How "sealed" are sealed bearings?
res09c5t
I've got a Phil bottom bracket with about 10,000 miles over three years
that I noticed was turning rough and almost sounded dry. Figuring that I
didn't have much to lose, I pulled it, popped off the seals on the bearings,
cleaned and re-greased them. It now seems a lot better- not perfect but
much improved. It's on a road bike that I generally don't ride under dirty
conditions and is very rarely in rain or wet- only when I get really
surprised. I have weighed in the 270-290 lb range most of the time I've
owned this BB.
My questions: I've always kind of assumed that sealed bearings could just
be ignored- nothing needed to be done and the Phil's would last almost
forever but I'm beginning to question this. Should I have some kind of
schedule to open, clean and grease these guys? Also, as I look at the
seals, they would keep most of the grease in, but I'm not so sure they can
keep dirt out?
Thanks in advance.
Lyle
Doug Huffman
is with incredibly expensive open-bearings in strategic mission-critical
applications.
The seal keeps only big dirt chunks out. As the bearing heats its internals
expand and the fluid (technical word - not just liquid) component extruded
out through the seal. When the bearing then cools whatever fluid may be
present outside is sucked into the interior to equalize pressure. This
might be clean lubricant or it might be dirty water or mud or saltwater or
whatever. The sealed bearing is now contaminated.
Phil Wood bearings cost IIRC $15. Common sealed bearings of the same size
and type cost about $5. They're changed in a few minutes and last a long
time.
"res09c5t" <res0...@verizon.net> wrote in message
news:duvna.27310$Zx.2...@nwrddc01.gnilink.net...
Robin Hubert
"Doug Huffman" <dhuf...@awod.com> wrote in message
news:b7m9d4$2d6id$1...@ID-77170.news.dfncis.de...
> I believe that sealed bearings should remain sealed. My primary
experience
> is with incredibly expensive open-bearings in strategic mission-critical
> applications.
Perhaps but the Phil bb isn't an incredibly expensive open-bearing in a
strategic mission-critical application. Opening them is a no-brainer.
> The seal keeps only big dirt chunks out. As the bearing heats its
internals
> expand and the fluid (technical word - not just liquid) component extruded
> out through the seal. When the bearing then cools whatever fluid may be
> present outside is sucked into the interior to equalize pressure. This
> might be clean lubricant or it might be dirty water or mud or saltwater or
> whatever. The sealed bearing is now contaminated.
None of this applies to bicycle bearings.
--
Robin Hubert <cv2...@earthlink.net>
Ed Ness
> >
> be ignored- nothing needed to be done and the Phil's would last almost
> forever but I'm beginning to question this. Should I have some kind of
> schedule to open, clean and grease these guys? Also, as I look at the
> seals, they would keep most of the grease in, but I'm not so sure they can
> keep dirt out?
>
> Thanks in advance.
> Lyle
From my experience,
"sealed bearings" = bearings with a rubber seal on them.
These rubber seals do HELP keep water out and grease in, but are not
foolproof. Not that I'm all that smart, but I've yet to see a "sealed
bearing" that did not get stiff after a few years of use without
servicing (Shimano cartridge bottom brackets excluded!).
I say, do the periodic service. Even King headsets (which are one of
the best in the business) require maintainace.
Ed
Ted
had to service them. They still run smooth. I ride under mostly dry
conditions, but on occasion get caught in the rain.
Ted
"res09c5t" <res0...@verizon.net> wrote in message news:<duvna.27310$Zx.2...@nwrddc01.gnilink.net>...
Doug Huffman
physics was cancelled for bicycles. Truly, the conspiracy of ignorance
masquerades as common sense.
"Robin Hubert" <cv2...@earthlink.net> wrote in message
news:pUyna.28961$4P1.2...@newsread2.prod.itd.earthlink.net...
muffa
You can have a look at www.keithbontrager.com
In one of his "rants" he discusses this subject extensivley.
cheers
muffa
in one of his "rants" he discusses this topic extensivley.
cheers
Bluto
> My questions: I've always kind of assumed that sealed bearings could just
> be ignored- nothing needed to be done and the Phil's would last almost
> forever but I'm beginning to question this.
Sealed bearing cartridges are somewhat unfortunately named to give the
superficial impression that the sealing is their unique and defining
feature. In fact they are no better sealed than any other mechanism
using a single rubber contact seal, meaning that they can be
infiltrated by water and contaminants under some conditions.
The chief merit of sealed bearing cartridges is that they are easily
and cheaply replaceable in their entirety once they have become
damaged or contaminated. A secondary benefit is that they are
routinely held to much tighter tolerances and higher finishes than the
cup & cone bearings otherwise used on bicycles.
Your bearings should be replaced. Whether you choose to use a Phil
Wood-certified bearing, a heavily greased bike-specific replacement,
or a generic industrially standard version is up to you.
> Should I have some kind of
> schedule to open, clean and grease these guys?
No, just inspect them periodically and replace as necessary. Don't be
too exuberant about cleaning them (e.g. don't spray them clean) as
this is likely to breach the seals and contaminate the bearings. If
you have ever used a high-pressure hose or even a garden spray nozzle
to clean your bike, this could be the reason that your bearings went
bad.
> Also, as I look at the
> seals, they would keep most of the grease in, but I'm not so sure they can
> keep dirt out?
The seals ooze a grease "lip" which attracts all kinds of crud, and in
principle it is possible that some smut could be drawn back inside the
bearing from this area. In practice it seems that the flow is all
from inside to outside and does not suck this junk back in. The stuff
must be pushed if it is to re-enter the bearing, as in the case of
spray washing or clumsy wiping. If the vicinity is so caked with
filth as to cause abrasion of the seal and a resultant gap, this too
could promote the introduction of contaminants into the grease.
Chalo Colina
Doug Taylor
>Have a look at www.keithbontrager.com
>in one of his "rants" he discusses this topic extensivley.
>cheers
That would be www.bontrager.com and specifically
www.bontrager.com/keith/rants.asp?id=26
--dt
Matt O'Toole
"muffa" <mu...@gmx.de> wrote in message
news:78ba8c4.03041...@posting.google.com...
> You can have a look at www.keithbontrager.com
> In one of his "rants" he discusses this subject
extensivley.
> cheers
This is probably the link you were looking for:
http://www.bontrager.com/keith/rants.asp?id=26
There's lots of other good stuff there too.
Matt O.
Tim McNamara
"Doug Huffman" <dhuf...@awod.com> wrote:
> I believe that sealed bearings should remain sealed. My primary
> experience is with incredibly expensive open-bearings in strategic
> mission-critical applications.
Sealed bearings shuld remain sealed. Phil and Co do not use sealed
bearings; they use cartridge bearings that look sealed, but the
"seals" are simple contact seals and do little more than keep the
grease from globbing out.
> The seal keeps only big dirt chunks out.
And they do this, too. But not water or other liquids, and not
contaminants suspended in liquid.
> As the bearing heats its internals expand and the fluid (technical
> word - not just liquid) component extruded out through the seal.
> When the bearing then cools whatever fluid may be present outside
> is sucked into the interior to equalize pressure. This might be
> clean lubricant or it might be dirty water or mud or saltwater or
> whatever. The sealed bearing is now contaminated.
And how fast does a bicyclist have to pedal to heat up the bearings to
the point where the bearing metals expand, the lubricant becomes
significantly less viscous, etc? A cadence of about 10,000 rpm or
more?
> Phil Wood bearings cost IIRC $15. Common sealed bearings of the
> same size and type cost about $5. They're changed in a few minutes
> and last a long time.
Not the bearings in a Phil BB. Those are a factory job to replace,
unlik ethe FSA hubs. But as the OP found out, it's a trivial matter
to pry loose the "seal" and regrease. Of course, standard bottom
brackets are also trivial to rebuild and it takes less time than
farting around with the Phil's cartidge "seals."
Jay Beattie
As a co-conspiring idiot, let me say this: you have to peel back the
wipers on Phil hubs and grease the bearings on a regular (but
infrequent) basis. They dry out quickly when ridden in rain. They are
not maintenance free unless you use them as a pencil holder. They are,
however, easier to maintain because there is no bearing adjustment. --
Jay Beattie.
B. Sanders
experience
> is with incredibly expensive open-bearings in strategic mission-critical
> applications.
Then why are you presuming that you know about bicycle bearing applications,
which are completely different?
> As the bearing heats its internals
> expand and the fluid (technical word - not just liquid) component extruded
> out through the seal. When the bearing then cools whatever fluid may be
> present outside is sucked into the interior to equalize pressure. This
> might be clean lubricant or it might be dirty water or mud or saltwater or
> whatever. The sealed bearing is now contaminated.
Mmmmkay... How much heat is generated by a cadence of, say 100rpm under
average bicycle crank loads? I'm going to hazard a guess that the bearings
stay very near ambient temperature, and that the grease does not change
viscosity in any measurable way. Do you have evidence to the contrary?
> Phil Wood bearings cost IIRC $15. Common sealed bearings of the same size
> and type cost about $5. They're changed in a few minutes and last a long
> time.
Phil is probably just marking up the $5 bearings and reselling them. Just a
guess. Either way, replacement seems to be an obvious solution. At that
price, I'd be hard pressed to bother with grease replacement, popping seals,
etc. Replacement is easy, and cheap. Heck I bought a whole stack of
silky-smooth ABEC-7 sealed bearings for about $1 each recently at Target.
They were sold as replacements for rollerblade bearings, not for Phil BB's;
but you get the idea.
-Barry
jobst....@stanfordalumni.org
>> You can have a look at www.keithbontrager.com In one of his "rants"
>> he discusses this subject extensivley.
> This is probably the link you were looking for:
http://www.bontrager.com/keith/rants.asp?id=26
> There's lots of other good stuff there too.
I disagree. Not only does this lengthy diatribe not give any
information on bearings and seals, it offers common anti academic
slurs we hear often enough here on wreck.bike. The essence of the
"sealed bearing" issue has been discussed here often, often enough
that the FAQ has an entry:
http://draco.acs.uci.edu/rbfaq/FAQ/8f.6.html
Jobst Brandt
jobst....@stanfordalumni.org
Palo Alto CA
jobst....@stanfordalumni.org
>> You can have a look at www.keithbontrager.com In one of his "rants"
>> he discusses this subject extensivley.
> This is probably the link you were looking for:
http://www.bontrager.com/keith/rants.asp?id=26
> There's lots of other good stuff there too.
I disagree. Not only does this lengthy diatribe not give any
information on bearings and seals, it offers common anti academic
slurs we hear often enough here on wreck.bike. The title of these web
pages as "Rants" is odd, although they are rants with little technical
content. I find the whole collection an embarrassing disclosure.
Matt O'Toole
<jobst....@stanfordalumni.org> wrote in message
news:5oFna.6397$JX2.4...@typhoon.sonic.net...
> I disagree. Not only does this lengthy diatribe not give
any
> information on bearings and seals, it offers common anti
academic
> slurs we hear often enough here on wreck.bike. The title
of these web
> pages as "Rants" is odd, although they are rants with
little technical
> content. I find the whole collection an embarrassing
disclosure.
I thought the V-brake article was pretty good.
I do think he was correct about the appeal of "sealed
bearing" hubs in bike shops. They seem "higher quality" to
people who don't know any better.
> The essence of the "sealed bearing" issue has been
discussed here
> often, often enough that the FAQ has an entry:
>
> http://draco.acs.uci.edu/rbfaq/FAQ/8f.6.html
'Struth, as they say in Oz.
Have you ever seen a bicycle hub with a good labrynth seal?
The only ones I've seen are on gear hubs like Sturmey
Archer. I had an early 80s Suntour bike a couple of years
ago. It had great labrynth seals on the freewheel. I don't
know why they don't use such seals on hubs -- it's such an
obviously perfect design. Probably cheap, too.
Not as good but the best I've seen so far are Shimano MTB
hubs from the last 6-7 years, with the rubber cups in
addition to the usual seals. I rarely need to service hubs
anymore, while it used to be a regular ritual. I have a
cheap Trek front hub with "sealed" bearings. I've had to
replace its bearings several times -- a real PITA compared
to servicing a regular hub, not to mention having to pay for
new bearings every time. It came with the bike, and as soon
as the rim wears out that wheel is going into the trash.
Trek probably stuck it on there because it has that kustom
hi kwality phat look, and is cheaper than a real Shimano
one.
"Sealed" bearings are used by companies who don't have the
ability to manufacture their own bearings, like Shimano and
Campy do. They just turn a hub on a lathe, and press in an
off the shelf bearing that was not really designed for
bicycle use.
IMO the best hubs are the cheapest Shimano ones that have
the rubber cups -- LX or Deore or whatever that is these
days. Anything "more" is just a waste of money, unless a
nicer finish is important to you.
Matt O.
Bluto
> "Robin Hubert" <cv2...@earthlink.net> wrote:
> >
> > "Doug Huffman" <dhuf...@awod.com> wrote:
> >
> > > The seal keeps only big dirt chunks out. As the bearing heats its internals
> > > expand and the fluid (technical word - not just liquid) component extruded
> > > out through the seal. When the bearing then cools whatever fluid may be
> > > present outside is sucked into the interior to equalize pressure. This
> > > might be clean lubricant or it might be dirty water or mud or saltwater or
> > > whatever. The sealed bearing is now contaminated.
> >
> > None of this applies to bicycle bearings.
> >
> Damn! No wonder JB has such a hard time here. I hadn't realized that
> physics was cancelled for bicycles. Truly, the conspiracy of ignorance
> masquerades as common sense.
Typical unhelpful, oblivious, blinkered jackassery from Doug Huffman.
Funny how this guy, who believes he knows better than everyone, never
has anything useful to offer.
How much bearing temperature rise to you expect to see from a maximum
perhaps 130rpm shaft speed at the bottom bracket? It ain't an
electric motor, you know. Anybody with even a flirting level of
experience and observation of sealed bearings on bicycles knows that
grease oozes out from shaft rotation alone (only if there's enough
fill grease in the bearing to ooze out at all) and does not appear to
suck back in any significant quantity. As I noted in my previous
post, contaminated grease must be pushed, squished, squirted, or blown
back into the bearing if it is to get in.
Chalo Colina
"The conspiracy of fatuousness masquerades as Doug Huffman"
Chris Zacho The Wheelman
they were, the thing wouldn't be able to turn.
So water (and microfine grit) can get inside. Also, the metal itself
does wear some, and that grit is no better that what makes it's way in
from outside.
Also lubricants, even grease, do evaporate after time. If you've ridden
in wet conditions, water can wash some out as well, depending on what
type you use. Which is why I pack all my bearings with waterproof boat
trailer wheel bearing grease, which is designed to be used in situations
where the entire bearing may be submerged (I still clean and repack them
at least once a year).
I bought a PW hub for my MTB in 1986. I still have it, it's still on the
original bearings. that's the original five year warranty met 3 1/2
times over. nearly 50,000 miles, mostly commuting (rain or shine) and
some off road miles, and yes, a few hub-deep stream crossings.
May you have the wind at your back.
And a really low gear for the hills!
Chris
Chris'Z Corner
"The Website for the Common Bicyclist":
http://www.geocities.com/czcorner
Chris Zacho The Wheelman
>"...This might be clean lubricant or it
>might be dirty water or mud or saltwater
>or whatever. The sealed bearing is now
>contaminated.
None of this applies to bicycle bearings."
Obviously, Mr Hubert doesn't live in a seaside community.....
jobst....@stanfordalumni.org
> Have you ever seen a bicycle hub with a good labyrinth seal? The
> only ones I've seen are on gear hubs like Sturmey Archer. I had an
> early 80s SunTour bike a couple of years ago. It had great
> labyrinth seals on the freewheel. I don't know why they don't use
> such seals on hubs -- it's such an obviously perfect design.
> Probably cheap, too.
I still ride those FW's (New Winner Pro) but they aren't as good as
they might be, because a labyrinth must have an air gap proportional
to the film strength of the fluid (water). The gap in this case is so
small it is reasonably close to a capillary. They are far more immune
to water than old freewheels that did not have such a seal.
> Not as good but the best I've seen so far are Shimano MTB hubs from
> the last 6-7 years, with the rubber cups in addition to the usual
> seals. I rarely need to service hubs anymore, while it used to be a
> regular ritual. I have a cheap Trek front hub with "sealed"
> bearings. I've had to replace its bearings several times -- a real
> PITA compared to servicing a regular hub, not to mention having to
> pay for new bearings every time. It came with the bike, and as soon
> as the rim wears out that wheel is going into the trash. Trek
> probably stuck it on there because it has that kustom hi kwality
> phat look, and is cheaper than a real Shimano one.
There are many ways to make a good seal, especially ones that reject
splash water, the principal problem for most bicycle equipment. Under
water sealing is another problem entirely and should not affect the
equipment that 99% of bicyclists use. As with most bicycle design
problems, the People solving them are not skilled engineers, but
rather bicycle repair shop mechanics who learned their skills through
apprenticeship, mostly unskilled in theory and test methods.
> "Sealed" bearings are used by companies who don't have the ability
> to manufacture their own bearings, like Shimano and Campy do. They
> just turn a hub on a lathe, and press in an off the shelf bearing
> that was not really designed for bicycle use.
Ah yes, but they believe in them unwittingly.
David Kunz
> I believe that sealed bearings should remain sealed. My primary experience
> is with incredibly expensive open-bearings in strategic mission-critical
> applications.
>
> The seal keeps only big dirt chunks out. As the bearing heats its internals
> expand and the fluid (technical word - not just liquid) component extruded
> out through the seal. When the bearing then cools whatever fluid may be
> present outside is sucked into the interior to equalize pressure. This
> might be clean lubricant or it might be dirty water or mud or saltwater or
> whatever. The sealed bearing is now contaminated.
My sealed wheel bearings were going every 4k miles or so. The wrench at
my LBS showed me how to grease 'em and now, with greasing every 1-2k
miles, I haven't replaced any yet -- 17k miles later.
David
Gary Young
[...]
> How much bearing temperature rise to you expect to see from a maximum
> perhaps 130rpm shaft speed at the bottom bracket? It ain't an
> electric motor, you know. Anybody with even a flirting level of
> experience and observation of sealed bearings on bicycles knows that
> grease oozes out from shaft rotation alone (only if there's enough
> fill grease in the bearing to ooze out at all) and does not appear to
> suck back in any significant quantity. As I noted in my previous
> post, contaminated grease must be pushed, squished, squirted, or blown
> back into the bearing if it is to get in.
This may be a stupid question, but why can't truly sealed bearings be
used in bicycle hubs? For instance, if I removed the rubber seals from
a motor bearing, added some extra grease and then welded metal covers
on, what would happen? My guess is that the bearing would distort or
even burst as the temperature increases, but your post seems to
suggest that that's not as big a problem as I had imagined. Even if it
is a problem, what if I put a few pinholes in the metal cover?
At bottom, my question is -- why can't we design a sealed or
semi-sealed bearing that is superior to motor bearings when used in a
bicycle. I suspect the answer has to do with manufacturing costs, but
if the industry could agree on a standard bearing size, it seems that
problem could be surmounted.
Doug Milliken
On Fri, 18 Apr 2003 jobst....@stanfordalumni.org wrote:
> Matt O'Toole writes:
> > "Sealed" bearings are used by companies who don't have the ability
> > to manufacture their own bearings, like Shimano and Campy do. They
> > just turn a hub on a lathe, and press in an off the shelf bearing
> > that was not really designed for bicycle use.
>
> Ah yes, but they believe in them unwittingly.
>
> Jobst Brandt
> jobst....@stanfordalumni.org
> Palo Alto CA
There is at least one partial exception to this -- Bullseye hubs have the
bearing bores finished with a precision broach, much more accurate and
repeatable than turning. The broaching operation is possible with his
design that has a 3-piece hubshell. Roger Durham told me once but I've
forgotten the exact figure, might be as good as a tenth of a thou' (of an
inch) (~0.0025mm).
This doesn't fix any of the problems with the single lip seals, but at
least the industrial bearings have the proper preload so they all turn
consistenly and smoothly.
Tim McNamara
Doug Milliken <bd...@bfn.org> wrote:
> There is at least one partial exception to this -- Bullseye hubs
> have the bearing bores finished with a precision broach, much more
> accurate and repeatable than turning. The broaching operation is
> possible with his design that has a 3-piece hubshell. Roger Durham
> told me once but I've forgotten the exact figure, might be as good
> as a tenth of a thou' (of an inch) (~0.0025mm).
Which reminds me- is Bullseye still in business? They apparently
moved shop in January (? this year?) but their Web site seems to be
gone and nothign new turns up via Google. The last I vaguely remember
hearing was that Roger Furham was in ill health.
Tim McNamara
garyy...@hotmail.com (Gary Young) wrote:
> chump...@hotmail.com (Bluto) wrote in message
> news:<8b4b7de4.03041...@posting.google.com>... [...]
>
> > How much bearing temperature rise to you expect to see from a
> > maximum perhaps 130rpm shaft speed at the bottom bracket? It
> > ain't an electric motor, you know. Anybody with even a flirting
> > level of experience and observation of sealed bearings on
> > bicycles knows that grease oozes out from shaft rotation alone
> > (only if there's enough fill grease in the bearing to ooze out at
> > all) and does not appear to suck back in any significant
> > quantity. As I noted in my previous post, contaminated grease
> > must be pushed, squished, squirted, or blown back into the
> > bearing if it is to get in.
>
> This may be a stupid question, but why can't truly sealed bearings
> be used in bicycle hubs? For instance, if I removed the rubber
> seals from a motor bearing, added some extra grease and then welded
> metal covers on, what would happen? My guess is that the bearing
> would distort or even burst as the temperature increases, but your
> post seems to suggest that that's not as big a problem as I had
> imagined. Even if it is a problem, what if I put a few pinholes in
> the metal cover?
It's a non-problem. Bicycle bearings remain at ambient temperature as
the rotational speed and loads are very low.
> At bottom, my question is -- why can't we design a sealed or
> semi-sealed bearing that is superior to motor bearings when used in
> a bicycle. I suspect the answer has to do with manufacturing costs,
> but if the industry could agree on a standard bearing size, it
> seems that problem could be surmounted.
The problem with truly sealed seals is that they are prone to causing
significant drag. This is a problem in such a low power environment.
There are some excellent seals in the bike industry, for example the
Sturmey Archer 3 speed hub seals are excellent- hubs that are 50 years
old can look like new inside despite being covered in the filth of
ages. Oddly enough, however, they leak oil *out* while preventing
ingress of water and contaminants.
Peter Cole
> semi-sealed bearing that is superior to motor bearings when used in a
> bicycle. I suspect the answer has to do with manufacturing costs, but
> if the industry could agree on a standard bearing size, it seems that
> problem could be surmounted.
This is all discussed in the FAQ. Additionally, there's a wealth of
information on the web about bearing seals, the problem is hardly limited to
the world of bicycles. For sealing out fluids, the typical solution is a
"labyrinth" seal. These have been used in bicycles.
Matt O'Toole
"Tim McNamara" <tim...@bitstream.net> wrote in message
news:timmcn-E5A70A....@gemini.visi.com...
> There are some excellent seals in the bike industry, for
example the
> Sturmey Archer 3 speed hub seals are excellent- hubs that
are 50 years
> old can look like new inside despite being covered in the
filth of
> ages. Oddly enough, however, they leak oil *out* while
preventing
> ingress of water and contaminants.
That's not odd at all. It's the way it's supposed to work.
Matt O.
Bluto
> chump...@hotmail.com (Bluto) wrote:
> > As I noted in my previous
> > post, contaminated grease must be pushed, squished, squirted, or blown
> > back into the bearing if it is to get in.
>
> This may be a stupid question, but why can't truly sealed bearings be
> used in bicycle hubs? For instance, if I removed the rubber seals from
> a motor bearing, added some extra grease and then welded metal covers
> on, what would happen? My guess is that the bearing would distort or
> even burst as the temperature increases, but your post seems to
> suggest that that's not as big a problem as I had imagined. Even if it
> is a problem, what if I put a few pinholes in the metal cover?
>
> At bottom, my question is -- why can't we design a sealed or
> semi-sealed bearing that is superior to motor bearings when used in a
> bicycle. I suspect the answer has to do with manufacturing costs, but
> if the industry could agree on a standard bearing size, it seems that
> problem could be surmounted.
Metal shielded bearing cartridges are quite common; they bear the
suffix "ZZ" on their size code. But ZZ double-shielded bearings are
not as tightly sealed as 2RS double rubber sealed bearings, though
they are slightly freer-spinning. There is a tiny gap where the metal
shield approaches the inner bearing race, whereas a rubber shield
makes contact with the race.
There are three issues I can think of:
1) seal drag
2) size constraints
3) standardization constraints
Still, there's nothing keeping anybody from making a bike-specific
bearing format-- say, full complement, full grease fill, and a rubber
contact seal behind a labyrinth seal.
But bearing cartridges are disposable items, why add more features to
them? Instead, an external seal can be added to the component,
screeening out most any potential contaminant before it even reaches
the bearing seal. In such a way a hub like this one
http://harriscyclery.net/site/page.cfm?PageID=49&SKU=HU6200
can run for years without the slightest bit of maintenance. I put one
on my sweetheart's bike five years ago, and it has yet to need any
attention, despite lots of miles and lots of wet Seattle riding. The
rubber cover is a little bit draggy when turned with the fingers, but
underneath, the axle end is clean.
One of my bikes has hubs that are identical except that the rubber
covers are instead metal caps that have some clearance gap. Still,
they've needed nothing during an even longer service life.
One of the other astute features of these hubs is an axle-- like
Suzue's--made with precision ground bearing seats and shoulders, so
that there is no bearing preload adjustment. The bearing preload
can't be set wrong, so the bearings last indefinitely. IMO Sunrace's
sealed bearing hubs are among the best value to be had in bike
components.
Anyway, Shimano demontrated long ago with their MTB hubs that you can
take any old crappy hub bearing and keep it running clean and smooth
through the use of an external rubber boot. This technique works even
better with sealed bearing cartridges, which have some sealing of
their own.
Chalo Colina
Bluto
> Which reminds me- is Bullseye still in business? They apparently
> moved shop in January (? this year?) but their Web site seems to be
> gone and nothign new turns up via Google. The last I vaguely remember
> hearing was that Roger Furham was in ill health.
Stiil in biz last I checked, but moved out to the sticks:
Bullseye
57460 Encelia Drive
Yucca Valley CA 92284
Phone 800-874-0600
Chris Zacho The Wheelman
"At bottom, my question is -- why can't we design a sealed or
semi-sealed bearing that is superior to motor bearings when used in a
bicycle. I suspect the answer has to do with manufacturing costs, but if
the industry could agree on a standard bearing size, it seems that
problem could be surmounted. "
The bicycle industry? STANDARDIZE?!?!
BWAHAHAHAHAHAHA!!!!!!
jobst....@stanfordalumni.org
>>> "Sealed" bearings are used by companies who don't have the ability
>>> to manufacture their own bearings, like Shimano and Campy do.
>>> They just turn a hub on a lathe, and press in an off the shelf
>>> bearing that was not really designed for bicycle use.
>> Ah yes, but they believe in them unwittingly.
> There is at least one partial exception to this -- Bullseye hubs
> have the bearing bores finished with a precision broach, much more
> accurate and repeatable than turning. The broaching operation is
> possible with his design that has a 3-piece hubshell. Roger Durham
> told me once but I've forgotten the exact figure, might be as good
> as a tenth of a thou' (of an inch) (~0.0025mm).
All this attention to precision is a smoke screen. Rubber seals have
a large manufacturing tolerance of their own and a large coefficient
of thermal expansion. They are designed to absorb these dimensional
deviations (that are large compared to those of any metal parts) from
the norm. The failure of seals is as described in the FAQ, "the seal
that doesn't leak, leaks!" When seals cease to weep, they run dry and
destroy the contact lip. Therein lies the failure of seals. Of
course, even if the seal weeps, exposing the "outside" to water causes
an emulsion that reenters the lubricant pool inside the seal.
> This doesn't fix any of the problems with the single lip seals, but
> at least the industrial bearings have the proper preload so they all
> turn consistently and smoothly.
Seal preload is not a critical parameter to the extent that it affects
bearings of various precision qualities. "Rubber" easily makes up any
differences.
Doug Milliken
I visited Roger Durham in late Feb this year, he was fine, the desert air
seems to suit. Telephone is the way to reach him. As has been mentioned
here before, the website was not a good match for his small business--very
hard to get anyone to deal with the email.
I bought a hub from him to be used in an Electrathon vehicle (small
electric race car)--turns just as smoothly as Bullseye hubs always have.
** To Jobst -- maybe I wasn't clear. The preload on the bearings
(carefully controlled in Bullseye hubs) is to get the bearings to work
correctly. If you've ever mounted cartridge bearings (in any machine) you
know that if the preload/press-fit is wrong they are either loose or they
bind.
I ended my other post with the note that this precision mounting does
nothing to change the rubber lip seals.
-- Doug Milliken
Tim McNamara
Ah. Well, from the crud and oil all over the spokes of my old 3-speed
from days of yore, the seals worked properly, then!
Matt O'Toole
> Ah. Well, from the crud and oil all over the spokes of my
old 3-speed
> from days of yore, the seals worked properly, then!
Yeah, I used to have one of those old Campy bikes with oil
holes in the hubs. Everyone thought I was crazy for
repacking them with grease (slows you down, you know), but
there was a method to my madness.
Matt O.
Mark McMaster
> The failure of seals is as described in the FAQ, "the seal
> that doesn't leak, leaks!" When seals cease to weep, they run dry and
> destroy the contact lip. Therein lies the failure of seals. Of
> course, even if the seal weeps, exposing the "outside" to water causes
> an emulsion that reenters the lubricant pool inside the seal.
How about the rubber lip seals on grease injectable
bearings, such as the old Suntour
"Grease Guard" system? These components have a grease
injection fitting on inner side of each bearing, and a
rubber lip seal on the outer side that is designed to allow
excess grease to ooze out. Injecting grease into the
bearing is intended to both replenish the grease, and to
push out dirt and the old contaminated grease.
I have used several Grease Guard components (hubs, bottom
brackets, pedals) and have found that, while it doesn't
completely eliminate problems of water/dirt entry, with
regular grease injection it does seem to prolong bearing
life and extend time between servicing the bearings as
compared to other bearing sealing systems (including
labyrinth seals).
Mark McMaster
MMc...@ix.netcom.com
Don
I am in the market for a new floor pump. Has anyone had a chance to
review the new Park PFP-2 pump. It appears to have some nice features.
A Muzi
>
> I am in the market for a new floor pump. Has anyone had a chance to
> review the new Park PFP-2 pump. It appears to have some nice features.
I'm not much on Park products generally but that is one exceptional piece!
Do go try one at your LBS. You'll be amazed at how nice it is. I was. Hard
to get excited about a floor pump but this really is wonderful.
--
Andrew Muzi
http://www.yellowjersey.org
Open every day since 1 April 1971
jobst....@stanfordalumni.org
>> The failure of seals is as described in the FAQ, "the seal that
>> doesn't leak, leaks!" When seals cease to weep, they run dry and
>> destroy the contact lip. Therein lies the failure of seals. Of
>> course, even if the seal weeps, exposing the "outside" to water
>> causes an emulsion that reenters the lubricant pool inside the
>> seal.
> How about the rubber lip seals on grease injectable bearings, such
> as the old SunTour "Grease Guard" system? These components have a
> grease injection fitting on inner side of each bearing, and a rubber
> lip seal on the outer side that is designed to allow excess grease
> to ooze out. Injecting grease into the bearing is intended to both
> replenish the grease, and to push out dirt and the old contaminated
> grease.
That was the old belief in the grease rack in gas stations. Grease
gets dirty only if the seals fail, if there are any. Today, no one
greases cars because the bearings are protected against dirt intrusion
and grease loss so they don't need replenishment. When was the last
time you took a car in for a chassis lube?
> I have used several Grease Guard components (hubs, bottom brackets,
> pedals) and have found that, while it doesn't completely eliminate
> problems of water/dirt entry, with regular grease injection it does
> seem to prolong bearing life and extend time between servicing the
> bearings as compared to other bearing sealing systems (including
> labyrinth seals).
It may work but that's not the way to go about it. Besides, this does
nothing for water intrusion and that was the original proposition,
that sealed bearings were water tight.
Doug Milliken
> Mark McMaster writes:
>
> > How about the rubber lip seals on grease injectable bearings, such
> > as the old SunTour "Grease Guard" system? These components have a
> That was the old belief in the grease rack in gas stations. Grease
> gets dirty only if the seals fail, if there are any. Today, no one
> greases cars because the bearings are protected against dirt intrusion
> and grease loss so they don't need replenishment. When was the last
> time you took a car in for a chassis lube?
More specifically, most automotive suspension bearings are now bonded
rubber bushings with no metal-on-metal (nothing to lubricate). As well as
eliminating lubrication, this also improves road noise isolation.
To get back to bicycles, Moulton uses bonded rubber bushings for the
suspension pivots in his New Series bikes. These were developed using
fatigue-rig testing. So far as I know, they have been trouble-free (on
the road for about 4-5 years now).
The remaining automotive bearings are, as you say "sealed for life". This
has varying degrees of success:
My parents had a Chrysler (mid 1990's) that went through three steering
tie rods joints in 90K miles/7 years (they were not happy). In this case,
if it were possible to do a quick "grease job" at oil change time it
could have saved them a lot of money compared to replacing the entire tie
rod when one end failed.
My Toyota is still on the original set (at similar milage and 11
years)--I will guess that Toyota used higher quality seals.