MTB cone type wheel bearings.

On Tue, 23 Apr 2013 08:25:39 +1000, James
wrote:

On 23/04/13 02:45, Phil W Lee wrote:
considered Mon, 22 Apr 2013 08:27:11
+1000 the perfect time to write:

On 19/04/13 13:50, David Scheidt wrote:
Frank wrote:
:On Apr 18, 8:11 pm, 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.)

Conrad and slot fill bearings are relevant to bearings designed to
carry a purely radial load. Remember, of course, that a cup and cone
bicycle bearing is an angular contact bearing, which can carry radial and
axial loads in different proportion by varying the angles of the races.
Importantly, they can be made as a full complement bearing without
needing the slot for assembly, since they come apart axially. The Conrad
bearing solved James's objection that without a cage, the balls will
move, which does lead to bearing failure. But with a full complement of
balls, you don't need a cage to maintain spacing, since there's no extra
space to dispalce into. The cage is really just for easy of assembly
(and maybe stocking spares). It's often used to reduce the number of
balls in the bearing, but it needn't be.



My objection was not only that the balls can move and not be evenly
spaced, but that they press against one another without a cage, and the
relative motion between the rubbing surfaces is in opposing directions.

But they won't press against each other any more than they would press
against a cage, and certainly not as continuously.

Where is your evidence?

The pressure and speed of relative motion is greater than that seen when
there is a cage to keep the balls separated.

The pressure is (at most) the same as for a cage, and is between two
hardened, curved, surfaces, and only intermittently.

Again, your evidence?

It has been noted that full compliment bearings run hotter, and need
better lubrication flow (than a caged bearing) to maintain a lubrication
film between the balls. I.e. there is more friction and wear. The type
of lubrication required for longevity is not so easy to achieve in a
bicycle hub or BB.

No more difficult than in a wheel bearing or suspension pivot of a
car, and much less heavily loaded.

Car wheel bearings (tapered roller) have a cage - at least all those
that I've worked on have. And in fact wheel bearings on car trailers
are notorious for self destruction because the lubrication is
insufficient, they tend to not be used often, and the hub tends to let
moisture in - much like bicycle hubs.

I've yet to hear of any bicycle application where heat is a problem in
any (properly maintained) bearing.

Heat is indicative of friction. The research papers and other sources
I've read say that full compliment bearings get hotter, therefore there
is more friction.

Friction usually leads to wear, therefore I conclude they wear out
faster too.

On the other hand the more balls the more the bearing will support,
attested by research papers also. So which is better, the pillar or
the post :-)
--
Cheers,

John B.

ahhhh I found a tub of extinct Castroll SYNTH Boat trailer bearing marine grease in GARAGE 2. EYEYYEYHAHHHAHAHAHAHAH...max !

if you hub listen with a stethescope or pipe to forehead with ear plugs in, you will hear the balls running into each other.

http://www.globalspec.com/learnmore/...ings_all_types

On 23/04/13 09:38, J.B.Slocomb wrote:
On Tue, 23 Apr 2013 08:25:39 +1000,
wrote:

On 23/04/13 02:45, Phil W Lee wrote:
considered Mon, 22 Apr 2013 08:27:11
+1000 the perfect time to write:

On 19/04/13 13:50, David Scheidt wrote:
Frank wrote:
:On Apr 18, 8:11 pm, 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.)

Conrad and slot fill bearings are relevant to bearings designed to
carry a purely radial load. Remember, of course, that a cup and cone
bicycle bearing is an angular contact bearing, which can carry radial and
axial loads in different proportion by varying the angles of the races.
Importantly, they can be made as a full complement bearing without
needing the slot for assembly, since they come apart axially. The Conrad
bearing solved James's objection that without a cage, the balls will
move, which does lead to bearing failure. But with a full complement of
balls, you don't need a cage to maintain spacing, since there's no extra
space to dispalce into. The cage is really just for easy of assembly
(and maybe stocking spares). It's often used to reduce the number of
balls in the bearing, but it needn't be.



My objection was not only that the balls can move and not be evenly
spaced, but that they press against one another without a cage, and the
relative motion between the rubbing surfaces is in opposing directions.

But they won't press against each other any more than they would press
against a cage, and certainly not as continuously.

Where is your evidence?

The pressure and speed of relative motion is greater than that seen when
there is a cage to keep the balls separated.

The pressure is (at most) the same as for a cage, and is between two
hardened, curved, surfaces, and only intermittently.

Again, your evidence?

It has been noted that full compliment bearings run hotter, and need
better lubrication flow (than a caged bearing) to maintain a lubrication
film between the balls. I.e. there is more friction and wear. The type
of lubrication required for longevity is not so easy to achieve in a
bicycle hub or BB.

No more difficult than in a wheel bearing or suspension pivot of a
car, and much less heavily loaded.

Car wheel bearings (tapered roller) have a cage - at least all those
that I've worked on have. And in fact wheel bearings on car trailers
are notorious for self destruction because the lubrication is
insufficient, they tend to not be used often, and the hub tends to let
moisture in - much like bicycle hubs.

I've yet to hear of any bicycle application where heat is a problem in
any (properly maintained) bearing.

Heat is indicative of friction. The research papers and other sources
I've read say that full compliment bearings get hotter, therefore there
is more friction.

Friction usually leads to wear, therefore I conclude they wear out
faster too.

On the other hand the more balls the more the bearing will support,
attested by research papers also. So which is better, the pillar or
the post :-)

Yes, John, we've been over that before. The more balls support more
load, and provided the speed is kept low (gee, think why that might be),
and the lubrication adequate (which is unlikely in a bicycle hub or BB),
they are ok.

Much better though to increase the size of the housing just a smidge to
allow for larger balls and bearing surfaces and a cage. Then there is
less friction, less wear and a lubrication reservoir in the cage.

--
JS.

On 23/04/13 10:02, datakoll wrote:

if you hub listen with a stethescope or pipe to forehead with ear plugs in, you will hear the balls running into each other.

It must be painful for them.

On Monday, April 22, 2013 6:19:37 PM UTC-4, James wrote:
On 23/04/13 01:09, Ian Field wrote:



The ball to ball contact is very smooth & shiny - and hopefully well

lubricated.



In a bicycle hub or BB, not really well lubricated. I.e., not a

continuous flow of liquid lubricant.



The retainer is usually a stamped, formed and tempered bit of steel with

sharp edges and burrs.



And smooth enough where it counts, and provides a lubricant reservoir,

I'm told.



And - apparently, some Muppets put them in back to front!



Anything is possible. Thankfully cartridge bearings with seals both

sides solve the problem.

With most sealed cartridge bearings I've examined, there's far more friction from the seals than there would ever be from inter-ball contact. Nonetheless, even that seal friction is negligible in any practical sense.

I've got sealed bearings on the hubs of three bikes and on the cranks of at least two. (I'm not sure about some others.) Particularly with the hubs when new, it was obvious when spinning the axles with my fingers (wheels out of the bike) that there was a tiny bit more friction. But I was happy to accept it in return for freedom from maintenance. It's never slowed me noticeably (if at all), and I've literally gone decades with no more than a few minutes of bearing maintenance. (ISTR using a hypodermic needle to inject a bit of oil into my Phil Wood hub bearings after maybe 15 years.)

Again: Several designs work well here, with only negligible differences between their friction characteristics.

(I know - but if we accept that, what on earth would we discuss?)

- Frank Krygowski

On 23/04/13 10:32, wrote:
On Monday, April 22, 2013 6:19:37 PM UTC-4, James wrote:
On 23/04/13 01:09, Ian Field wrote:



The ball to ball contact is very smooth& shiny - and hopefully
well

lubricated.



In a bicycle hub or BB, not really well lubricated. I.e., not a

continuous flow of liquid lubricant.



The retainer is usually a stamped, formed and tempered bit of
steel with

sharp edges and burrs.



And smooth enough where it counts, and provides a lubricant
reservoir,

I'm told.



And - apparently, some Muppets put them in back to front!



Anything is possible. Thankfully cartridge bearings with seals
both

sides solve the problem.

With most sealed cartridge bearings I've examined, there's far more
friction from the seals than there would ever be from inter-ball
contact. Nonetheless, even that seal friction is negligible in any
practical sense.

Do you have any evidence?

And even so, I'd rather expend a little energy and keep good seals than
have bearings wear out fast.

I've got sealed bearings on the hubs of three bikes and on the cranks
of at least two. (I'm not sure about some others.) Particularly
with the hubs when new, it was obvious when spinning the axles with
my fingers (wheels out of the bike) that there was a tiny bit more
friction. But I was happy to accept it in return for freedom from
maintenance.

And I bet the hub manufacturer didn't specify full complement bearings
either. Why is that? Don't you think they would want the best solution
for their product? Or do you think it's a conspiracy to sell more
bearings because less balls wear out faster in your opinion - because of
the lower load rating? Are they custom bearings for their hub?

The hubs I have that take cartridge bearings are very much standard, and
have a cage, same as all the different BB's I've owned over the years
from Shimano and Campag. (Actually the Ultra Torque BB bearings from
Campag are not quite standard, but they still have a cage).

It's never slowed me noticeably (if at all), and I've
literally gone decades with no more than a few minutes of bearing
maintenance. (ISTR using a hypodermic needle to inject a bit of oil
into my Phil Wood hub bearings after maybe 15 years.)

Again: Several designs work well here, with only negligible
differences between their friction characteristics.

(I know - but if we accept that, what on earth would we discuss?)


I never said I was concerned about *me* or anyone else overcoming the
bearing friction. I contend that there is more friction in a full
complement bearing than a caged type, that causes faster wear and
premature bearing failure.

The bearing losses has been done to death, and is about 0.5 Watts or so
per cartridge bearing at reasonable bike speed, and 0.4 Watts of that is
lost in the seals on a bearing with seals each side.

Really the question is of the suitability of full compliment bearings to
bicycles. And yes they "work" for some values of "work", but from what
I've seen some folks riding, "works" has a very wide range of acceptance.

--
JS

On Apr 22, 8:56*pm, James wrote:
On 23/04/13 10:32, wrote:


With most sealed cartridge bearings I've examined, there's far more
friction from the seals than there would ever be from inter-ball
contact. *Nonetheless, even that seal friction is negligible in any
practical sense.

Do you have any evidence?

You mean that I'm remembering correctly, or not lying? No, but I'd
prefer finding out whether anyone really doubts me before I go
downstairs, pull out a wheel, remove a quick release and take some
very fine torque readings.

I'd think it would be hard to believe that an elastomer seal rubbing
agains a bearing's race would not have a _little_ more friction than a
bearing lacking such a seal.


And even so, I'd rather expend a little energy and keep good seals than
have bearings wear out fast.

Me too, as I said.



I've got sealed bearings on the hubs of three bikes and on the cranks
of at least two. *(I'm not sure about some others.) *Particularly
with the hubs when new, it was obvious when spinning the axles with
my fingers (wheels out of the bike) that there was a tiny bit more
friction. *But I was happy to accept it in return for freedom from
maintenance.

And I bet the hub manufacturer didn't specify full complement bearings
either. *Why is that? *Don't you think they would want the best solution
for their product?

OK, that's an excellent question. Let's examine it! Does a
manufacturer want a "best solution"?

Well, I suppose that ideally, they want the solution that will best
influence their bottom line. When talking about things like hub
bearings (where sculptural art is not a factor), they want something
that will maximize profits. If they're smart, they'd be thinking
about long-term profits, which are influenced by market reviews and
their effect on the manufacturer's reputation. (Cheap junk might bump
profits up for a year, and lead to buyer abandonment.)

So the manufacturer has to take customer perception into account. He
also has to take his costs into account. In the case of hubs using
cartridge bearings, it's _much_ cheaper to install standard industrial
bearings rather than source custom ones from a bearing manufacturer.
(The hub guy won't have capability of making his own bearings.)

So what should he spec? Customers - aside from some geeks - don't
care much about friction torque measurements. So advertize
"maintenance free" and get significantly more sales.

But about full complement vs. cage bearings? Well, how would a
manufacturer even advertise that? Only a few super-geeks would know
the difference, and those guys would understand that the tradeoff
would be something like a few grams - i.e. that you could get the same
capacity by going to a much cheaper bearing one size up.

What a smart manufacturer would do would be to pick a standard sealed
cartridge bearing that would be expected to last 20 years with no
maintenance and advertise it as super-robust. That's what Phil Wood
did, and it worked well. Full complement? Seal friction? Who cares?
It's bulletproof! It's "best."


I never said I was concerned about *me* or anyone else overcoming the
bearing friction. *I contend that there is more friction in a full
complement bearing than a caged type, that causes faster wear and
premature bearing failure.

I don't know what "premature bearing failure" is in a hub bearing.
The failures I've seen (with relatively inexpensive equipment) have
been almost imperceptible - a tiny rough spot on a cone or on a cup
after many, many years of service. The bearing balls get renewed when
overhauled anyway. Real failure is so rare it seems impossible to
determine if it's occurred ahead of schedule, whatever "schedule" may
be.

One place on a bike that does see bearing failure is a headset; but
that's a different, non-rotating animal, one that fails by a very
different mechanism, discussed here thoroughly in years past. But
interestingly, in that situation, a full complement of bearing balls
is thought to help.

The bearing losses has been done to death, and is about 0.5 Watts or so
per cartridge bearing at reasonable bike speed, and 0.4 Watts of that is
lost in the seals on a bearing with seals each side.

Really the question is of the suitability of full compliment bearings to
bicycles. *And yes they "work" for some values of "work", but from what
I've seen some folks riding, "works" has a very wide range of acceptance.

That's true. Still, if a rider thinks any difference in friction
between caged vs. full complement bearings will affect his riding in
any measurable or perceptible way, he's a "princess and the pea"
guy.

- Frank Krygowski

On Tue, 23 Apr 2013 10:21:29 +1000, James
wrote:

On 23/04/13 09:38, J.B.Slocomb wrote:
On Tue, 23 Apr 2013 08:25:39 +1000,
wrote:

On 23/04/13 02:45, Phil W Lee wrote:
considered Mon, 22 Apr 2013 08:27:11
+1000 the perfect time to write:

On 19/04/13 13:50, David Scheidt wrote:
Frank wrote:
:On Apr 18, 8:11 pm, 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.)

Conrad and slot fill bearings are relevant to bearings designed to
carry a purely radial load. Remember, of course, that a cup and cone
bicycle bearing is an angular contact bearing, which can carry radial and
axial loads in different proportion by varying the angles of the races.
Importantly, they can be made as a full complement bearing without
needing the slot for assembly, since they come apart axially. The Conrad
bearing solved James's objection that without a cage, the balls will
move, which does lead to bearing failure. But with a full complement of
balls, you don't need a cage to maintain spacing, since there's no extra
space to dispalce into. The cage is really just for easy of assembly
(and maybe stocking spares). It's often used to reduce the number of
balls in the bearing, but it needn't be.



My objection was not only that the balls can move and not be evenly
spaced, but that they press against one another without a cage, and the
relative motion between the rubbing surfaces is in opposing directions.

But they won't press against each other any more than they would press
against a cage, and certainly not as continuously.

Where is your evidence?

The pressure and speed of relative motion is greater than that seen when
there is a cage to keep the balls separated.

The pressure is (at most) the same as for a cage, and is between two
hardened, curved, surfaces, and only intermittently.

Again, your evidence?

It has been noted that full compliment bearings run hotter, and need
better lubrication flow (than a caged bearing) to maintain a lubrication
film between the balls. I.e. there is more friction and wear. The type
of lubrication required for longevity is not so easy to achieve in a
bicycle hub or BB.

No more difficult than in a wheel bearing or suspension pivot of a
car, and much less heavily loaded.

Car wheel bearings (tapered roller) have a cage - at least all those
that I've worked on have. And in fact wheel bearings on car trailers
are notorious for self destruction because the lubrication is
insufficient, they tend to not be used often, and the hub tends to let
moisture in - much like bicycle hubs.

I've yet to hear of any bicycle application where heat is a problem in
any (properly maintained) bearing.

Heat is indicative of friction. The research papers and other sources
I've read say that full compliment bearings get hotter, therefore there
is more friction.

Friction usually leads to wear, therefore I conclude they wear out
faster too.

On the other hand the more balls the more the bearing will support,
attested by research papers also. So which is better, the pillar or
the post :-)

Yes, John, we've been over that before. The more balls support more
load, and provided the speed is kept low (gee, think why that might be),
and the lubrication adequate (which is unlikely in a bicycle hub or BB),
they are ok.

Much better though to increase the size of the housing just a smidge to
allow for larger balls and bearing surfaces and a cage. Then there is
less friction, less wear and a lubrication reservoir in the cage.


On the other hand, I suspect that if you look into it you'll find that
no bearing on a bicycle turns at what the Bearing World considers
anything but slow speed. Didn't someone calculate that the wheel
bearings turned 600 rpm, max? The bottom bracket might hit 200 rpm and
the head bearings are probably rated in turns per hour.

As for lubrication I recently disassembled an aluminum frame bike that
I know was ten years old and had no maintenance for that period....
both the bottom bracket and head bearings still had adequate amounts
of grease and appeared, to a casual look, to still be perfectly
serviceable.

--
Cheers,

John B.

On Mon, 22 Apr 2013 22:01:22 -0700 (PDT), Frank Krygowski
wrote:

On Apr 22, 8:56*pm, James wrote:
On 23/04/13 10:32, wrote:


With most sealed cartridge bearings I've examined, there's far more
friction from the seals than there would ever be from inter-ball
contact. *Nonetheless, even that seal friction is negligible in any
practical sense.

Do you have any evidence?

You mean that I'm remembering correctly, or not lying? No, but I'd
prefer finding out whether anyone really doubts me before I go
downstairs, pull out a wheel, remove a quick release and take some
very fine torque readings.

I'd think it would be hard to believe that an elastomer seal rubbing
agains a bearing's race would not have a _little_ more friction than a
bearing lacking such a seal.

It is likely that it does have more drag than a seal less bearing but
like many things in the bicycle world there is probably so little
difference that no one can actually tell the difference.

I've recently switched wheels between bikes. One set with Shimano
loose bearing hubs and one with cartridge bearings and frankly I can't
tell the difference.

Who was it said, "A tempest in a tea pot"?


And even so, I'd rather expend a little energy and keep good seals than
have bearings wear out fast.

Me too, as I said.



I've got sealed bearings on the hubs of three bikes and on the cranks
of at least two. *(I'm not sure about some others.) *Particularly
with the hubs when new, it was obvious when spinning the axles with
my fingers (wheels out of the bike) that there was a tiny bit more
friction. *But I was happy to accept it in return for freedom from
maintenance.

And I bet the hub manufacturer didn't specify full complement bearings
either. *Why is that? *Don't you think they would want the best solution
for their product?

OK, that's an excellent question. Let's examine it! Does a
manufacturer want a "best solution"?

Well, I suppose that ideally, they want the solution that will best
influence their bottom line. When talking about things like hub
bearings (where sculptural art is not a factor), they want something
that will maximize profits. If they're smart, they'd be thinking
about long-term profits, which are influenced by market reviews and
their effect on the manufacturer's reputation. (Cheap junk might bump
profits up for a year, and lead to buyer abandonment.)

So the manufacturer has to take customer perception into account. He
also has to take his costs into account. In the case of hubs using
cartridge bearings, it's _much_ cheaper to install standard industrial
bearings rather than source custom ones from a bearing manufacturer.
(The hub guy won't have capability of making his own bearings.)

So what should he spec? Customers - aside from some geeks - don't
care much about friction torque measurements. So advertize
"maintenance free" and get significantly more sales.

But about full complement vs. cage bearings? Well, how would a
manufacturer even advertise that? Only a few super-geeks would know
the difference, and those guys would understand that the tradeoff
would be something like a few grams - i.e. that you could get the same
capacity by going to a much cheaper bearing one size up.

What a smart manufacturer would do would be to pick a standard sealed
cartridge bearing that would be expected to last 20 years with no
maintenance and advertise it as super-robust. That's what Phil Wood
did, and it worked well. Full complement? Seal friction? Who cares?
It's bulletproof! It's "best."


I never said I was concerned about *me* or anyone else overcoming the
bearing friction. *I contend that there is more friction in a full
complement bearing than a caged type, that causes faster wear and
premature bearing failure.

I don't know what "premature bearing failure" is in a hub bearing.
The failures I've seen (with relatively inexpensive equipment) have
been almost imperceptible - a tiny rough spot on a cone or on a cup
after many, many years of service. The bearing balls get renewed when
overhauled anyway. Real failure is so rare it seems impossible to
determine if it's occurred ahead of schedule, whatever "schedule" may
be.

One place on a bike that does see bearing failure is a headset; but
that's a different, non-rotating animal, one that fails by a very
different mechanism, discussed here thoroughly in years past. But
interestingly, in that situation, a full complement of bearing balls
is thought to help.

The bearing losses has been done to death, and is about 0.5 Watts or so
per cartridge bearing at reasonable bike speed, and 0.4 Watts of that is
lost in the seals on a bearing with seals each side.

Really the question is of the suitability of full compliment bearings to
bicycles. *And yes they "work" for some values of "work", but from what
I've seen some folks riding, "works" has a very wide range of acceptance.

That's true. Still, if a rider thinks any difference in friction
between caged vs. full complement bearings will affect his riding in
any measurable or perceptible way, he's a "princess and the pea"
guy.

- Frank Krygowski
--
Cheers,

John B.

On Tuesday, April 23, 2013 7:09:58 AM UTC-4, J. B. Slocomb wrote:
On Tue, 23 Apr 2013 10:21:29 +1000, James

wrote:



On 23/04/13 09:38, J.B.Slocomb wrote:

On Tue, 23 Apr 2013 08:25:39 +1000,

wrote:



On 23/04/13 02:45, Phil W Lee wrote:

considered Mon, 22 Apr 2013 08:27:11

+1000 the perfect time to write:



On 19/04/13 13:50, David Scheidt wrote:

Frank wrote:

:On Apr 18, 8:11 pm, 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.)



Conrad and slot fill bearings are relevant to bearings designed to

carry a purely radial load. Remember, of course, that a cup and cone

bicycle bearing is an angular contact bearing, which can carry radial and

axial loads in different proportion by varying the angles of the races.

Importantly, they can be made as a full complement bearing without

needing the slot for assembly, since they come apart axially. The Conrad

bearing solved James's objection that without a cage, the balls will

move, which does lead to bearing failure. But with a full complement of

balls, you don't need a cage to maintain spacing, since there's no extra

space to dispalce into. The cage is really just for easy of assembly

(and maybe stocking spares). It's often used to reduce the number of

balls in the bearing, but it needn't be.







My objection was not only that the balls can move and not be evenly

spaced, but that they press against one another without a cage, and the

relative motion between the rubbing surfaces is in opposing directions.



But they won't press against each other any more than they would press

against a cage, and certainly not as continuously.



Where is your evidence?



The pressure and speed of relative motion is greater than that seen when

there is a cage to keep the balls separated.



The pressure is (at most) the same as for a cage, and is between two

hardened, curved, surfaces, and only intermittently.



Again, your evidence?



It has been noted that full compliment bearings run hotter, and need

better lubrication flow (than a caged bearing) to maintain a lubrication

film between the balls. I.e. there is more friction and wear. The type

of lubrication required for longevity is not so easy to achieve in a

bicycle hub or BB.



No more difficult than in a wheel bearing or suspension pivot of a

car, and much less heavily loaded.



Car wheel bearings (tapered roller) have a cage - at least all those

that I've worked on have. And in fact wheel bearings on car trailers

are notorious for self destruction because the lubrication is

insufficient, they tend to not be used often, and the hub tends to let

moisture in - much like bicycle hubs.



I've yet to hear of any bicycle application where heat is a problem in

any (properly maintained) bearing.



Heat is indicative of friction. The research papers and other sources

I've read say that full compliment bearings get hotter, therefore there

is more friction.



Friction usually leads to wear, therefore I conclude they wear out

faster too.



On the other hand the more balls the more the bearing will support,

attested by research papers also. So which is better, the pillar or

the post :-)



Yes, John, we've been over that before. The more balls support more

load, and provided the speed is kept low (gee, think why that might be),

and the lubrication adequate (which is unlikely in a bicycle hub or BB),

they are ok.



Much better though to increase the size of the housing just a smidge to

allow for larger balls and bearing surfaces and a cage. Then there is

less friction, less wear and a lubrication reservoir in the cage.





On the other hand, I suspect that if you look into it you'll find that

no bearing on a bicycle turns at what the Bearing World considers

anything but slow speed. Didn't someone calculate that the wheel

bearings turned 600 rpm, max? The bottom bracket might hit 200 rpm and

the head bearings are probably rated in turns per hour.



As for lubrication I recently disassembled an aluminum frame bike that

I know was ten years old and had no maintenance for that period....

both the bottom bracket and head bearings still had adequate amounts

of grease and appeared, to a casual look, to still be perfectly

serviceable.



--

Cheers,



John B.

.........

if so, your climate saved the grease from evaporating or absolving. here in South Florida, standard soap or petro greases evap in 4-5 years leaving the hardend grease rims mentioned.