ceramic bearings

"Rick Roof" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Just installed ceramic bearings in my front wheel. The original
bearings seem much smoother. Is this just because the ceramics are
not broke in?

If there was a difference in 'smoothness' between steel and ceramic
bearings, it would be so infintesimal so as to be immesurable with real
equipment. Difference in watts power usage on the bike?? Basically zero.
Aerodynamics is many orders of magnitude more important.

The only possible positive of ceramics is that they may survive a little
longer in a hub that is contaminated with grit and water. Maybe.

But this brings up the bigger question as to why not just appropriately
maintain your hubs? An even better solution would be to get a hub that has
a grease injection port. Then, maintenance would amount to a minute per
year to squeeze some grease into the hub shell and wipe up the old stuff.

"Dave Mayer" <[email hidden]> wrote in message
news:rxhLj.168159$pM4.160323@pd7urf1no...

Quoted message said:

"Rick Roof" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Just installed ceramic bearings in my front wheel. The original
bearings seem much smoother. Is this just because the ceramics are
not broke in?

If there was a difference in 'smoothness' between steel and ceramic
bearings, it would be so infintesimal so as to be immesurable with real
equipment. Difference in watts power usage on the bike?? Basically zero.
Aerodynamics is many orders of magnitude more important.

The only possible positive of ceramics is that they may survive a little
longer in a hub that is contaminated with grit and water. Maybe.

But this brings up the bigger question as to why not just appropriately
maintain your hubs?

Agreed

Quoted message said:

An even better solution would be to get a hub that has
a grease injection port.

That is the second stupiest way to maintain a hub. The first is not to
maintain the hub at all. You have to inject a ton of grease to push out the
old dirty grease through the seal. Not very healthy for the seal. Choose a
hub that is easy (take apart and adjust afterwards) to maintain. Then you
maintain it more often. I vote for Campy hubs.

Quoted message said:

Then, maintenance would amount to a minute per
year to squeeze some grease into the hub shell and wipe up the old stuff.

Lou

"Lou Holtman" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

"Dave Mayer" <[email hidden]> wrote in message
news:rxhLj.168159$pM4.160323@pd7urf1no...

Quoted message said:

"Rick Roof" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Just installed ceramic bearings in my front wheel. The original
bearings seem much smoother. Is this just because the ceramics are
not broke in?

If there was a difference in 'smoothness' between steel and ceramic
bearings, it would be so infintesimal so as to be immesurable with real
equipment. Difference in watts power usage on the bike?? Basically
zero.
Aerodynamics is many orders of magnitude more important.

The only possible positive of ceramics is that they may survive a little
longer in a hub that is contaminated with grit and water. Maybe.

But this brings up the bigger question as to why not just appropriately
maintain your hubs?

Agreed

Quoted message said:

An even better solution would be to get a hub that has
a grease injection port.

That is the second stupiest way to maintain a hub. The first is not to
maintain the hub at all. You have to inject a ton of grease to push out
the
old dirty grease through the seal. Not very healthy for the seal. Choose a
hub that is easy (take apart and adjust afterwards) to maintain. Then you
maintain it more often. I vote for Campy hubs.

Quoted message said:

Then, maintenance would amount to a minute per
year to squeeze some grease into the hub shell and wipe up the old stuff.

Lou

I vote for sealed bearing hubs, ie, no maintenance 🙂 You just ride until
they [censored] themselves, then replace. I haven't had to replace one yet and I
have a couple of hubs that have had an absolute kaning (in the mud and
water).

I cant wait till the XT hubs on my SS die so I can replace them with some
nice DT's, then I never ever have to worry about those stupid shimano
setups, such a pain to set, especially when I have to replace *yet* another
busted freewheel assembly 🙂

Cheers Dre (talking about mtb hubs here though)

On Thu, 10 Apr 2008 05:25:43 GMT, "Dave Mayer" <[email hidden]>

may have said:

But this brings up the bigger question as to why not just appropriately
maintain your hubs? An even better solution would be to get a hub that has
a grease injection port. Then, maintenance would amount to a minute per
year to squeeze some grease into the hub shell and wipe up the old stuff.

Too much grease increases drag, at least until enough is forced back
out for the grease packs to shear and develop gaps. The amount that
would be present after pumping in enough to actually repack the
bearings would be in that range easily.

Pumping in more grease also does not remove the contaminated grease
that's already present.

Proper maintenance begins with "Clean".

--
My email address is antispammed; pull WEEDS if replying via e-mail.
Typoes are not a bug, they're a feature.
Words processed in a facility that contains nuts.

In article <[email hidden]>,

Werehatrack said:

On Thu, 10 Apr 2008 05:25:43 GMT, "Dave Mayer" <[email hidden]>

may have said:

But this brings up the bigger question as to why not just appropriately
maintain your hubs? An even better solution would be to get a hub that has
a grease injection port. Then, maintenance would amount to a minute per
year to squeeze some grease into the hub shell and wipe up the old stuff.

Too much grease increases drag, at least until enough is forced back
out for the grease packs to shear and develop gaps. The amount that
would be present after pumping in enough to actually repack the
bearings would be in that range easily.

If you can demonstrate it takes more than seconds of operation for this
to happen, I'll be impressed. The first time the bearing is operated,
the balls go through the grease like, well, a bunch of bowling balls
through soft butter. If grease needs to be displaced for the balls to
move, it happens almost immediately. The grease has virtually no ability
to resist this displacement. It's also incompressible, and has little
propensity to flow or rebound, so it doesn't return to the bearing track
except as a thin film.

Quoted message said:

Pumping in more grease also does not remove the contaminated grease
that's already present.

That's exactly what it does. Typical grease-injection hubs have a port
in the hub shell that admits grease into the axle area. the grease can
only flow from there through the bearing and then out the seals. When
clean grease is coming out of the outer seal, there is no place for
contaminated grease to be.

You don't have to believe me. Grease-ported hubs are cheap: pump and see.

--
Ryan Cousineau [email hidden] http://www.wiredcola.com/
"In other newsgroups, they killfile trolls."
"In rec.bicycles.racing, we coach them."

"Ryan Cousineau" <[email hidden]> wrote in message
news:rcousine-55D9A0.00083511042008@[74.223.185.199.nw.nuvox.net]...

Quoted message said:

In article <[email hidden]>,

Werehatrack said:

On Thu, 10 Apr 2008 05:25:43 GMT, "Dave Mayer" <[email hidden]>

may have said:

But this brings up the bigger question as to why not just appropriately
maintain your hubs? An even better solution would be to get a hub that

has

Quoted message said:

Quoted message said:

Quoted message said:

a grease injection port. Then, maintenance would amount to a minute

per

Quoted message said:

Quoted message said:

Quoted message said:

year to squeeze some grease into the hub shell and wipe up the old

stuff.

Quoted message said:

Quoted message said:

Too much grease increases drag, at least until enough is forced back
out for the grease packs to shear and develop gaps. The amount that
would be present after pumping in enough to actually repack the
bearings would be in that range easily.

If you can demonstrate it takes more than seconds of operation for this
to happen, I'll be impressed. The first time the bearing is operated,
the balls go through the grease like, well, a bunch of bowling balls
through soft butter. If grease needs to be displaced for the balls to
move, it happens almost immediately. The grease has virtually no ability
to resist this displacement. It's also incompressible, and has little
propensity to flow or rebound, so it doesn't return to the bearing track
except as a thin film.

Quoted message said:

Pumping in more grease also does not remove the contaminated grease
that's already present.

That's exactly what it does. Typical grease-injection hubs have a port
in the hub shell that admits grease into the axle area. the grease can
only flow from there through the bearing and then out the seals. When
clean grease is coming out of the outer seal, there is no place for
contaminated grease to be.

Not true. The pumped in grease seeks the easiest way out. If you see clean
grease comming out there is still contaminated grease inside in the hidden
corners.

Quoted message said:

You don't have to believe me. Grease-ported hubs are cheap: pump and see.

You don't have to believe me either.

Lou

On Fri, 11 Apr 2008 07:08:38 GMT, Ryan Cousineau <[email hidden]>

may have said:

In article <[email hidden]>,

Werehatrack said:

On Thu, 10 Apr 2008 05:25:43 GMT, "Dave Mayer" <[email hidden]>

may have said:

But this brings up the bigger question as to why not just appropriately
maintain your hubs? An even better solution would be to get a hub that has
a grease injection port. Then, maintenance would amount to a minute per
year to squeeze some grease into the hub shell and wipe up the old stuff.

Too much grease increases drag, at least until enough is forced back
out for the grease packs to shear and develop gaps. The amount that
would be present after pumping in enough to actually repack the
bearings would be in that range easily.

If you can demonstrate it takes more than seconds of operation for this
to happen, I'll be impressed.

How much are you offering to pay for the bench time? The drag is
small, but everything-weenies being what they are, it would matter to
them. (Probably nobody else, though.) Choice of grease and design of
component might have a lot to do with the clearance time.

Quoted message said:

The first time the bearing is operated,
the balls go through the grease like, well, a bunch of bowling balls
through soft butter. If grease needs to be displaced for the balls to
move, it happens almost immediately. The grease has virtually no ability
to resist this displacement. It's also incompressible, and has little
propensity to flow or rebound, so it doesn't return to the bearing track
except as a thin film.

Unless, of course, the entire cavity is filled, in which case the
incompressibility means that the balls are running in a viscous
semifluid instead of freely. This is one of the reasons why
pump-lubed hubs are not as common as they used to be, while
aftermarket ball-and-socket joints typically still get supplied with
grease fittings. (The big reason, of course, is that with modern
lubricants and components, the bearings don't require the frequency of
re-lube that old ones needed.)

I recall being told that this used to be a topic in MechE studies;
point being that one should always allow clearance room for the excess
lube to exit. Merely adding a grease fitting to a conventional hub
design is not going to meet the spec.

Quoted message said:

Quoted message said:

Pumping in more grease also does not remove the contaminated grease
that's already present.

That's exactly what it does. Typical grease-injection hubs have a port
in the hub shell that admits grease into the axle area. the grease can
only flow from there through the bearing and then out the seals. When
clean grease is coming out of the outer seal, there is no place for
contaminated grease to be.

You've never taken one apart, then? It would be educational. The
contaminated grease will be everywhere that wasn't an active loaded
surface, and the clean grease will have flowed right past it.

Quoted message said:

You don't have to believe me. Grease-ported hubs are cheap: pump and see.

I used to work on them. I'm glad that modern hubs don't have grease
fittings.

--
My email address is antispammed; pull WEEDS if replying via e-mail.
Typoes are not a bug, they're a feature.
Words processed in a facility that contains nuts.

Rick Roof said:

Just installed ceramic bearings in my front wheel. The original
bearings seem much smoother. Is this just because the ceramics are
not broke in? They just don't seem as smooth as the bearings I took
out. I ended up putting the originals back in for now. Any info
would be appreciated. Thanks.

Rick

I'm wondering if anyone is going to even remotely answer your question
instead of highjacking it for a totally irrelevant discussion. Often
the argument starts with at least a disagreement on actual advice.
Didn't even get that far! I'm curious about your question so I will
stand by (but not hold my breath).

In article <[email hidden]>,

Werehatrack said:

On Fri, 11 Apr 2008 07:08:38 GMT, Ryan Cousineau <[email hidden]>

may have said:

In article <[email hidden]>,

Werehatrack said:

On Thu, 10 Apr 2008 05:25:43 GMT, "Dave Mayer" <[email hidden]>
may have said:

>But this brings up the bigger question as to why not just appropriately
>maintain your hubs? An even better solution would be to get a hub that
>has
>a grease injection port. Then, maintenance would amount to a minute per
>year to squeeze some grease into the hub shell and wipe up the old stuff.

Too much grease increases drag, at least until enough is forced back
out for the grease packs to shear and develop gaps. The amount that
would be present after pumping in enough to actually repack the
bearings would be in that range easily.

If you can demonstrate it takes more than seconds of operation for this
to happen, I'll be impressed.

How much are you offering to pay for the bench time? The drag is
small, but everything-weenies being what they are, it would matter to
them. (Probably nobody else, though.) Choice of grease and design of
component might have a lot to do with the clearance time.

Quoted message said:

The first time the bearing is operated,
the balls go through the grease like, well, a bunch of bowling balls
through soft butter. If grease needs to be displaced for the balls to
move, it happens almost immediately. The grease has virtually no ability
to resist this displacement. It's also incompressible, and has little
propensity to flow or rebound, so it doesn't return to the bearing track
except as a thin film.

Unless, of course, the entire cavity is filled, in which case the
incompressibility means that the balls are running in a viscous
semifluid instead of freely. This is one of the reasons why
pump-lubed hubs are not as common as they used to be, while
aftermarket ball-and-socket joints typically still get supplied with
grease fittings. (The big reason, of course, is that with modern
lubricants and components, the bearings don't require the frequency of
re-lube that old ones needed.)

I recall being told that this used to be a topic in MechE studies;
point being that one should always allow clearance room for the excess
lube to exit. Merely adding a grease fitting to a conventional hub
design is not going to meet the spec.

Quoted message said:

Quoted message said:

Pumping in more grease also does not remove the contaminated grease
that's already present.

That's exactly what it does. Typical grease-injection hubs have a port
in the hub shell that admits grease into the axle area. the grease can
only flow from there through the bearing and then out the seals. When
clean grease is coming out of the outer seal, there is no place for
contaminated grease to be.

You've never taken one apart, then? It would be educational. The
contaminated grease will be everywhere that wasn't an active loaded
surface, and the clean grease will have flowed right past it.

Hm... Okay, I have a lot to learn here, but does this apply to Bearing
Buddy designs, too?

My sense is that at least in the local (rain-dominated) environment,
loss of grease is the fundamental killer of bearings. Lots of grease
prevents water from getting in.

Quoted message said:

Quoted message said:

You don't have to believe me. Grease-ported hubs are cheap: pump and see.

I used to work on them. I'm glad that modern hubs don't have grease
fittings.

--
Ryan Cousineau [email hidden] http://www.wiredcola.com/
"In other newsgroups, they killfile trolls."
"In rec.bicycles.racing, we coach them."

On Sat, 12 Apr 2008 05:46:50 GMT, Ryan Cousineau <[email hidden]>

may have said:

In article <[email hidden]>,
Werehatrack <[email hidden]> wrote:

Quoted message said:

Quoted message said:

You've never taken one apart, then? It would be educational. The
contaminated grease will be everywhere that wasn't an active loaded
surface, and the clean grease will have flowed right past it.

Hm... Okay, I have a lot to learn here, but does this apply to Bearing
Buddy designs, too?

Those hub covers that are peddled to boat trailer owners? The serious
fisherman of my acquaintance all started off swearing by them...and
ended up swearing *at* them. First off, trailer hubs either have
seals which are entirely ineffective at excluding water when the hub
is submerged (this is why the manufacturers uniformly warn NOT to
submerge the hubs) or you dare not install a Bearing Buddy. If the
hub uses a spring-loaded-lip seal, using the Bearing Buddy will
cheerfully cause the seal to be pumped right out of the hub. If the
seal is unloaded or felt, water will come in as easily as grease comes
out. Bottom line: Boat trailer owners learn to repack their bearings
every time they let the hubs get into the water. (Fresh water boaters
might get off easier on this, but most fishermen around here are going
out from a salt water ramp, and one maintenance lapse will put them by
the side of the road waiting for a spare hub and stub axle assembly on
the next trip.)

Quoted message said:

My sense is that at least in the local (rain-dominated) environment,
loss of grease is the fundamental killer of bearings. Lots of grease
prevents water from getting in.

Only to an extent, and usually not for long. Grease in motion with
water present will turn into a (usually corrosive) emulsion of water,
oil and soap. A bearing with just enough grease that the balls are
pretty much running free (which you noted will be the case for any
bearing that's been run for a short period in a hub that's not
completely air-excluded) is going to allow the water to come in direct
contact with the balls; the lube on the active bearing surfaces will
emulsify, and if the metals are easily corroded, that's what's going
to happen.

Quoted message said:

Quoted message said:

Quoted message said:

You don't have to believe me. Grease-ported hubs are cheap: pump and see.

I used to work on them. I'm glad that modern hubs don't have grease
fittings.

--
My email address is antispammed; pull WEEDS if replying via e-mail.
Typoes are not a bug, they're a feature.
Words processed in a facility that contains nuts.

Camilo said:

Rick Roof said:

Just installed ceramic bearings in my front wheel. The original
bearings seem much smoother. Is this just because the ceramics are
not broke in? They just don't seem as smooth as the bearings I took
out. I ended up putting the originals back in for now. Any info
would be appreciated. Thanks.

Rick

I'm wondering if anyone is going to even remotely answer your question
instead of highjacking it for a totally irrelevant discussion. Often
the argument starts with at least a disagreement on actual advice.
Didn't even get that far! I'm curious about your question so I will
stand by (but not hold my breath).

Wow, and how does this help?
Let me try, if the OP replaced only the bearing balls the races have to
brake in. The ceramics balls are harder en more spherical and have a
smoother surface than steel balls. The ceramics balls will hone the
races after a while.
If the OP installed a complete ball bearing the ceramic bearing should
be smooth from the beginning.

Lou

"Lou Holtman" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

That is the second stupiest way to maintain a hub. The first is not to
maintain the hub at all. You have to inject a ton of grease to push out
the
old dirty grease through the seal. Not very healthy for the seal. Choose a
hub that is easy (take apart and adjust afterwards) to maintain. Then you
maintain it more often. I vote for Campy hubs.

Lou

Lou: you run a bike shop that actively discourages your clients from doing
any maintenance on their bikes - right?

Anyway: I ran a set of inexpensive Campagnolo Tipo hubs for more than 30
years by injecting a little grease every few months. I overhauled them once
to see what was going on inside, and the races and balls were A-OK. I would
still be running them, but in a weak moment I sold the wheels to get a
70s-vintage set with Record hubs.

Unsealed Campy Record freewheel hubs is what I run on my rain commuter bike.
I ride these wheels 12 months a year, even in pouring rain. The hubs have
no seals. Seals are as good as keeping contaminants and water in contact
with the bearings as keeping them out.

After a downpour I spend a few minutes squeezing grease into the hub shells
and wiping up the excess.

So back to the initial purpose of this thread: using ceramic bearings in
bicycles is pointless, with no tangible benefits, designed only to extract
big $$ from the gullible.

Dave Mayer said:

"Lou Holtman" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

That is the second stupiest way to maintain a hub. The first is not to
maintain the hub at all. You have to inject a ton of grease to push out
the
old dirty grease through the seal. Not very healthy for the seal. Choose a
hub that is easy (take apart and adjust afterwards) to maintain. Then you
maintain it more often. I vote for Campy hubs.

Lou

Lou: you run a bike shop that actively discourages your clients from doing
any maintenance on their bikes - right?

No. I'm a mechanical engineer who rides a lot for a long time and did my
share of experimenting maintenance wise. My opinion is based on this. I
run Record hubs now ( 2002 and later) on all my road wheels. Injecting
grease leaves a mess (in freewheel mechanism ie) and, like Wherehatrack
mentioned, leaves a lot of contaminated grease where it is. I prefer to
take these apart, clean them and repack. It takes me half an hour per
wheelset. I do it once or twice a year. It is so easy, especially
adjusting the hubs afterwards, everyone learn that so there is no
reason/excuse not to so.

Quoted message said:

Anyway: I ran a set of inexpensive Campagnolo Tipo hubs for more than 30
years by injecting a little grease every few months. I overhauled them once
to see what was going on inside, and the races and balls were A-OK. I would
still be running them, but in a weak moment I sold the wheels to get a
70s-vintage set with Record hubs.

Good for you.
I run DT Swiss 240 hubs on all my ATB's and singlespeed which I use in
the winter on the road. As someone mentioned these are almost
maintenance free. Very good seals. For someone who rides a lot, hates
maintenance or is technical challenged I advise these hubs.

Quoted message said:

Unsealed Campy Record freewheel hubs is what I run on my rain commuter bike.
I ride these wheels 12 months a year, even in pouring rain. The hubs have
no seals. Seals are as good as keeping contaminants and water in contact
with the bearings as keeping them out.

Modern Record hubs have seals.

Quoted message said:

After a downpour I spend a few minutes squeezing grease into the hub shells
and wiping up the excess.

After a downpour, and we have our share of it in the Netherlands, I just
dry my bike. Repack once or twice a year is enough to keep my Record
hubs in A-OK condition.

Quoted message said:

So back to the initial purpose of this thread: using ceramic bearings in
bicycles is pointless, with no tangible benefits, designed only to extract
big $$ from the gullible.

Agreed.

Lou