it more
difficult to foul things up.

I suspect that the difference between retainers and bare balls would
be extremely difficult to measure, at least on a machine that is
bowered by a less than 5 H.P. engine at, what is in the bearing world,
extremely low RPM :-)
--
Cheers,

John B.

On Apr 20, 1:54*am, Phil W Lee wrote:
thirty-six considered Fri, 19 Apr 2013
03:12:00 -0700 (PDT) the perfect time to write:









On Apr 19, 4:07*am, Frank Krygowski wrote:
On Apr 18, 8:11*pm, James wrote:

On 19/04/13 08:38, Phil W Lee wrote:

*considered Thu, 18 Apr 2013 08:11:06
+1000 the perfect time to write:
The quote is not clear because it does not define what the increase is
with respect to. *I have read other papers that say cageless bearings
run hotter than caged bearings - thus more friction losses in the
cageless variety.

Unless you can explain how adding multiple points of sliding contact
can reduce friction over a design with only rolling contact, that
falls well short of sensible.

What is a design with only rolling contact? *If you mean a cage less
rolling bearing (ball or roller), then please explain how sliding
contact is avoided when there is no cage to keep the rolling elements
from touching?

Please also explain to me, as I've obviously lost me bearings, why a
google search yields results such as;

"Ball Cage Effect
The early forms of ball bearings were full-ball types without ball
cages. Friction between balls caused loud
noise, made high-speed rotation impossible and shortened the service
life. Twenty years later, a Caged Ball
design was developed for ball bearings. The new design enabled
high-speed rotation at a low noise level,
and extended the service life despite the reduced number of balls used.
It marked a major development in
the history of ball bearings.
Similarly, the quality of needle bearings was significantly improved by
the caged needle structure.
With cage-less, full-ball types of ball bearings, balls make metallic
contact with one another and
produce loud noise. In addition, they rotate in opposite directions,
causing the sliding contact between two
adjacent balls to occur at a speed twice the ball-spinning rate. It
results in severe wear and shortens the
service life.
In addition, without a cage, balls make point contact to increase
bearing stress, thus facilitating
breakage of the oil film. In contrast, each caged ball contacts the cage
over a wide area. Therefore, the oil
film does not break, the noise level is low and balls can rotate at a
high speed, resulting in a long
service life."

(google "site:tech.thk.com Caged Ball SHS")

Looks to me like they're advertising their design feature.

I left all my bearing catalogs behind when I retired, but I know for
sure that a bearing's load capacity is increased when the number of
balls increases. For ordinary industrial ball bearings, the type with
the cage is called a Conrad bearing; it's the basic type. *The type
that crams an extra ball or two into the groove is called a slot-fill
bearing, or full complement bearing. *Its radial load capacity is
definitely higher, due to the higher ball count. *(Its axial load
capacity is far lower, due to the groove.)

It may be that caged ball bearings are better for high speeds, but
that has nothing to do with bicycle applications. *With the cycling
penchant for light weight, we're more concerned with getting
sufficient load capacity out of the smallest, lightest assembly. *That
calls for a full complement of bearing balls.

The SKF site is good for browsing and learning. *Seehttp://www.skf.com/group/products/bearings-units-housings/ball-bearin...
for example.

- Frank Krygowski

without the spacer the balls are forced against each other and
ovalise.

What forces them against each other?

I'm not submitting an argument for courtroom entertainment, I have not
the words. They just do.

Why would it force the balls against each other, but somehow not force
the balls against the spacer?

I've seen more bearings wrecked by a spacer breaking up inside than
all other causes put together, which doesn't say much for the lifespan
enhancing properties of the cage.


I've seen more monkeys. Good cages installed correctly with good
balls last.









* * * *The bearing has a shorter lifespan whatever speed it turns
unless there is a constant oil feed, in which case it might not matter
with a low speed application and a saving can be made on bearing size,
which is useful when loads are 10 tonnes and bearing speed is below
10rev/min.

When bicycles were oiled before riding the use of unspaced balls was
acceptable but when laziness and Brandtian thoughts of putting money
into the pockets of the oil companies became more prevelant, a belief
was born that bicycle bearings could work without routine attention to
lubrication.

I questioned the notion that bicycles don't need oiling in 1983. *It
seemed that bicycle shops were encouraging laziness and with further
experience I found that bearings generally failed within two years,
unless the bicycle was annually serviced. *Clever eh?

When a bearing heavily loaded and run at low speed as on a bicycle it
becomes even more important that when grease is used it is
sufficiently fluid at the operating temperature that the balls are
continually wetted. *There is also some pumping of a correctly
specified grease which pushes the debris away from the balls and track
and brings in clean lubricant. *I have found calcium grease with extra
oil to be most suitable for the wheel and crank bearings. * MoS2 can
also be used to help the load capacity and extend bearing life almost
indefinitely as long as routine checks are made that the bearing is
still wet and there is no stiffness or grittiness when examination is
made with a stethescope.

The only way MoS2 can extend the life of the bearing is by limiting
the effects of wear.
It reduces friction - but if that allows the balls to skid instead of
roll, it'll make things worse, not better.

Have you been drinking again?

It's main benefit is in sliding contacts, where friction reduction has
the greatest benefit.
Once there's any sliding going on in a roller bearing, you are already
into damage limitation.

There is always sliding, unless the bearing is getting torn apart,
which is what happens when your banana munching mates run bearings
without a lubricant.

I think you are having trouble understanding the meaning of "high
speed" in relation to bearings.

You also beleive in Daddy Christmas and the tooth fairy.

Cages can have their uses in bearings that are sufficiently high speed
that bunching of the balls would have severe effects on the balance.
That is certainly not the case in anything on a bicycle.

I've seen the effect of running a bicycle wheel bearing in a standard
"cycle" grease with loose balls. At the upper riding speeds the
grease cavitates and the balls roll on a single axis, without spin.
The tracks as well as the balls are not adequately lubricated. The
balls will wear taking them out of sphericity and the tracks will fail
from fatigue. If left long enough without adequate lubrication, ome
balls may crack in two and get caught up with the cage so churning
that up.

The cage stops the cavitation of grease and the balls, as long as they
are spherical, will spin so providing adequate lubrication above 12mph
(chosen from the air).

My regular speeds were up to around 40mph and less frequently 68mph.
I trashed wheel bearings regularly for a few years, more than my mates
probably because I liked those long downhill runs. I gave up on their
(and shop) recommendations as my demands were obviously greater than
the regular racer. I sought out speed. A ball only fill with a
slack grease did not withstand my use, the wheel bearings had to be
either regularly oiled, when ball only, or caged with a slack
grease.

"Phil W Lee" wrote in message
...
"Ian Field" considered Fri, 19 Apr
2013 14:43:52 +0100 the perfect time to write:



"J.B.Slocomb" wrote in message
. ..
On Mon, 15 Apr 2013 16:29:15 +0100, "Ian Field"
wrote:



"J.B.Slocomb" wrote in message
m...
On Mon, 15 Apr 2013 12:53:37 +1000, James
wrote:

On 13/04/13 08:13, AMuzi wrote:
On 4/12/2013 3:49 PM, Ian Field wrote:
Facing the impending need to replace the back wheel, I
sorted through the 'spares' laying about (all 2 of them) -
one had a good rim (so far so good) both had loose spindles.

Both wheels use caged ball bearings and out of the 2 wheels,
there was only 1 good bearing cage - but between the 2
wheels, there was enough balls to fill one of the grooves
with balls and just a small clearance gap - just like they
did in the old days.

What I was wondering, is there some special reason to use
less ball-bearings with a cage to keep them equal distance
apart - such as the cage is cheaper than a full complement,
or they use lower grade metal, so the ball bearings cant be
allowed to be in contact with the one next to it?

Anyone know the answer?

Retainers save assembly time which is more expensive than standard
grade
bearings. Fewer balls merely add to the designer's savings. Full
count
retainers can be of equal quality to regular loose Grade 25
bearings.
Retainers as you describe are usually of poor quality besides being
short count.

Without a retainer, how do the balls stay evenly spaced around the
cup/cone?

I don't think they do. I think they bunch up toward the top, leaving
a
gap at the bottom, and because they touch and effectively counter
rotate, there is additional wear and friction between the balls.

Even if the retainer is poor quality, while it lasts it at least
attempts to maintain equal spacing between the balls.

But, if the balls jam together wouldn't they also jam against the
retainer sides?

I assume cartridge bearings have a better quality retainer, or at
least
if properly sealed the retainer lasts longer.

Some "cartridge bearings" don't have any retainer...

All the retainers I've seen were very cheaply made and had nasty burrs
that
were tempered along with the component, the cartridge bearings usually
have
a pair of matching shells that clamp together, the only friction is
between
the balls and the smooth recesses pressed into the shells.

If "all the retainers I've seen were very cheaply made" it rather
implies that the retainers are not an important part of the bearing,
doesn't it? After all a bearing that is intended to hold the wheel on
an auto, for example, and that lasts for, say 200,000 Km, and is still
serviceable, and hasn't been greased since it was originally
installed, is likely of at least reasonable quality :-)

Maybe the real answer to my question would be; if you were rebuilding a
bicycle hub for your own use, you have both retainers from the old bearing
and also have a plentiful supply of bearing balls ready to hand - would
you
re-use the retainers or fill the ball races?

I'd ditch the retainers, and fill the races with good quality balls.
But then I'm not paying minimum wage to some school-leaver to throw
the bike together.
I think the simple answer is that you can get the best result by using
loose balls, but a reasonable result, particularly using unskilled or
semi-skilled workers, with retainers. Retainers make it more
difficult to foul things up.

Not judging by the number of bearings I've encountered with scrunched
retainers and balls loose in the housing!

On Saturday, April 20, 2013 11:12:55 AM UTC-4, thirty-six wrote:
On Apr 20, 1:54*am, Phil W Lee wrote:

Cages can have their uses in bearings that are sufficiently high speed

that bunching of the balls would have severe effects on the balance.

That is certainly not the case in anything on a bicycle.



I've seen the effect of running a bicycle wheel bearing in a standard

"cycle" grease with loose balls. At the upper riding speeds the

grease cavitates and the balls roll on a single axis, without spin.

The tracks as well as the balls are not adequately lubricated. The

balls will wear taking them out of sphericity and the tracks will fail

from fatigue. If left long enough without adequate lubrication, ome

balls may crack in two and get caught up with the cage so churning

that up.

I'm a little curious how you observed the grease "cavitating" while riding at high speeds. And if you did observe cavitation (did you mean air bubbles in the grease?) why you think it would have a deleterious effect on the lubrication.

The cage stops the cavitation of grease and the balls...

And how or why the cage would stop the air bubbles in the grease.

My regular speeds were up to around 40mph and less frequently 68mph.

Even 68 mph works out to only about 850 rpm for a typical bike wheel. In the world of bearing design, that definitely qualifies as low speed. It's below the idling speed of a lot of engines, below what auto, motorcycle and trailer wheels do for many tens of thousands of maintenance-free miles.

I trashed wheel bearings regularly for a few years, more than my mates

probably because I liked those long downhill runs. I gave up on their

(and shop) recommendations as my demands were obviously greater than

the regular racer. I sought out speed. A ball only fill with a

slack grease did not withstand my use, the wheel bearings had to be

either regularly oiled, when ball only, or caged with a slack

grease.

Well, I'm glad you found a regimen that works for you. I've tried oiling bearings (and still do a bit of it when I'm too lazy to re-pack a hub) but I eventually decided I didn't care for the seemingly inevitable seepage and resulting dirt accumulation. YMMV.

- Frank Krygowski

On 4/20/2013 10:12 AM, thirty-six wrote:
On Apr 20, 1:54 am, Phil W Lee wrote:
thirty-six considered Fri, 19 Apr 2013
03:12:00 -0700 (PDT) the perfect time to write:









On Apr 19, 4:07 am, Frank Krygowski wrote:
On Apr 18, 8:11 pm, James wrote:

On 19/04/13 08:38, Phil W Lee wrote:

considered Thu, 18 Apr 2013 08:11:06
+1000 the perfect time to write:
The quote is not clear because it does not define what the increase is
with respect to. I have read other papers that say cageless bearings
run hotter than caged bearings - thus more friction losses in the
cageless variety.

Unless you can explain how adding multiple points of sliding contact
can reduce friction over a design with only rolling contact, that
falls well short of sensible.

What is a design with only rolling contact? If you mean a cage less
rolling bearing (ball or roller), then please explain how sliding
contact is avoided when there is no cage to keep the rolling elements
from touching?

Please also explain to me, as I've obviously lost me bearings, why a
google search yields results such as;

"Ball Cage Effect
The early forms of ball bearings were full-ball types without ball
cages. Friction between balls caused loud
noise, made high-speed rotation impossible and shortened the service
life. Twenty years later, a Caged Ball
design was developed for ball bearings. The new design enabled
high-speed rotation at a low noise level,
and extended the service life despite the reduced number of balls used.
It marked a major development in
the history of ball bearings.
Similarly, the quality of needle bearings was significantly improved by
the caged needle structure.
With cage-less, full-ball types of ball bearings, balls make metallic
contact with one another and
produce loud noise. In addition, they rotate in opposite directions,
causing the sliding contact between two
adjacent balls to occur at a speed twice the ball-spinning rate. It
results in severe wear and shortens the
service life.
In addition, without a cage, balls make point contact to increase
bearing stress, thus facilitating
breakage of the oil film. In contrast, each caged ball contacts the cage
over a wide area. Therefore, the oil
film does not break, the noise level is low and balls can rotate at a
high speed, resulting in a long
service life."

(google "site:tech.thk.com Caged Ball SHS")

Looks to me like they're advertising their design feature.

I left all my bearing catalogs behind when I retired, but I know for
sure that a bearing's load capacity is increased when the number of
balls increases. For ordinary industrial ball bearings, the type with
the cage is called a Conrad bearing; it's the basic type. The type
that crams an extra ball or two into the groove is called a slot-fill
bearing, or full complement bearing. Its radial load capacity is
definitely higher, due to the higher ball count. (Its axial load
capacity is far lower, due to the groove.)

It may be that caged ball bearings are better for high speeds, but
that has nothing to do with bicycle applications. With the cycling
penchant for light weight, we're more concerned with getting
sufficient load capacity out of the smallest, lightest assembly. That
calls for a full complement of bearing balls.

The SKF site is good for browsing and learning. Seehttp://www.skf.com/group/products/bearings-units-housings/ball-bearin...
for example.

- Frank Krygowski

without the spacer the balls are forced against each other and
ovalise.

What forces them against each other?

I'm not submitting an argument for courtroom entertainment, I have not
the words. They just do.

Why would it force the balls against each other, but somehow not force
the balls against the spacer?

I've seen more bearings wrecked by a spacer breaking up inside than
all other causes put together, which doesn't say much for the lifespan
enhancing properties of the cage.


I've seen more monkeys. Good cages installed correctly with good
balls last.









The bearing has a shorter lifespan whatever speed it turns
unless there is a constant oil feed, in which case it might not matter
with a low speed application and a saving can be made on bearing size,
which is useful when loads are 10 tonnes and bearing speed is below
10rev/min.

When bicycles were oiled before riding the use of unspaced balls was
acceptable but when laziness and Brandtian thoughts of putting money
into the pockets of the oil companies became more prevelant, a belief
was born that bicycle bearings could work without routine attention to
lubrication.

I questioned the notion that bicycles don't need oiling in 1983. It
seemed that bicycle shops were encouraging laziness and with further
experience I found that bearings generally failed within two years,
unless the bicycle was annually serviced. Clever eh?

When a bearing heavily loaded and run at low speed as on a bicycle it
becomes even more important that when grease is used it is
sufficiently fluid at the operating temperature that the balls are
continually wetted. There is also some pumping of a correctly
specified grease which pushes the debris away from the balls and track
and brings in clean lubricant. I have found calcium grease with extra
oil to be most suitable for the wheel and crank bearings. MoS2 can
also be used to help the load capacity and extend bearing life almost
indefinitely as long as routine checks are made that the bearing is
still wet and there is no stiffness or grittiness when examination is
made with a stethescope.

The only way MoS2 can extend the life of the bearing is by limiting
the effects of wear.
It reduces friction - but if that allows the balls to skid instead of
roll, it'll make things worse, not better.

Have you been drinking again?

It's main benefit is in sliding contacts, where friction reduction has
the greatest benefit.
Once there's any sliding going on in a roller bearing, you are already
into damage limitation.

There is always sliding, unless the bearing is getting torn apart,
which is what happens when your banana munching mates run bearings
without a lubricant.

I think you are having trouble understanding the meaning of "high
speed" in relation to bearings.

You also beleive in Daddy Christmas and the tooth fairy.

Cages can have their uses in bearings that are sufficiently high speed
that bunching of the balls would have severe effects on the balance.
That is certainly not the case in anything on a bicycle.

I've seen the effect of running a bicycle wheel bearing in a standard
"cycle" grease with loose balls. At the upper riding speeds the
grease cavitates and the balls roll on a single axis, without spin.
The tracks as well as the balls are not adequately lubricated. The
balls will wear taking them out of sphericity and the tracks will fail
from fatigue. If left long enough without adequate lubrication, ome
balls may crack in two and get caught up with the cage so churning
that up.

The cage stops the cavitation of grease and the balls, as long as they
are spherical, will spin so providing adequate lubrication above 12mph
(chosen from the air).

My regular speeds were up to around 40mph and less frequently 68mph.
I trashed wheel bearings regularly for a few years, more than my mates
probably because I liked those long downhill runs. I gave up on their
(and shop) recommendations as my demands were obviously greater than
the regular racer. I sought out speed. A ball only fill with a
slack grease did not withstand my use, the wheel bearings had to be
either regularly oiled, when ball only, or caged with a slack
grease.




A well designed retainer (such as Campagnolo's #2101 whose
patents have expired now; analogs available cheaply from
Sugino,Tange etc) holds a full count of balls and performs
as well as loose bearings with quicker assembly. No downside
at all.

Many inexpensive designs are just barely functional. We need
to distinguish between significant factors (number of load
points, bearing quality, cup and cone material,
concentricity, hardness and finish etc) and minor factors
such as whether a retainer is supplied in the set.

Confounding all that, Murphy's Law shows us that your
average guy installs retainers backwards about half the
time, a problem with no obvious solution.

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971

"AMuzi" wrote in message
...
On 4/20/2013 10:12 AM, thirty-six wrote:
On Apr 20, 1:54 am, Phil W Lee wrote:
thirty-six considered Fri, 19 Apr 2013
03:12:00 -0700 (PDT) the perfect time to write:









On Apr 19, 4:07 am, Frank Krygowski wrote:
On Apr 18, 8:11 pm, James wrote:

On 19/04/13 08:38, Phil W Lee wrote:

considered Thu, 18 Apr 2013
08:11:06
+1000 the perfect time to write:
The quote is not clear because it does not define what the increase
is
with respect to. I have read other papers that say cageless
bearings
run hotter than caged bearings - thus more friction losses in the
cageless variety.

Unless you can explain how adding multiple points of sliding contact
can reduce friction over a design with only rolling contact, that
falls well short of sensible.

What is a design with only rolling contact? If you mean a cage less
rolling bearing (ball or roller), then please explain how sliding
contact is avoided when there is no cage to keep the rolling elements
from touching?

Please also explain to me, as I've obviously lost me bearings, why a
google search yields results such as;

"Ball Cage Effect
The early forms of ball bearings were full-ball types without ball
cages. Friction between balls caused loud
noise, made high-speed rotation impossible and shortened the service
life. Twenty years later, a Caged Ball
design was developed for ball bearings. The new design enabled
high-speed rotation at a low noise level,
and extended the service life despite the reduced number of balls
used.
It marked a major development in
the history of ball bearings.
Similarly, the quality of needle bearings was significantly improved
by
the caged needle structure.
With cage-less, full-ball types of ball bearings, balls make metallic
contact with one another and
produce loud noise. In addition, they rotate in opposite directions,
causing the sliding contact between two
adjacent balls to occur at a speed twice the ball-spinning rate. It
results in severe wear and shortens the
service life.
In addition, without a cage, balls make point contact to increase
bearing stress, thus facilitating
breakage of the oil film. In contrast, each caged ball contacts the
cage
over a wide area. Therefore, the oil
film does not break, the noise level is low and balls can rotate at a
high speed, resulting in a long
service life."

(google "site:tech.thk.com Caged Ball SHS")

Looks to me like they're advertising their design feature.

I left all my bearing catalogs behind when I retired, but I know for
sure that a bearing's load capacity is increased when the number of
balls increases. For ordinary industrial ball bearings, the type with
the cage is called a Conrad bearing; it's the basic type. The type
that crams an extra ball or two into the groove is called a slot-fill
bearing, or full complement bearing. Its radial load capacity is
definitely higher, due to the higher ball count. (Its axial load
capacity is far lower, due to the groove.)

It may be that caged ball bearings are better for high speeds, but
that has nothing to do with bicycle applications. With the cycling
penchant for light weight, we're more concerned with getting
sufficient load capacity out of the smallest, lightest assembly. That
calls for a full complement of bearing balls.

The SKF site is good for browsing and learning.
Seehttp://www.skf.com/group/products/bearings-units-housings/ball-bearin...
for example.

- Frank Krygowski

without the spacer the balls are forced against each other and
ovalise.

What forces them against each other?

I'm not submitting an argument for courtroom entertainment, I have not
the words. They just do.

Why would it force the balls against each other, but somehow not force
the balls against the spacer?

I've seen more bearings wrecked by a spacer breaking up inside than
all other causes put together, which doesn't say much for the lifespan
enhancing properties of the cage.


I've seen more monkeys. Good cages installed correctly with good
balls last.









The bearing has a shorter lifespan whatever speed it turns
unless there is a constant oil feed, in which case it might not matter
with a low speed application and a saving can be made on bearing size,
which is useful when loads are 10 tonnes and bearing speed is below
10rev/min.

When bicycles were oiled before riding the use of unspaced balls was
acceptable but when laziness and Brandtian thoughts of putting money
into the pockets of the oil companies became more prevelant, a belief
was born that bicycle bearings could work without routine attention to
lubrication.

I questioned the notion that bicycles don't need oiling in 1983. It
seemed that bicycle shops were encouraging laziness and with further
experience I found that bearings generally failed within two years,
unless the bicycle was annually serviced. Clever eh?

When a bearing heavily loaded and run at low speed as on a bicycle it
becomes even more important that when grease is used it is
sufficiently fluid at the operating temperature that the balls are
continually wetted. There is also some pumping of a correctly
specified grease which pushes the debris away from the balls and track
and brings in clean lubricant. I have found calcium grease with extra
oil to be most suitable for the wheel and crank bearings. MoS2 can
also be used to help the load capacity and extend bearing life almost
indefinitely as long as routine checks are made that the bearing is
still wet and there is no stiffness or grittiness when examination is
made with a stethescope.

The only way MoS2 can extend the life of the bearing is by limiting
the effects of wear.
It reduces friction - but if that allows the balls to skid instead of
roll, it'll make things worse, not better.

Have you been drinking again?

It's main benefit is in sliding contacts, where friction reduction has
the greatest benefit.
Once there's any sliding going on in a roller bearing, you are already
into damage limitation.

There is always sliding, unless the bearing is getting torn apart,
which is what happens when your banana munching mates run bearings
without a lubricant.

I think you are having trouble understanding the meaning of "high
speed" in relation to bearings.

You also beleive in Daddy Christmas and the tooth fairy.

Cages can have their uses in bearings that are sufficiently high speed
that bunching of the balls would have severe effects on the balance.
That is certainly not the case in anything on a bicycle.

I've seen the effect of running a bicycle wheel bearing in a standard
"cycle" grease with loose balls. At the upper riding speeds the
grease cavitates and the balls roll on a single axis, without spin.
The tracks as well as the balls are not adequately lubricated. The
balls will wear taking them out of sphericity and the tracks will fail
from fatigue. If left long enough without adequate lubrication, ome
balls may crack in two and get caught up with the cage so churning
that up.

The cage stops the cavitation of grease and the balls, as long as they
are spherical, will spin so providing adequate lubrication above 12mph
(chosen from the air).

My regular speeds were up to around 40mph and less frequently 68mph.
I trashed wheel bearings regularly for a few years, more than my mates
probably because I liked those long downhill runs. I gave up on their
(and shop) recommendations as my demands were obviously greater than
the regular racer. I sought out speed. A ball only fill with a
slack grease did not withstand my use, the wheel bearings had to be
either regularly oiled, when ball only, or caged with a slack
grease.




A well designed retainer (such as Campagnolo's #2101 whose patents have
expired now; analogs available cheaply from Sugino,Tange etc) holds a full
count of balls and performs as well as loose bearings with quicker
assembly. No downside at all.

Many inexpensive designs are just barely functional. We need to
distinguish between significant factors (number of load points, bearing
quality, cup and cone material, concentricity, hardness and finish etc)
and minor factors such as whether a retainer is supplied in the set.

Confounding all that, Murphy's Law shows us that your average guy installs
retainers backwards about half the time, a problem with no obvious
solution.

Wouldn't someone spot something so obviously wrong when they try to adjust
the bearing for free rolling without play?!

On Thu, 18 Apr 2013 15:52:36 -0700, Dan O wrote:

Well, if the cage itself is ~static relative to the balls' rotation,
maybe it's less sliding force overall than two rolling balls rubbing
against each other (?)

That said, I prefer the idea of loose balls.

Me too. I can't stand those lycra shorts. The movement in an enclosed
space causes much more friction.
--
davethedave

"davethedave" wrote in message
...
On Thu, 18 Apr 2013 15:52:36 -0700, Dan O wrote:

Well, if the cage itself is ~static relative to the balls' rotation,
maybe it's less sliding force overall than two rolling balls rubbing
against each other (?)

That said, I prefer the idea of loose balls.

Me too. I can't stand those lycra shorts. The movement in an enclosed
space causes much more friction.

To quote Bart Simpson: "there's nothing like the roomy comfort of an
unfurnished basement".

On Apr 20, 4:36*pm, wrote:
On Saturday, April 20, 2013 11:12:55 AM UTC-4, thirty-six wrote:
On Apr 20, 1:54*am, Phil W Lee wrote:

Cages can have their uses in bearings that are sufficiently high speed

that bunching of the balls would have severe effects on the balance.

That is certainly not the case in anything on a bicycle.

I've seen the effect of running a bicycle wheel bearing in a standard

"cycle" grease with loose balls. *At the upper riding speeds the

grease cavitates and the balls roll on a single axis, without spin.

The tracks as well as the balls are not adequately lubricated. * The

balls will wear taking them out of sphericity and the tracks will fail

from fatigue. *If left long enough without adequate lubrication, ome

balls may crack in two and get caught up with the cage so churning

that up.

I'm a little curious how you observed the grease "cavitating" while riding at high speeds.


I did the sensible option and recreated the rotating wheel with the
dustcap pulled from the left side of the rear wheel, by putting the
bike upside down and turning the cranks. Cor Frank, your training/
conditioning has worked well, hasn't it? Don't you remember running
on the beach naked, in and out of the sea, you know when life was just
great?

*And if you did observe cavitation (did you mean air bubbles in the grease?) why you think it would have a deleterious effect on the lubrication.

I don't need to think it, it does. I've ridden the bearings with that
setup of lubrication and none lasted 18 months despite fancy teflon-
loaded bicycle specific grease.

The cage stops the cavitation of grease and the balls...

And how or why the cage would stop the air bubbles in the grease.

It just does, no-one persuades it either way, it has no auditory or
mental capacity. That's just the way it is. Try persuading it with a
cup of chamomile tea if you like. I wasn't too bothered, so left it
be.


My regular speeds were up to around 40mph and less frequently 68mph.

Even 68 mph works out to only about 850 rpm for a typical bike wheel. *In the world of bearing design, that definitely qualifies as low speed. *It's below the idling speed of a lot of engines, below what auto, motorcycle and trailer wheels do for many tens of thousands of maintenance-free miles.

Yes, it is low-speed for a caged bearing but goes beyond the limits of
an uncaged bearing due to cavitation of grease.


I trashed wheel bearings regularly for a few years, more than my mates

probably because I liked those long downhill runs. *I gave up on their

(and shop) recommendations as my demands were obviously greater than

the regular racer. *I sought out speed. * A ball only fill with a

slack grease did not withstand my use, the wheel bearings had to be

either regularly oiled, when ball only, or caged with a slack

grease.

Well, I'm glad you found a regimen that works for you. *I've tried oiling bearings (and still do a bit of it when I'm too lazy to re-pack a hub) but I eventually decided I didn't care for the seemingly inevitable seepage and resulting dirt accumulation. *YMMV.

I've had no trouble with wheel and crank bracket using calcium grease,
initially slackened with 3in1 cycle-oil and topping it up every 6
months with a few drops of, latterly, Weldtite cycle oil.


You still must cling to your beliefs eh?