Sturmy Archer 8 speed

Discussion in 'Cycling Equipment' started by Dan Burkhart, Dec 6, 2005.

  1. Dan Burkhart

    Dan Burkhart New Member

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    I was just checking out the specs on this thing on the Sturmy Archer web site. Shimano and Sram will be playing catch up now with a disc brake version available. Interestingly, the lowest gear is direct drive, making the rest of the gears overdrive. I guess that means a tiny chain ring is in order.
    The overall range of ratios is similar to both the Nexus 8 and the Sram 7.
    I have several bikes on order for the spring with this hub, and one of them is earmarked for my wife's use. I'll let you all know how it works out.
    Dan
     
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  2. Werehatrack

    Werehatrack Guest

    On Wed, 7 Dec 2005 00:32:07 +1100, Dan Burkhart
    <Dan.Burkhart.1zmejz@no-mx.forums.cyclingforums.com> wrote:

    >
    >I was just checking out the specs on this thing on the Sturmy Archer web
    >site. Shimano and Sram will be playing catch up now


    You were, I take it, unaware that Sun borged Sturmey-Archer some time
    ago, then? Note the contact email address, info at sunrace dot com.
    --
    Typoes are a feature, not a bug.
    Some gardening required to reply via email.
    Words processed in a facility that contains nuts.
     
  3. Borged? A misleading representation of how Sun recycled Sturmey Archer
    from a dust bin after SA was neglected for many years and robbed by con
    artists. Sun has done for SA what SA needed for 75 years. Put money
    in to engineering new and improved designs.

    An all overdrive design may be more efficient or cheaper to produce.
    Anyhow I must rejoice that SA is born again and not another great
    company gone for good. I have 1 new AW 3 speed hub on a bike. It has
    a beautiful aluminum shell, sealed bearings and the dreaded neutral
    between 2 & 3rd is no more. Works perfectly.
     
  4. Rick Paulos writes:

    > Borged? A misleading representation of how Sun recycled Sturmey
    > Archer from a dust bin after SA was neglected for many years and
    > robbed by con artists. Sun has done for SA what SA needed for 75
    > years. Put money in to engineering new and improved designs.


    > An all overdrive design may be more efficient or cheaper to produce.
    > Anyhow I must rejoice that SA is born again and not another great
    > company gone for good. I have 1 new AW 3 speed hub on a bike. It
    > has a beautiful aluminum shell, sealed bearings and the dreaded
    > neutral between 2 & 3rd is no more. Works perfectly.


    Well, the sealed bearings aren't an improvement, judging from history.
    SA hubs had excellent non-contact labyrinth seals that worked so well
    that I have never found a hub from the 1950's that had any dirt or
    water intrusion. So that's a step backward. As to the, jumping out
    of top gear, I'm curious about what deign change was made to prevent
    this. I suspect it is only so because your unit is new.

    Have you taken it apart, and is it the same design as before, all held
    together using no screws or fasteners. If so, I would like to know
    what the "clutch" (driver cross) shape is that might prevent popping
    out of top gear under continuous high torque. This syndrome plagued
    early auto transmission until someone realized that through elasticity
    and shafts flex, gears tend to disengage in the absence of a positive
    retention design.

    Jobst Brandt
     
  5. On 07 Dec 2005 21:36:31 GMT, jobst.brandt@stanfordalumni.org wrote:

    >Well, the sealed bearings aren't an improvement, judging from history.
    >SA hubs had excellent non-contact labyrinth seals that worked so well
    >that I have never found a hub from the 1950's that had any dirt or
    >water intrusion. So that's a step backward. As to the, jumping out
    >of top gear, I'm curious about what deign change was made to prevent
    >this. I suspect it is only so because your unit is new.


    Sturmey's invented numerous ways to do without the blind spot over the
    years. Actually, the first units in the 18th century didn't have it, by
    using three sets of pawls, and it was introduced as a cost-cutting
    measure. One of the ingenious ways that would be virtually free I've seen
    a patent for involved slightly longer teeth on the ring wheel thingy with
    edges beveled, so that if the star clutch traveled right far enough to
    disengage from the planet wheel axles it would be forced back onto the
    planets, or similarly if it traveled left far enough to get out of second
    it'd be forced onto three.

    Also, better triggers & cables mean more positive engagement and fewer
    opportunities for the star clutch to wear in the first place.

    If you mean the diagonally worn star clutch climbing up from the planet
    wheel axle ends under force, I can think of a few ways to remedy that
    problem: 1) service the damn thing and replace the star clutch when it's
    done enough miles to be iffy (I always replace it and the pawls when I
    have one open anyway for other reasons -- usually the thread between the
    indicator rod and the little beam being gone) 2) make sure the shifter's
    appropriately adjusted at all times, and don't shift under power 3) make
    the ends of those axles about twice as long and/or the star clutch half as
    thick and edit cable pull appropriately. The problem only exists because
    the top of the star clutch teeth is even with or above (especially when
    adjusted too-tight) the ends of the axle ends. The most diagonally worn
    star clutch in the world won't climb up over axle ends that are a bit
    higher 4) give the planet wheel axle mounts a slot as key, so that they
    don't rotate (or put in the axles from the other side and just have tabs
    on the planet wheel housing), and file a reverse-diagonal slope onto them
    that acts toward positive engagement rather than against it.

    Anyway, as long as you're prepared to throw backwards compatibility for at
    least *some* of the bits out of the window it's entirely possible to do
    it.


    Jasper
     
  6. Jasper Janssen writes:

    >> Well, the sealed bearings aren't an improvement, judging from
    >> history. SA hubs had excellent non-contact labyrinth seals that
    >> worked so well that I have never found a hub from the 1950's that
    >> had any dirt or water intrusion. So that's a step backward. As to
    >> the, jumping out of top gear, I'm curious about what deign change
    >> was made to prevent this. I suspect it is only so because your
    >> unit is new.


    > Sturmey's invented numerous ways to do without the blind spot over
    > the years.


    I'm sorry, I don't understand what you mean by "blind spot" and what
    that has to do with the basic flaw in torque transmission in AW hubs.
    The design flaw is a basic misunderstanding of gear engagement in
    general.

    > Actually, the first units in the 18th century didn't have it, by
    > using three sets of pawls, and it was introduced as a cost-cutting
    > measure.


    I'm sorry, I think we are not on the same subject. The failure mode
    is one in which driving elements on the same but elastically bent
    shaft, push each other apart. This has nothing to do with ratchet
    pawls. The bending load comes from the chain pulling on a sprocket
    that lies between support bearings for that shaft.

    > One of the ingenious ways that would be virtually free I've seen a
    > patent for involved slightly longer teeth on the ring wheel thingy
    > with edges beveled, so that if the star clutch traveled right far
    > enough to disengage from the planet wheel axles it would be forced
    > back onto the planets, or similarly if it traveled left far enough
    > to get out of second it'd be forced onto three.


    That does not prevent the type of failure that causes the problem.
    Just making it so there is no undefined drive location cannot occur
    because otherwise it could be in two gears at once.

    > Also, better triggers & cables mean more positive engagement and
    > fewer opportunities for the star clutch to wear in the first place.


    That falls into the response that SA gave over the many years of these
    failures... "you mis-adjusted the shift linkage." That claim that was
    repeated endlessly over the years is false. Not only is it a
    misunderstanding of the failure mode but it defies the definition of a
    safe design, one that cannot throw you onto the street with a slight
    misadjustment.

    You'll notice that most of today's hub gears do not take the
    expedient means of entering the hub by using a chain through the axle.
    That in itself was asking for failure because that place is often
    banged against hard objects. Just think how many smashed shift chains
    bicycle shops replaced over the years. That was one of the most
    common failures and it was usually noticed by failure to shift
    correctly and to jump out of gear.

    > If you mean the diagonally worn star clutch climbing up from the planet
    > wheel axle ends under force, I can think of a few ways to remedy that
    > problem:


    > 1) service the damn thing and replace the star clutch when it's done
    > enough miles to be iffy (I always replace it and the pawls when I
    > have one open anyway for other reasons -- usually the thread between
    > the indicator rod and the little beam being gone)


    > 2) make sure the shifter is appropriately adjusted at all times, and
    > don't shift under power


    > 3) make the ends of those axles about twice as long and/or the star
    > clutch half as thick and edit cable pull appropriately. The problem
    > only exists because the top of the star clutch teeth is even with or
    > above (especially when adjusted too-tight) the ends of the axle
    > ends. The most diagonally worn star clutch in the world won't climb
    > up over axle ends that are a bit higher


    > 4) give the planet wheel axle mounts a slot as key, so that they
    > don't rotate (or put in the axles from the other side and just have
    > tabs on the planet wheel housing), and file a reverse-diagonal slope
    > onto them that acts toward positive engagement rather than against
    > it.


    You are not aware of the mechanism at work here or you wouldn't say
    all that... in true SA style. I rode these hubs to school for years
    and got all that good advice that you repeat practically from the SA
    bible. I used new driver crosses, new planet pins and went over the
    bars anyway in sprints on two occasions besides failures while seated.

    > Anyway, as long as you're prepared to throw backwards compatibility
    > for at least *some* of the bits out of the window it's entirely
    > possible to do it.


    It took me a while to be convinced that there are technical matters
    which manufacturers and their minions do not understand. I came
    across the same disengagement problem on some older motorcycle gear
    boxes. What occurred there was that the engine revved damn high when
    it jumped out under full throttle. That hurt less than falling from
    the bicycle.

    If the SA planet shafts had a slightly funnel shaped tip and the
    driver a matching slant, torque would force a more secure engagement
    rather than the driver weaseling its way out of engagement because its
    rotation axes was skewed a small fraction of a degree from the parts
    it was driving. This skew is elastic and is no longer present when
    the hub is disassembled to prove to the user that he is the culprit.

    Jobst Brandt
     
  7. rick-paulos@uiowa.edu wrote:
    > Borged? A misleading representation of how Sun recycled Sturmey Archer
    > from a dust bin after SA was neglected for many years and robbed by con
    > artists. Sun has done for SA what SA needed for 75 years. Put money
    > in to engineering new and improved designs.
    >
    > An all overdrive design may be more efficient or cheaper to produce.
    > Anyhow I must rejoice that SA is born again and not another great
    > company gone for good. I have 1 new AW 3 speed hub on a bike. It has
    > a beautiful aluminum shell, sealed bearings and the dreaded neutral
    > between 2 & 3rd is no more. Works perfectly.


    Funny, I was just re-reading Tony Hadland's page about S-A, then came
    over here to read this thread. The page shows how the 3-speed AW works
    (older version, anyway), and how the dreaded "no-drive" event happens.

    http://www.users.globalnet.co.uk/~hadland/elegy.htm

    Mark
     
  8. On 08 Dec 2005 02:27:26 GMT, jobst.brandt@stanfordalumni.org wrote:

    >You are not aware of the mechanism at work here


    Yes that's entirely possible so goddamn explain what the hell you're
    talking about instead of sniping ten times a post that I don't understand
    what you're saying. *breathe*

    What we have here is a failure to communicate, and in this particular
    case, it's you that's failing to communicate what you're talking about,
    not me that's failing to understand it.

    Jasper
     
  9. On 08 Dec 2005 02:27:26 GMT, jobst.brandt@stanfordalumni.org wrote:

    >> 4) give the planet wheel axle mounts a slot as key, so that they
    >> don't rotate (or put in the axles from the other side and just have
    >> tabs on the planet wheel housing), and file a reverse-diagonal slope
    >> onto them that acts toward positive engagement rather than against
    >> it.

    [...]
    >If the SA planet shafts had a slightly funnel shaped tip and the
    >driver a matching slant, torque would force a more secure engagement
    >rather than the driver weaseling its way out of engagement because its
    >rotation axes was skewed a small fraction of a degree from the parts


    That's exactly what I just suggested! How can I be misunderstanding what's
    happening so terribly if I come up with the same solutions as you?


    Jasper
     
  10. Jasper Janssen writes:

    >>> 4) give the planet wheel axle mounts a slot as key, so that they
    >>> don't rotate (or put in the axles from the other side and just have
    >>> tabs on the planet wheel housing), and file a reverse-diagonal slope
    >>> onto them that acts toward positive engagement rather than against
    >>> it.


    >> If the SA planet shafts had a slightly funnel shaped tip and the
    >> driver a matching slant, torque would force a more secure
    >> engagement rather than the driver weaseling its way out of
    >> engagement because its rotation axes was skewed a small fraction of
    >> a degree from the parts


    > That's exactly what I just suggested! How can I be misunderstanding
    > what's happening so terribly if I come up with the same solutions as
    > you?


    I didn't find that you suggested this in your numbered points that
    explain how to avoid forward freewheeling. Point 4.) above does not
    address that issue nor does the web site:

    http://www.users.globalnet.co.uk/~hadland/elegy.htm

    From that I have heard and read, the cause for disengagement under
    load is not understood. I've spent much time discussing this with
    people claiming to be SA experts and found that the concept of a
    skewed driver causing disengagement is not understood. I have not
    seen it mentioned in anyone's writing. Only that the shift mechanism
    was surely not adjusted correctly. Even with the shift "chain"
    removed, the driver (clutch) has only its engagement spring pressing
    it to the home position so there cannot be any misadjustment. In that
    condition these hubs also jump out of gear.

    Jobst Brandt
     
  11. This has happened to me, slipping in 3rd even with the indicator chain
    removed!

    I had things adjusted properly so the no-drive zone was avoided, and
    then found the hub slipping in third. I took the chain out to make sure
    it stayed in that gear, and sure enough it would spin as it should,
    slip once, then re-engage. This would happen at random, and always
    under more pressure. Not very confidence inspiring when trying to clear
    an intersection in a hurry...

    The hub stays in 2nd without issue - no slipping into the no-drive
    zone, but then into 3rd and it's a guessing game. I'm told this is due
    to wear on the inside of the hub's shell, so it's not just a matter of
    replacing the guts, but the whole hub, which means a wheel rebuild.
    Arghh...

    It's almost enough to make me rebuild it with a old Shimano 3-speed!
    (Too cheap to buy a new internal hub, and I like recycling whenever
    possible.) But everything I've read says those hubs can be problematic.
    Too bad, because they don't have the no-drive zone, and the shifter is
    easier to use (this is my winter bike, and of course I wear thick
    gloves). So I guess I'll install another AW and hope for the best. Or
    try the Shimano. Hmm...

    Ideally I would go single-speed or fixed for winter use, but being
    car-free I need to tow a trailer every now and then, and need a few
    extra gears.

    Mark
     
  12. Werehatrack

    Werehatrack Guest

    On 7 Dec 2005 13:08:19 -0800, "rick-paulos@uiowa.edu"
    <rick-paulos@uiowa.edu> wrote:

    >Borged? A misleading representation of how Sun recycled Sturmey Archer
    >from a dust bin after SA was neglected for many years and robbed by con
    >artists. Sun has done for SA what SA needed for 75 years. Put money
    >in to engineering new and improved designs.


    That's one view. The other is that Sun, having no rep in gearhubs,
    didn't think that their image as a supplier of second- and third-line
    components would give them any leverage in the gearhub market if they
    took the plunge on their own. But by assimilating the corpse of SA
    and acquiring its name in the process, they could cherry-pick what
    could be reproduced of the SA line to gain immediate entry as a
    gearhub supplier with kit that was known if not universally loved.
    I'm sure that their plan was to bank on SA's name recognition to make
    it easier to get their own designs into the market once the legacy
    products had paved the way. All that's left of the old SA is the name
    and a few bits that will likely get cast off as Sun gets its own hubs
    out. We can only hope that they will avoid duplicating (or adding to)
    the errors made in SA's history.

    >An all overdrive design may be more efficient or cheaper to produce.
    >Anyhow I must rejoice that SA is born again and not another great
    >company gone for good. I have 1 new AW 3 speed hub on a bike. It has
    >a beautiful aluminum shell, sealed bearings and the dreaded neutral
    >between 2 & 3rd is no more. Works perfectly.


    --
    Typoes are a feature, not a bug.
    Some gardening required to reply via email.
    Words processed in a facility that contains nuts.
     
  13. jobst.brandt@stanfordalumni.org wrote:
    >
    > If the SA planet shafts had a slightly funnel shaped tip and the
    > driver a matching slant, torque would force a more secure engagement
    > rather than the driver weaseling its way out of engagement because its
    > rotation axes was skewed a small fraction of a degree from the parts
    > it was driving.


    Is this the kind of thing that could be done by a person with a Dremel
    tool? It doesn't sound like it would have to be super-accurate.

    - Frank Krygowski
     
  14. Mark who? writes:

    > This has happened to me, slipping in 3rd even with the indicator
    > chain removed!


    > I had things adjusted properly so the no-drive zone was avoided, and
    > then found the hub slipping in third. I took the chain out to make
    > sure it stayed in that gear, and sure enough it would spin as it
    > should, slip once, then re-engage. This would happen at random, and
    > always under more pressure. Not very confidence inspiring when
    > trying to clear an intersection in a hurry...


    > The hub stays in 2nd without issue - no slipping into the no-drive
    > zone, but then into 3rd and it's a guessing game. I'm told this is
    > due to wear on the inside of the hub's shell, so it's not just a
    > matter of replacing the guts, but the whole hub, which means a wheel
    > rebuild. Arghh...


    Not true. It is the interface between the driver cross (clutch) and
    the planet pins. As I said, even new ones will pop out of engagement.
    There is no way for the hub to disengage in low and middle gear.

    > It's almost enough to make me rebuild it with a old Shimano 3-speed!
    > (Too cheap to buy a new internal hub, and I like recycling whenever
    > possible.) But everything I've read says those hubs can be
    > problematic. Too bad, because they don't have the no-drive zone,
    > and the shifter is easier to use (this is my winter bike, and of
    > course I wear thick gloves). So I guess I'll install another AW and
    > hope for the best. Or try the Shimano. Hmm...


    I've never gone back to hub gears after my experience with SA so I
    never took a Shimano hub apart to see how they solved the problem...
    if in fact they did so.

    > Ideally I would go single-speed or fixed for winter use, but being
    > car-free I need to tow a trailer every now and then, and need a few
    > extra gears.


    I'm satisfied with a derailleur.

    Jobst Brandt
     
  15. Frank Krygowski writes:

    >> If the SA planet shafts had a slightly funnel shaped tip and the
    >> driver a matching slant, torque would force a more secure
    >> engagement rather than the driver weaseling its way out of
    >> engagement because its rotation axes was skewed a small fraction of
    >> a degree from the parts it was driving.


    > Is this the kind of thing that could be done by a person with a
    > Dremel tool? It doesn't sound like it would have to be
    > super-accurate.


    No. Two reasons are that the pins are case hardened and would need to
    be modified on a lathe (possibly by grinding) and the driver cross
    would take some careful mill machining to make all four faces exactly
    located and slanted (ever so slightly).

    Jobst Brandt
     
  16. On 08 Dec 2005 07:13:52 GMT, jobst.brandt@stanfordalumni.org wrote:

    First off, I'd like to apologise for my previous postings. I wasn't
    thinking very clearly, seeing as how '8 am' and 'late at night' as opposed
    to 'early in the morning' are really not things that should go together.

    >From that I have heard and read, the cause for disengagement under
    >load is not understood. I've spent much time discussing this with
    >people claiming to be SA experts and found that the concept of a
    >skewed driver causing disengagement is not understood. I have not
    >seen it mentioned in anyone's writing. Only that the shift mechanism
    >was surely not adjusted correctly. Even with the shift "chain"
    >removed, the driver (clutch) has only its engagement spring pressing
    >it to the home position so there cannot be any misadjustment. In that
    >condition these hubs also jump out of gear.


    Well, the mechanism that's generally suggested (and what I was riffing
    off) is that from inevitable wear due to slight misadjustments and various
    other things, the star clutch teeth wear until they are, at least to a
    certain extent, not straight edged but diagonal (in the direction that
    would tend to force them off the planet wheels). I've seen pictures of a
    star clutch whose teeth were worn at probably a 20 or more degree angle,
    though I never saw one of those in the flesh.

    I suppose it's possible that under extreme pedaling loads, the axle flexes
    in such a way so as to cause the clutch to ride up (incidentally, wouldn't
    strengthening the engagement spring cause the problem to move to high
    enough loads that it would no longer be a problem?). Regardless of whether
    theory one or two is the culprit, design changes that fix one should
    pretty much also fix the other. Making the notches (Planet axle ends) that
    the clutch engages with higher relative to the driver and/or giving a
    positive engagement bevel to star clutch and/or notches should work, no?



    Incidentally, returning to the problem of the no-drive gap between 2 and
    3. If you make the second gear notches extend farther left, without
    changing anything else, and give them an angle at the end, it would be
    possible for the star clutch to momentarily be in between gears 2 and 3
    and engaging them both, but wouldn't the faster-turning 2nd gear notches
    immediately press the star clutch down into the third gear engagement,
    thus removing the lock-up situation? Given that you're supposed to shift
    with the pedals stationary and that if you do that the entire innards are
    standing still, I think you might even be able to shift back into 2.


    Jasper
     
  17. Jasper Janssen writes:

    >> From that I have heard and read, the cause for disengagement under
    >> load is not understood. I've spent much time discussing this with
    >> people claiming to be SA experts and found that the concept of a
    >> skewed driver causing disengagement is not understood. I have not
    >> seen it mentioned in anyone's writing. Only that the shift
    >> mechanism was surely not adjusted correctly. Even with the shift
    >> "chain" removed, the driver (clutch) has only its engagement spring
    >> pressing it to the home position so there cannot be any
    >> misadjustment. In that condition these hubs also jump out of gear.


    > Well, the mechanism that's generally suggested (and what I was
    > riffing off) is that from inevitable wear due to slight
    > misadjustments and various other things, the star clutch teeth wear
    > until they are, at least to a certain extent, not straight edged but
    > diagonal (in the direction that would tend to force them off the
    > planet wheels). I've seen pictures of a star clutch whose teeth
    > were worn at probably a 20 or more degree angle, though I never saw
    > one of those in the flesh.


    I wouldn't call the "teeth" and as you can see this is a cross with
    flat faces that drive against round pins, which already presents a
    contact problem in itself. These pins are not a press fit in
    their housing so they already have the ability to skew with respect to
    the hub axis to which they are theoretically parallel.

    http://www.users.globalnet.co.uk/~hadland/sa/saaw.pdf

    Part 510 Planet pin is driven by part 505A Sliding clutch which is
    driven by K462, on which the drive sprocket is mounted.

    > I suppose it's possible that under extreme pedaling loads, the axle flexes
    > in such a way so as to cause the clutch to ride up (incidentally, wouldn't
    > strengthening the engagement spring cause the problem to move to high
    > enough loads that it would no longer be a problem?).


    Disengagement forces are large enough to overcome any reasonable spring
    load but only if torque is continuous to prevent allowing the designed
    spring from re-engaging the clutch to its home position. As it turns
    out, an athletic pedaler is able to do this and that is where the
    failure occurred most reliably... with brand new parts.

    > Regardless of whether theory one or two is the culprit, design
    > changes that fix one should pretty much also fix the other. Making
    > the notches (Planet axle ends) that the clutch engages with higher
    > relative to the driver and/or giving a positive engagement bevel to
    > star clutch and/or notches should work, no?


    Notches will not do because that would make exiting that gear position
    impractically difficult. As I said, a slight taper to the contact
    faces would have done it but then driving round pins against a flat
    surface also does not guarantee durability. As you suggest, the
    clutches of used hubs have wear marks at these contacts, some of which
    are rounded from having disengaged under load. That is the only way a
    rounded ramp (exit) can be generated. Just that alone should have
    kicked the hubris out of the SA engineers sails, but it didn't. They
    were so sure of the correctness of their design that they attributed
    the failures to faulty user adjustment of the shift chain.

    > Incidentally, returning to the problem of the no-drive gap between 2
    > and 3. If you make the second gear notches extend farther left,
    > without changing anything else, and give them an angle at the end,
    > it would be possible for the star clutch to momentarily be in
    > between gears 2 and 3 and engaging them both, but wouldn't the
    > faster-turning 2nd gear notches immediately press the star clutch
    > down into the third gear engagement, thus removing the lock-up
    > situation? Given that you're supposed to shift with the pedals
    > stationary and that if you do that the entire innards are standing
    > still, I think you might even be able to shift back into 2.


    Not possible in this mechanism. The 5-speed hub was better in this
    respect, not trying to drive the ends of planet pins. Just the same,
    amazingly many parts are the same for both the 3 and 5-speed hubs
    especially the housing.

    Jobst Brandt
     
  18. Thakjs for the clarification as to why mine slips in 3rd. I replaced
    the clutch twice, and when that didn't solve the problem I got pissed
    off enough to yank the innards and replaced them from another hub. Of
    course, those had wear as well...

    I'd be happy with a derailer as well, but where I live (Ottawa, Canada)
    the winter temps are a mite brisk (I've cycled at -25C). Derailers tend
    to get gunked up with slush, and sometimes freeze in place, as do the
    hub's pawls (they stick so that you get freewheeling in both directions
    - not fun).

    I've never had the AW hub not shift in the cold, and never had the
    pawls stick either. I guess I have three choices: either try one more
    clutch and pin replacement, try the Shimano hub, or finally give in and
    buy a new model. I have access to lots of the old hubs (I volunteer at
    our local bike recycling place), so it comes down to spending time or
    spending money...

    Mark
     
  19. Tim McNamara

    Tim McNamara Guest

    Werehatrack <rault00@earthWEEDSlink.net> writes:

    > On 7 Dec 2005 13:08:19 -0800, "rick-paulos@uiowa.edu"
    > <rick-paulos@uiowa.edu> wrote:
    >
    >>Borged? A misleading representation of how Sun recycled Sturmey
    >>Archer from a dust bin after SA was neglected for many years and
    >>robbed by con artists. Sun has done for SA what SA needed for 75
    >>years. Put money in to engineering new and improved designs.

    >
    > That's one view. The other is that Sun, having no rep in gearhubs,
    > didn't think that their image as a supplier of second- and
    > third-line components would give them any leverage in the gearhub
    > market if they took the plunge on their own. But by assimilating
    > the corpse of SA and acquiring its name in the process, they could
    > cherry-pick what could be reproduced of the SA line to gain
    > immediate entry as a gearhub supplier with kit that was known if not
    > universally loved.


    Well, you had your Cynic-Os for breakfast. They not only bought the
    name, they bought the tooling and hired some of the staff according to
    news reports at the time. And so what if your version is accurate?
    It's a product in some demand, serves a useful purpose, and should be
    carried on.

    > I'm sure that their plan was to bank on SA's name recognition to
    > make it easier to get their own designs into the market once the
    > legacy products had paved the way. All that's left of the old SA is
    > the name and a few bits that will likely get cast off as Sun gets
    > its own hubs out. We can only hope that they will avoid duplicating
    > (or adding to) the errors made in SA's history.


    By reputation they have fixed the neutral gear problem by replacing
    the old clutch mechanism with a ball-locking mechanism in the S-A 3
    speed. That's a good thing; S-A resisted this simple fix for decades,
    preferring to blame the user. IIUC they replaced the steel hub body
    with an aluminum alloy body, also a nice touch. And Sun-SA have
    pursued new products and potentially new markets. And, for those of
    us still with freewheels, they remain one of the few makers on the
    planet to bother with making freewheels.
     
  20. A Muzi

    A Muzi Guest

    mark@drumbent.com wrote:

    > This has happened to me, slipping in 3rd even with the indicator chain
    > removed!
    >
    > I had things adjusted properly so the no-drive zone was avoided, and
    > then found the hub slipping in third. I took the chain out to make sure
    > it stayed in that gear, and sure enough it would spin as it should,
    > slip once, then re-engage. This would happen at random, and always
    > under more pressure. Not very confidence inspiring when trying to clear
    > an intersection in a hurry...
    >
    > The hub stays in 2nd without issue - no slipping into the no-drive
    > zone, but then into 3rd and it's a guessing game. I'm told this is due
    > to wear on the inside of the hub's shell, so it's not just a matter of
    > replacing the guts, but the whole hub, which means a wheel rebuild.
    > Arghh...
    >
    > It's almost enough to make me rebuild it with a old Shimano 3-speed!
    > (Too cheap to buy a new internal hub, and I like recycling whenever
    > possible.) But everything I've read says those hubs can be problematic.
    > Too bad, because they don't have the no-drive zone, and the shifter is
    > easier to use (this is my winter bike, and of course I wear thick
    > gloves). So I guess I'll install another AW and hope for the best. Or
    > try the Shimano. Hmm...
    >
    > Ideally I would go single-speed or fixed for winter use, but being
    > car-free I need to tow a trailer every now and then, and need a few
    > extra gears.


    Although Jobst had a less than positive experience I've
    never had that happen in a literal lifetime of commuting on
    Sturmey hubs. Not once.

    I am still unclear about the syndrome.

    Let's rule out any worn bits such as the clutch and pins (
    pedaling while shifting can chip the edges). And Jobst
    agrees the easily-kinked control wire is not at fault here.

    Jobst says a generally sloppy fit and axle deflection can
    allow the driver and clutch to move - where? Not much room
    inside!

    A Shimano is smaller and the parts fit more closely so I
    suppose that's an alternate. Jim Adney's opinion of Shimano
    hubs is that if they saw any care or lubrication they might
    have worked. Since 'better' bikes all had Sturmey in the
    day, Shimano hubs on XMart bikes were poorly adjusted and
    seldom lubricated. My own opinion is not as generous.

    [I haven't talked with Jim about this in a good long while.
    He may have further thoughts]

    You were told, "this is due to wear on the inside of the
    hub's shell". Since the high and direct gears are driven
    through the same pawl/ratchet set so that can't be true.

    I can accept that there is something wrong in there (no more
    credible observer than Mr Brandt) but I still don't get it
    and this is the third iteration in as many years.
    --
    Andrew Muzi
    www.yellowjersey.org
    Open every day since 1 April, 1971
     
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