Lazerlite rear hub

[[email protected]]

While servicing the hub, I am not sure what lube to use so the pawls
all work like they should. Must I pack them with grease or is oil OK.
will the rubber seal go hard if I ues any grease or must I use a
specific rubber friedly grease?

[daveornee]

Wrote:
> While servicing the hub, I am not sure what lube to use so the pawls
> all work like they should. Must I pack them with grease or is oil OK.
> will the rubber seal go hard if I ues any grease or must I use a
> specific rubber friedly grease?
http://www.parktool.com/repair/readhowto.asp?id=45


--
daveornee

[Phil, Squid-in-Training]

wrote:
> While servicing the hub, I am not sure what lube to use so the pawls
> all work like they should. Must I pack them with grease or is oil OK.
> will the rubber seal go hard if I ues any grease or must I use a
> specific rubber friedly grease?

Don't use oil... it's too thin. My Laser Lite hub works fine with
bicycle-specific grease such as Finish Line or Park.
--
Phil, Squid-in-Training

[Phil, Squid-in-Training]

Pat Lamb wrote:
> Phil, Squid-in-Training wrote:
>> wrote:
>>> While servicing the hub, I am not sure what lube to use so the pawls
>>> all work like they should. Must I pack them with grease or is oil
>>> OK. will the rubber seal go hard if I ues any grease or must I use a
>>> specific rubber friedly grease?
>>
>> Don't use oil... it's too thin. My Laser Lite hub works fine with
>> bicycle-specific grease such as Finish Line or Park.
>
> Are you sure? Note the OP says he's lubing the _pawls_. I agree with
> grease for the bearings, but everything I've read or heard advocates
> oil for the pawls.
>
> Pat

Mine had grease all over them when I opened them up. Works fine.
--
Phil, Squid-in-Training

[john]

BBBut you are in Flordia, eh?

[[email protected]]

Phil Lee writes:

>> While servicing the hub, I am not sure what lube to use so the
>> pawls all work like they should. Must I pack them with grease or
>> is oil OK. will the rubber seal go hard if I use any grease or
>> must I use a specific rubber friendly grease?

If the seals in the hub are not designed to be used with hydrocarbon
lubricants, your hub is toast. Who makes these things anyway? They
seem to be shy and don't readily show up on a web search.

> Don't use oil... it's too thin. My Laser Lite hub works fine with
> bicycle-specific grease such as Finish Line or Park.

In what way is oil "to thin?" As has been mentioned often, grease is
oil in a "pudding" and has a viscosity that does not correlate to the
grease stiffness. Your grease has an oil viscosity that defines its
lubrication flow. That is also not directly related to film strength
in boundary layer lubrication.

So back to the question. What makes you sure that oil should not be
used?

Jobst Brandt

[Phil, Squid-in-Training]

wrote:
> Phil Lee writes:
>
>>> While servicing the hub, I am not sure what lube to use so the
>>> pawls all work like they should. Must I pack them with grease or
>>> is oil OK. will the rubber seal go hard if I use any grease or
>>> must I use a specific rubber friendly grease?
>
> If the seals in the hub are not designed to be used with hydrocarbon
> lubricants, your hub is toast. Who makes these things anyway? They
> seem to be shy and don't readily show up on a web search.
>
>> Don't use oil... it's too thin. My Laser Lite hub works fine with
>> bicycle-specific grease such as Finish Line or Park.
>
> In what way is oil "to thin?" As has been mentioned often, grease is
> oil in a "pudding" and has a viscosity that does not correlate to the
> grease stiffness. Your grease has an oil viscosity that defines its
> lubrication flow. That is also not directly related to film strength
> in boundary layer lubrication.
>
> So back to the question. What makes you sure that oil should not be
> used?

Ugh... all these big words. The oil won't keep water out as well as grease
will. Do I get a prize?

--
Phil, Squid-in-Training

[Phil, Squid-in-Training]

Pat Lamb wrote:
> Phil, Squid-in-Training wrote:
>> wrote:
>>> While servicing the hub, I am not sure what lube to use so the pawls
>>> all work like they should. Must I pack them with grease or is oil
>>> OK. will the rubber seal go hard if I ues any grease or must I use a
>>> specific rubber friedly grease?
>>
>> Don't use oil... it's too thin. My Laser Lite hub works fine with
>> bicycle-specific grease such as Finish Line or Park.
>
> Are you sure? Note the OP says he's lubing the _pawls_. I agree with
> grease for the bearings, but everything I've read or heard advocates
> oil for the pawls.

I didn't read what you said carefully. The design of this hub (an American
Classic design licensed to WTB) is such that water seems to take the path of
the spokes and once it ends up on the hubs, it drips directly on the seal
that leads to the inside of the pawl area.

Take a look here. This is an American Classic Ultralight rear road hub
which is very similar to the LaserDisc Lite:
http://plaza.ufl.edu/phillee/rbt/wtb1.jpg
http://plaza.ufl.edu/phillee/rbt/wtb2.jpg

That's my hub as I opened it.

--
Phil, Squid-in-Training

[[email protected]]

Phil Lee writes:

>>>> While servicing the hub, I am not sure what lube to use so the
>>>> pawls all work like they should. Must I pack them with grease or
>>>> is oil OK. will the rubber seal go hard if I use any grease or
>>>> must I use a specific rubber friendly grease?

>> If the seals in the hub are not designed to be used with
>> hydrocarbon lubricants, your hub is toast. Who makes these things
>> anyway? They seem to be shy and don't readily show up on a web
>> search.

>>> Don't use oil... it's too thin. My Laser Lite hub works fine with
>>> bicycle-specific grease such as Finish Line or Park.

>> In what way is oil "to thin?" As has been mentioned often, grease
>> is oil in a "pudding" and has a viscosity that does not correlate
>> to the grease stiffness. Your grease has an oil viscosity that
>> defines its lubrication flow. That is also not directly related to
>> film strength in boundary layer lubrication.

>> So back to the question. What makes you sure that oil should not
>> be used?

> Ugh... all these big words. The oil won't keep water out as well as
> grease will. Do I get a prize?

No. If you visualize the grease as being static, as on a seatpost,
where it is often used to prevent water intrusion, you are using the
wrong model. The hub-to-axle joint rotates and "stirs" the grease and
any water on its surface into an ice cream like paste. That is, the
grease transports water into the hub if exposed to water. The oil in
the grease emulsifies and in time can homogenize.

To keep water out, either a double lipped seal with a drained central
gap, or a labyrinth seal such as Sturmey-Archer hubs and many
Ashtabula BB's have, is required. These drain water out the bottom by
gravity, much as the eaves on a house do.

|------
| |----|
|----| |
| |
| |
----| |----

- - - - - - - - - - - How this prevents splash water intrusion should
be apparent.
----| |----
| |
| |
|----| |
| |----|
|------

The gaps must be large enough not to act as capillaries, something
that SunTour freewheels failed to do and are, therefore, not as
weather proof as they were designed to be having half mm gap labyrinth
seals that are visible as brass rings on the back side and hidden
under the cone. It was a nice gesture though and works sort-of.

http://www.sheldonbrown.com/brandt/sealed-bearings.html

From your response, I take it you are guessing about which lubricants
are effective and how. You might add that disclaimer before giving
advice on lubrication.

Jobst Brandt

[[email protected]]

Phil Lee writes:

>>>> While servicing the hub, I am not sure what lube to use so the
>>>> pawls all work like they should. Must I pack them with grease or
>>>> is oil OK. Will the rubber seal go hard if I use any grease or
>>>> must I use a specific rubber friendly grease?

>>> Don't use oil... it's too thin. My Laser Lite hub works fine with
>>> bicycle-specific grease such as Finish Line or Park.

>> Are you sure? Note the OP says he's lubing the _pawls_. I agree
>> with grease for the bearings, but everything I've read or heard
>> advocates oil for the pawls.

> I didn't read what you said carefully. The design of this hub (an
> American Classic design licensed to WTB) is such that water seems to
> take the path of the spokes and once it ends up on the hubs, it
> drips directly on the seal that leads to the inside of the pawl
> area.

> Take a look here. This is an American Classic Ultralight rear road
> hub which is very similar to the LaserDisc Lite:

http://plaza.ufl.edu/phillee/rbt/wtb1.jpg
http://plaza.ufl.edu/phillee/rbt/wtb2.jpg

> That's my hub as I opened it.

Holy grease ball, how many pawls (6?) does this thing use and how many
ramps does the ratchet have? Do you have a picture of a cleaned pawl?
Since the whole assembly is covered in grease, not much detail is
discernible, like the shape of the greasy ring in picture one and with
what it meshes on the hub.

I find amazing that no Mfr. shows a cross section view of his
product. The last good ones I can recall are old Campagnolo and
Sturmey-Archer hubs. An isometric 3-D picture doesn't reveal how
things work. It's just a pretty picture.

Jobst Brandt

[Phil, Squid-in-Training]

wrote:
> Phil Lee writes:
>
>>>>> While servicing the hub, I am not sure what lube to use so the
>>>>> pawls all work like they should. Must I pack them with grease or
>>>>> is oil OK. Will the rubber seal go hard if I use any grease or
>>>>> must I use a specific rubber friendly grease?
>
>>>> Don't use oil... it's too thin. My Laser Lite hub works fine with
>>>> bicycle-specific grease such as Finish Line or Park.
>
>>> Are you sure? Note the OP says he's lubing the _pawls_. I agree
>>> with grease for the bearings, but everything I've read or heard
>>> advocates oil for the pawls.
>
>> I didn't read what you said carefully. The design of this hub (an
>> American Classic design licensed to WTB) is such that water seems to
>> take the path of the spokes and once it ends up on the hubs, it
>> drips directly on the seal that leads to the inside of the pawl
>> area.
>
>> Take a look here. This is an American Classic Ultralight rear road
>> hub which is very similar to the LaserDisc Lite:
>
> http://plaza.ufl.edu/phillee/rbt/wtb1.jpg
> http://plaza.ufl.edu/phillee/rbt/wtb2.jpg
>
>> That's my hub as I opened it.
>
> Holy grease ball, how many pawls (6?) does this thing use

I think it's six.

> and how many
> ramps does the ratchet have?

The freehub body has the ratchets on it. I think I counted 25 or 26.

> Do you have a picture of a cleaned pawl?

I didn't clean it because I was replacing the recalled clutch plate... it
was a brand-new hub.

> Since the whole assembly is covered in grease, not much detail is
> discernible, like the shape of the greasy ring in picture one and with
> what it meshes on the hub.

The greasy ring in picture one is metal with a rubber backing on it. It is
assembled in picture two as the rubbery-looking seal thingy on the main part
of the hub, covering the assembled pawls.

> I find amazing that no Mfr. shows a cross section view of his
> product. The last good ones I can recall are old Campagnolo and
> Sturmey-Archer hubs. An isometric 3-D picture doesn't reveal how
> things work. It's just a pretty picture.

I think that's a personal opinion. Isometric views show how things fit
together in 3D space along different planes, saving multiple views and
space/paper. Cross-sections can't do that.

--
Phil, Squid-in-Training

[[email protected]]

Phil Lee writes:

>>> Take a look here. This is an American Classic Ultralight rear
>>> road hub which is very similar to the LaserDisc Lite:

http://plaza.ufl.edu/phillee/rbt/wtb1.jpg
http://plaza.ufl.edu/phillee/rbt/wtb2.jpg

>>> That's my hub as I opened it.

>> Holy grease ball, how many pawls (6?) does this thing use

> I think it's six.

>> and how many ramps does the ratchet have?

> The freehub body has the ratchets on it. I think I counted 25 or 26.

That's unusual, with that number of ramps only one pawl would be
engaged at any time and the escapement would click either 150 or 156
times per revolution. I have not seen a bicycle with 2.3 degree
resolution. That's unusually fine. I can't imagine how that sounds
if the ratchet is audible.

>> Do you have a picture of a cleaned pawl?

> I didn't clean it because I was replacing the recalled clutch
> plate... it was a brand-new hub.

What is a clutch plate and is it visible in the pictures you list?

>> Since the whole assembly is covered in grease, not much detail is
>> discernible, like the shape of the greasy ring in picture one and
>> with what it meshes on the hub.

> The greasy ring in picture one is metal with a rubber backing on it.
> It is assembled in picture two as the rubbery-looking seal thingy on
> the main part of the hub, covering the assembled pawls.

Sounds like a designed water port to me.

>> I find amazing that no Mfr. shows a cross section view of his
>> product. The last good ones I can recall are old Campagnolo and
>> Sturmey-Archer hubs. An isometric 3-D picture doesn't reveal how
>> things work. It's just a pretty picture.

> I think that's a personal opinion. Isometric views show how things
> fit together in 3D space along different planes, saving multiple
> views and space/paper. Cross-sections can't do that.

I think you are thinking of an exploded view. A solid or even a
transparent isometric does not reveal anything but an idea of how the
device appears externally... like a photograph.

Jobst Brandt

[Lou Holtman]

Phil, Squid-in-Training wrote:
> Pat Lamb wrote:
>
>>Phil, Squid-in-Training wrote:
>>
wrote:
>>>
>>>>While servicing the hub, I am not sure what lube to use so the pawls
>>>>all work like they should. Must I pack them with grease or is oil
>>>>OK. will the rubber seal go hard if I ues any grease or must I use a
>>>>specific rubber friedly grease?
>>>
>>>Don't use oil... it's too thin. My Laser Lite hub works fine with
>>>bicycle-specific grease such as Finish Line or Park.
>>
>>Are you sure? Note the OP says he's lubing the _pawls_. I agree with
>>grease for the bearings, but everything I've read or heard advocates
>>oil for the pawls.
>>
>>Pat
>
>
> Mine had grease all over them when I opened them up. Works fine.


Even when it's (really) cold?

Lou
--
Posted by news://news.nb.nu

[Luns Tee]

In article >,
> wrote:
>>> and how many ramps does the ratchet have?
>> The freehub body has the ratchets on it. I think I counted 25 or 26.

>That's unusual, with that number of ramps only one pawl would be
>engaged at any time and the escapement would click either 150 or 156
>times per revolution. I have not seen a bicycle with 2.3 degree
>resolution. That's unusually fine. I can't imagine how that sounds
>if the ratchet is audible.

http://plaza.ufl.edu/phillee/rbt/wtb2.jpg

I count 24 on the freehub body. It'd be 24 clicks, with all six
pawls clicking in sync.


-Luns

[Sandy]

Dans le message de ,
> a
réfléchi, et puis a déclaré :
> Phil Lee writes:
>
>>>> Take a look here. This is an American Classic Ultralight rear
>>>> road hub which is very similar to the LaserDisc Lite:
>
> http://plaza.ufl.edu/phillee/rbt/wtb1.jpg
> http://plaza.ufl.edu/phillee/rbt/wtb2.jpg
>
>>>> That's my hub as I opened it.
>
>>> Holy grease ball, how many pawls (6?) does this thing use
>
>> I think it's six.
>
>>> and how many ramps does the ratchet have?
>
>> The freehub body has the ratchets on it. I think I counted 25 or 26.
>
> That's unusual, with that number of ramps only one pawl would be
> engaged at any time and the escapement would click either 150 or 156
> times per revolution. I have not seen a bicycle with 2.3 degree
> resolution. That's unusually fine. I can't imagine how that sounds
> if the ratchet is audible.
>
>>> Do you have a picture of a cleaned pawl?
>
>> I didn't clean it because I was replacing the recalled clutch
>> plate... it was a brand-new hub.
>
> What is a clutch plate and is it visible in the pictures you list?

http://www.amclassic.com/tech/pdf/AmClassicCamPlatePg1.jpg

http://www.amclassic.com/tech/pdf/AmClassicCamPlatePg2.jpg
--
Sandy
Verneuil-sur-Seine
*******

La vie, c'est comme une bicyclette,
il faut avancer pour ne pas perdre l'équilibre.
-- Einstein, A.

[RonSonic]

On Fri, 17 Mar 2006 23:12:46 -0500, "Phil, Squid-in-Training"
> wrote:

wrote:
>> Phil Lee writes:
>>
>>>> While servicing the hub, I am not sure what lube to use so the
>>>> pawls all work like they should. Must I pack them with grease or
>>>> is oil OK. will the rubber seal go hard if I use any grease or
>>>> must I use a specific rubber friendly grease?
>>
>> If the seals in the hub are not designed to be used with hydrocarbon
>> lubricants, your hub is toast. Who makes these things anyway? They
>> seem to be shy and don't readily show up on a web search.
>>
>>> Don't use oil... it's too thin. My Laser Lite hub works fine with
>>> bicycle-specific grease such as Finish Line or Park.
>>
>> In what way is oil "to thin?" As has been mentioned often, grease is
>> oil in a "pudding" and has a viscosity that does not correlate to the
>> grease stiffness. Your grease has an oil viscosity that defines its
>> lubrication flow. That is also not directly related to film strength
>> in boundary layer lubrication.
>>
>> So back to the question. What makes you sure that oil should not be
>> used?
>
>Ugh... all these big words. The oil won't keep water out as well as grease
>will. Do I get a prize?

Only runner-up. He scored all the bonus points available with "grease is oil in
a 'pudding.'"

Ron

[Phil, Squid-in-Training]

Lou Holtman wrote:
> Phil, Squid-in-Training wrote:
>> Pat Lamb wrote:
>>
>>> Phil, Squid-in-Training wrote:
>>>
>>>> wrote:
>>>>
>>>>> While servicing the hub, I am not sure what lube to use so the
>>>>> pawls all work like they should. Must I pack them with grease or
>>>>> is oil OK. will the rubber seal go hard if I ues any grease or
>>>>> must I use a specific rubber friedly grease?
>>>>
>>>> Don't use oil... it's too thin. My Laser Lite hub works fine with
>>>> bicycle-specific grease such as Finish Line or Park.
>>>
>>> Are you sure? Note the OP says he's lubing the _pawls_. I agree
>>> with grease for the bearings, but everything I've read or heard
>>> advocates oil for the pawls.
>>>
>>> Pat
>>
>>
>> Mine had grease all over them when I opened them up. Works fine.
>
>
> Even when it's (really) cold?

That data point isn't on my radar, so that was an oversight on my part.
Currently it's 80 degrees outside here in FL.
--
Phil, Squid-in-Training

[Phil, Squid-in-Training]

Luns Tee wrote:
> In article >,
> > wrote:
>>>> and how many ramps does the ratchet have?
>>> The freehub body has the ratchets on it. I think I counted 25 or
>>> 26.
>
>> That's unusual, with that number of ramps only one pawl would be
>> engaged at any time and the escapement would click either 150 or 156
>> times per revolution. I have not seen a bicycle with 2.3 degree
>> resolution. That's unusually fine. I can't imagine how that sounds
>> if the ratchet is audible.
>
> http://plaza.ufl.edu/phillee/rbt/wtb2.jpg
>
> I count 24 on the freehub body. It'd be 24 clicks, with all six
> pawls clicking in sync.

Yes, it's 24 clicks per revolution. It's still loud as hell and sounds like
even more like a bees nest than CK hubs.

--
Phil, Squid-in-Training

[[email protected]]

Luns Tee writes:

>>>> and how many ramps does the ratchet have?

>>> The freehub body has the ratchets on it.
>>> I think I counted 25 or 26.

>> That's unusual, with that number of ramps only one pawl would be
>> engaged at any time and the escapement would click either 150 or
>> 156 times per revolution. I have not seen a bicycle with 2.3
>> degree resolution. That's unusually fine. I can't imagine how
>> that sounds if the ratchet is audible.

http://plaza.ufl.edu/phillee/rbt/wtb2.jpg

> I count 24 on the freehub body. It'd be 24 clicks, with all six
> pawls clicking in sync.

Ooh, that's the ratchet? That is the weirdest set of ratchet ramps
I've seen. This designer likes belt, suspenders, and elastic
waistband. Not only does he try to load six pawls at once, but each
of these seem to have double engagement. I also have never seen a
round nosed ratchet pawl either. It's an interesting concept. With
machining tolerances of pawl carrier, pawls, and ratchet, simultaneous
contact is doubtful even without axle flex. With it, only one pawl
will bear the load, the rest n=being along for the ride.

This has all been done ages ago but then no one at Regina or
SunTour. for that matter, published their work. Without the knowledge
of history, it must be repeated again and again and...

Jobst Brandt

[Luns Tee]

In article >,
> wrote:
>Ooh, that's the ratchet? That is the weirdest set of ratchet ramps
>I've seen. This designer likes belt, suspenders, and elastic
>waistband. Not only does he try to load six pawls at once, but each
>of these seem to have double engagement. I also have never seen a
>round nosed ratchet pawl either. It's an interesting concept. With
>machining tolerances of pawl carrier, pawls, and ratchet, simultaneous
>contact is doubtful even without axle flex. With it, only one pawl
>will bear the load, the rest n=being along for the ride.

Here's the patent:

http://tinyurl.com/jx3yy

Trying to share the load among six pawls aside, the excess
complication of this design (the cam plate) comes from fears that the
pawls might not all engage together - that is, at the instant of
resuming a forward torque, some pawls be still hung up on the ramp of
the previous tooth while the others have clicked and fallen into
place. This is a metastable situation and very improbable.

I think the rounded pawls are to dull the boundary between pawls
being on one tooth and clicking to engage the next one. If the boundary
is sharp, then manufacturing tolerances would mean it's still possible
for some pawls to have just passed onto engaging the next tooth while
others are left behind. Applying forward torque at this instant, the
engaged pawls will want to be drawn inwards, and through the cam plate,
would try to draw the other pawls inwards with them. The other pawls
still resting on previous teeth would result in the cam plate being
torn apart if the engaged pawls pull hard (this would depend on the
angle of the pawl tip to ratchet tooth contact). The blunted nose
gives a region in which this self-energizing action doesn't happen,
but in that case, six independantly spring pawls would behave no
differently.

On the other hand, I'm a little suprised that this design is
as noisy as people are saying. The return spring for the pawls seems
to be the spring on the cassette body pushing on the cam plate. While
freewheeling, this spring would be dragging across the cam plate
backwards, which should retract all six pawls from touching the
ratchet. Whatever ticking is heard, I think is from the spring
ratcheting on the cam plate, not from the pawls ticking on ratchet
teeth. This would be easily verified by just assembling the hub without
any pawls and seeing if it still spins as loud.

This ratchet does not need to support a substantial forward
load, so if it were just a friction drag coupling, the freehub could
be silent in coasting. But its operation would be very sensitive to
the presence of this drag, and with wear could very well end up
forward freewheeling. I think this is the opposite direction of what
this recall was about, though - I believe the new cam plate has more
defined teeth whereas silent operation would involve getting rid of
them.

Thinking about this during my ride today, I think that using a
different sort of linkage between pawls, and a suitably shaped ratchet,
it's possible to allow two pawls to share the drive torque. With a
little extra complication, three or possibly four pawls could share,
but I can't see it going beyond that. The metastablity problem would
still exist though, in which case only the engaged pawls again would
support the load. I'll describe it the structure later if there's any
interest.

-Luns

[Luns Tee]

In article >,
> wrote:
>Ooh, that's the ratchet? That is the weirdest set of ratchet ramps
>I've seen. This designer likes belt, suspenders, and elastic
>waistband. Not only does he try to load six pawls at once, but each
>of these seem to have double engagement. I also have never seen a
>round nosed ratchet pawl either. It's an interesting concept. With
>machining tolerances of pawl carrier, pawls, and ratchet, simultaneous
>contact is doubtful even without axle flex. With it, only one pawl
>will bear the load, the rest n=being along for the ride.

Here's the patent:

http://tinyurl.com/jx3yy

Trying to share the load among six pawls aside, the excess
complication of this design (the cam plate) comes from fears that the
pawls might not all engage together - that is, at the instant of
resuming a forward torque, some pawls be still hung up on the ramp of
the previous tooth while the others have clicked and fallen into
place. This is a metastable situation and very improbable.

I think the rounded pawls are to dull the boundary between pawls
being on one tooth and clicking to engage the next one. If the boundary
is sharp, then manufacturing tolerances would mean it's still possible
for some pawls to have just passed onto engaging the next tooth while
others are left behind. Applying forward torque at this instant, the
engaged pawls will want to be drawn inwards, and through the cam plate,
would try to draw the other pawls inwards with them. The other pawls
still resting on previous teeth would result in the cam plate being
torn apart if the engaged pawls pull hard (this would depend on the
angle of the pawl tip to ratchet tooth contact). The blunted nose
gives a region in which this self-energizing action doesn't happen,
but in that case, six independantly spring pawls would behave no
differently.

On the other hand, I'm a little suprised that this design is
as noisy as people are saying. The return spring for the pawls seems
to be the spring on the cassette body pushing on the cam plate. While
freewheeling, this spring would be dragging across the cam plate
backwards, which should retract all six pawls from touching the
ratchet. Whatever ticking is heard, I think is from the spring
ratcheting on the cam plate, not from the pawls ticking on ratchet
teeth. This would be easily verified by just assembling the hub without
any pawls and seeing if it still spins as loud.

This ratchet does not need to support a substantial forward
load, so if it were just a friction drag coupling, the freehub could
be silent in coasting. But its operation would be very sensitive to
the presence of this drag, and with wear could very well end up
forward freewheeling. I think this is the opposite direction of what
this recall was about, though - I believe the new cam plate has more
defined teeth whereas silent operation would involve getting rid of
them.

Thinking about this during my ride today, I think that using a
different sort of linkage between pawls, and a suitably shaped ratchet,
it's possible to allow two pawls to share the drive torque. With a
little extra complication, three or possibly four pawls could share,
but I can't see it going beyond that. The metastablity problem would
still exist though, in which case only the engaged pawls again would
support the load. I'll describe it the structure later if there's any
interest.

-Luns

[Phil, Squid-in-Training]

Luns Tee wrote:
> In article >,
> > wrote:
>> Ooh, that's the ratchet? That is the weirdest set of ratchet ramps
>> I've seen. This designer likes belt, suspenders, and elastic
>> waistband. Not only does he try to load six pawls at once, but each
>> of these seem to have double engagement. I also have never seen a
>> round nosed ratchet pawl either. It's an interesting concept. With
>> machining tolerances of pawl carrier, pawls, and ratchet,
>> simultaneous contact is doubtful even without axle flex. With it,
>> only one pawl will bear the load, the rest n=being along for the
>> ride.
>
> Here's the patent:
>
> http://tinyurl.com/jx3yy
>
> Trying to share the load among six pawls aside, the excess
> complication of this design (the cam plate) comes from fears that the
> pawls might not all engage together - that is, at the instant of
> resuming a forward torque, some pawls be still hung up on the ramp of
> the previous tooth while the others have clicked and fallen into
> place. This is a metastable situation and very improbable.
>
> I think the rounded pawls are to dull the boundary between pawls
> being on one tooth and clicking to engage the next one. If the
> boundary is sharp, then manufacturing tolerances would mean it's
> still possible for some pawls to have just passed onto engaging the
> next tooth while others are left behind. Applying forward torque at
> this instant, the engaged pawls will want to be drawn inwards, and
> through the cam plate, would try to draw the other pawls inwards with
> them. The other pawls still resting on previous teeth would result in
> the cam plate being torn apart if the engaged pawls pull hard (this
> would depend on the angle of the pawl tip to ratchet tooth contact).
> The blunted nose gives a region in which this self-energizing action
> doesn't happen, but in that case, six independantly spring pawls
> would behave no differently.
>
> On the other hand, I'm a little suprised that this design is
> as noisy as people are saying. The return spring for the pawls seems
> to be the spring on the cassette body pushing on the cam plate. While
> freewheeling, this spring would be dragging across the cam plate
> backwards, which should retract all six pawls from touching the
> ratchet. Whatever ticking is heard, I think is from the spring
> ratcheting on the cam plate, not from the pawls ticking on ratchet
> teeth. This would be easily verified by just assembling the hub
> without any pawls and seeing if it still spins as loud.
>
> This ratchet does not need to support a substantial forward
> load, so if it were just a friction drag coupling, the freehub could
> be silent in coasting. But its operation would be very sensitive to
> the presence of this drag, and with wear could very well end up
> forward freewheeling. I think this is the opposite direction of what
> this recall was about, though - I believe the new cam plate has more
> defined teeth whereas silent operation would involve getting rid of
> them.

Bravo - the situation is exactly as you describe. The replacement cam plate
had teeth that were stamped on both sides, whereas the old cam plate was
stamped only on one side.

http://plaza.ufl.edu/phillee/rbt/wtb3.jpg
http://plaza.ufl.edu/phillee/rbt/wtb4.jpg

New one on the right, old one on the left. After replacing the cam plate,
the ticks got much louder, and the corresponding drag from freewheeling also
increased.

> Thinking about this during my ride today, I think that using a
> different sort of linkage between pawls, and a suitably shaped
> ratchet, it's possible to allow two pawls to share the drive torque.
> With a little extra complication, three or possibly four pawls could
> share, but I can't see it going beyond that. The metastablity problem
> would still exist though, in which case only the engaged pawls again
> would support the load. I'll describe it the structure later if
> there's any interest.
>
> -Luns

--
Phil, Squid-in-Training

[[email protected]]

Luns Tee writes:

>> Ooh, that's the ratchet? That is the weirdest set of ratchet ramps
>> I've seen. This designer likes belt, suspenders, and elastic
>> waistband. Not only does he try to load six pawls at once, but
>> each of these seem to have double engagement. I also have never
>> seen a round nosed ratchet pawl either. It's an interesting
>> concept. With machining tolerances of pawl carrier, pawls, and
>> ratchet, simultaneous contact is doubtful even without axle flex.
>> With it, only one pawl will bear the load, the rest being along for
>> the ride.

> Here's the patent:

http://tinyurl.com/jx3yy

> Trying to share the load among six pawls aside, the excess
> complication of this design (the cam plate) comes from fears that
> the pawls might not all engage together - that is, at the instant of
> resuming a forward torque, some pawls be still hung up on the ramp
> of the previous tooth while the others have clicked and fallen into
> place. This is a metastable situation and very improbable.

> I think the rounded pawls are to dull the boundary between pawls
> being on one tooth and clicking to engage the next one. If the
> boundary is sharp, then manufacturing tolerances would mean it's
> still possible for some pawls to have just passed onto engaging the
> next tooth while others are left behind. Applying forward torque at
> this instant, the engaged pawls will want to be drawn inward, and
> through the cam plate, would try to draw the other pawls inward with
> them. The other pawls still resting on previous teeth would result
> in the cam plate being torn apart if the engaged pawls pull hard
> (this would depend on the angle of the pawl tip to ratchet tooth
> contact). The blunted nose gives a region in which this
> self-energizing action doesn't happen, but in that case, six
> independently spring pawls would behave no differently.

Reading over the patent, I see the inventor had little if any
freewheel experience and envisions his designs as geometrically
perfect and of absolutely rigid material. As I mentioned, freewheels
of the past recognized that this was not so and designed around single
pawl engagement where one carries all... which it what happens anyway.
Partial engagement is the reason for failures in some of these designs
where engineers believed they were safe through multiple engagements.

> On the other hand, I'm a little surprised that this design is as
> noisy as people are saying. The return spring for the pawls seems
> to be the spring on the cassette body pushing on the cam plate.
> While freewheeling, this spring would be dragging across the cam
> plate backward, which should retract all six pawls from touching the
> ratchet. Whatever ticking is heard, I think is from the spring
> ratcheting on the cam plate, not from the pawls ticking on ratchet
> teeth. This would be easily verified by just assembling the hub
> without any pawls and seeing if it still spins as loud.

These things come and go over time, failing for either reliability or
economic problems. This one seems to have some complex machining
(expense) in contrast to freewheels of old, whose ratchet profiles and
pawls were finish forged. Besides, the big money is in selling OEM
groups, not replacement hubs.

> This ratchet does not need to support a substantial forward load, so
> if it were just a friction drag coupling, the freehub could be
> silent in coasting. But its operation would be very sensitive to
> the presence of this drag, and with wear could very well end up
> forward freewheeling. I think this is the opposite direction of
> what this recall was about, though - I believe the new cam plate has
> more defined teeth whereas silent operation would involve getting
> rid of them.

There are too many versions and embodiments in the patent for me to
see what is really in the hub in use. From the greasy stuff shown, it
seems to be a complicated structure as are the pawls and springs. Its
weather resistance looks poor as well.

> Thinking about this during my ride today, I think that using a
> different sort of linkage between pawls, and a suitably shaped
> ratchet, it's possible to allow two pawls to share the drive torque.
> With a little extra complication, three or possibly four pawls could
> share, but I can't see it going beyond that. The metastability
> problem would still exist though, in which case only the engaged
> pawls again would support the load. I'll describe it the structure
> later if there's any interest.

Just seeing the pawls makes me not want to have much to do with it.
My bicycle coasts noiselessly ad hasn't missed an engagement over the
years. The design problem arises because initially freehubs tried to
put the escapement inside the sprocket arbor, thereby reducing the
operating radius by half of what better freewheels used. This
required stinger pawls and ratchets as do the wall climbing gears
people use today.

The hub in question is not limited by the diameter of the sprocket
arbor so it seems to have a solution to a problem that is not present.
In any event, I am amazed at the clacking noises I hear with some
bicycles that are coasting. Since not all of them do so, it must be a
misunderstanding of the problem by the noisy ones.

Jobst Brandt

[jim beam]

wrote:
> Phil Lee writes:
>
>
>>>>>While servicing the hub, I am not sure what lube to use so the
>>>>>pawls all work like they should. Must I pack them with grease or
>>>>>is oil OK. will the rubber seal go hard if I use any grease or
>>>>>must I use a specific rubber friendly grease?
>
>
>>>If the seals in the hub are not designed to be used with
>>>hydrocarbon lubricants, your hub is toast. Who makes these things
>>>anyway? They seem to be shy and don't readily show up on a web
>>>search.
>
>
>>>>Don't use oil... it's too thin. My Laser Lite hub works fine with
>>>>bicycle-specific grease such as Finish Line or Park.
>
>
>>>In what way is oil "to thin?" As has been mentioned often, grease
>>>is oil in a "pudding" and has a viscosity that does not correlate
>>>to the grease stiffness. Your grease has an oil viscosity that
>>>defines its lubrication flow. That is also not directly related to
>>>film strength in boundary layer lubrication.
>
>
>>>So back to the question. What makes you sure that oil should not
>>>be used?
>
>
>>Ugh... all these big words. The oil won't keep water out as well as
>>grease will. Do I get a prize?
>
>
> No. If you visualize the grease as being static, as on a seatpost,
> where it is often used to prevent water intrusion, you are using the
> wrong model. The hub-to-axle joint rotates and "stirs" the grease and
> any water on its surface into an ice cream like paste. That is, the
> grease transports water into the hub if exposed to water. The oil in
> the grease emulsifies and in time can homogenize.
>
> To keep water out, either a double lipped seal with a drained central
> gap, or a labyrinth seal such as Sturmey-Archer hubs and many
> Ashtabula BB's have, is required. These drain water out the bottom by
> gravity, much as the eaves on a house do.
>
> |------
> | |----|
> |----| |
> | |
> | |
> ----| |----
>
> - - - - - - - - - - - How this prevents splash water intrusion should
> be apparent.
> ----| |----
> | |
> | |
> |----| |
> | |----|
> |------
>
> The gaps must be large enough not to act as capillaries, something
> that SunTour freewheels failed to do and are, therefore, not as
> weather proof as they were designed to be having half mm gap labyrinth
> seals that are visible as brass rings on the back side and hidden
> under the cone. It was a nice gesture though and works sort-of.
>
> http://www.sheldonbrown.com/brandt/sealed-bearings.html
>
> From your response, I take it you are guessing about which lubricants
> are effective and how. You might add that disclaimer before giving
> advice on lubrication.
>
> Jobst Brandt

why all the fud about sealed bearings jobst? how often have you had
seal failure on your car? how often have you had to repack its bearings?

reality check: sealed bearings are as good as the manufacturer wants
them to be. on bikes, a lot of seals really don't seal [as is evidenced
by being able to see light coming under a seal lip if you hold a such a
bearing with one seal up to the light], because customers bleat about
the bearings being too stiff. otoh, other manufacturers use sealed
bearings that /do/ seal, but people complain, e.g. mavic wheels. BUT,
these seals /do/ work, just like they do in your car. it's a spec
issue, not a fundamental problem, contrary to your poorly researched
opinion.