Swapping internals in S-A hub?

Discussion in 'Cycling Equipment' started by dabac, May 22, 2008.

  1. dabac

    dabac Well-Known Member

    Joined:
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    Hi guys,

    Are S-A hub shells identical across the range?

    Aided by this forum I've been toying with various ideas on how to improve the usefulness of a composite wheel with a 3-speed hub.
    And although I now have a a fairly good idea on how to get a slightly wider range and a few more intermediate gears by going to a triple front with carefully calculated tooth counts I still haven't got the range I'll need for a comfortable commute, using my current mtb-based ride as a reference.

    So, is there some other option I should consider before I try to graft a Shimano-compatible DS hub flange onto the composite wheel by some cruel and unusual method?

    For instance, would it be possible to transplant the internals from a S-A 5 speed into the hub shell of a 3-speed?
     
    Tags:


  2. Jenny Brien

    Jenny Brien Guest

    On Thu, 22 May 2008 12:34:12 +0100, dabac
    <[email protected]> wrote:

    >
    > Hi guys,
    >
    > Are S-A hub shells identical across the range?
    >
    > Aided by this forum I've been toying with various ideas on how to
    > improve the usefulness of a composite wheel with a 3-speed hub.
    > And although I now have a a fairly good idea on how to get a slightly
    > wider range and a few more intermediate gears by going to a triple front
    > with carefully calculated tooth counts I still haven't got the range
    > I'll need for a comfortable commute, using my current mtb-based ride as
    > a reference.
    >
    > So, is there some other option I should consider before I try to graft
    > a Shimano-compatible DS hub flange onto the composite wheel by some
    > cruel and unusual method?
    >
    > For instance, would it be possible to transplant the internals from a
    > S-A 5 speed into the hub shell of a 3-speed?
    >
    >

    Yes, I've done it
     
  3. dabac

    dabac Well-Known Member

    Joined:
    Sep 16, 2003
    Messages:
    2,289
    Likes Received:
    139
    Good news! Now let's see what ebay has to offer...
     
  4. someone wrote:

    > Aided by this forum I've been toying with various ideas on how to
    > improve the usefulness of a composite wheel with a 3-speed hub. And
    > although I now have a a fairly good idea on how to get a slightly
    > wider range and a few more intermediate gears by going to a triple
    > front with carefully calculated tooth counts I still haven't got the
    > range I'll need for a comfortable commute, using my current
    > MTB-based ride as a reference.


    > So, is there some other option I should consider before I try to
    > graft a Shimano-compatible DS hub flange onto the composite wheel by
    > some cruel and unusual method?


    > For instance, would it be possible to transplant the internals from
    > a S-A 5 speed into the hub shell of a 3-speed?


    They are identical and the 5-speed is less likely to pop into neutral
    when sprinting.

    Jobst Brandt
     
  5. Tim McNamara

    Tim McNamara Guest

    In article <[email protected]>,
    dabac <[email protected]> wrote:

    > Hi guys,
    >
    > Are S-A hub shells identical across the range?
    >
    > Aided by this forum I've been toying with various ideas on how to
    > improve the usefulness of a composite wheel with a 3-speed hub. And
    > although I now have a a fairly good idea on how to get a slightly
    > wider range and a few more intermediate gears by going to a triple
    > front with carefully calculated tooth counts I still haven't got the
    > range I'll need for a comfortable commute, using my current mtb-based
    > ride as a reference.
    >
    > So, is there some other option I should consider before I try to
    > graft a Shimano-compatible DS hub flange onto the composite wheel by
    > some cruel and unusual method?
    >
    > For instance, would it be possible to transplant the internals from a
    > S-A 5 speed into the hub shell of a 3-speed?


    Yes, at least with the older made-in-Britain ones. Mark Stonich in
    Minneapolis has done this mod several times. It's a straight swap.
     
  6. On May 22, 6:58 pm, Tim McNamara <[email protected]> wrote:
    > In article <[email protected]>,
    >
    > > For instance, would it be possible to transplant the internals from a
    > > S-A 5 speed into the hub shell of a 3-speed?

    >
    > Yes, at least with the older made-in-Britain ones. Mark Stonich in
    > Minneapolis has done this mod several times. It's a straight swap.


    I thought I read that the lowest gear of old S-A five speeds was
    extremely inefficient. IOW, that shifting to low didn't really reduce
    your workload significantly, but just gave you less speed.

    I rode a friend's S-A five speed a few times, and got the impression
    that the tale was true.

    - Frank Krygowski
     
  7. Frank Krygowski <[email protected]> wrote:

    >>> For instance, would it be possible to transplant the internals
    >>> from a S-A 5 speed into the hub shell of a 3-speed?


    >> Yes, at least with the older made-in-Britain ones. Mark Stonich in
    >> Minneapolis has done this mod several times. It's a straight swap.


    > I thought I read that the lowest gear of old S-A five speeds was
    > extremely inefficient. IOW, that shifting to low didn't really
    > reduce your workload significantly, but just gave you less speed.


    > I rode a friend's S-A five speed a few times, and got the impression
    > that the tale was true.


    So after riding up a few hundred yards of hill, was the hub noticeably
    warm? My son's SA S5 has ordinary planetary gears that have no more
    friction that other gears. Low gear is achieved through the stepped
    planets that have a different number of teeth for input and output.
    That's all that's different.

    Jobst Brandt
     
  8. On Thu, 22 May 2008 20:03:35 -0700 (PDT), Frank Krygowski
    <[email protected]> wrote:

    >I thought I read that the lowest gear of old S-A five speeds was
    >extremely inefficient. IOW, that shifting to low didn't really reduce
    >your workload significantly, but just gave you less speed.
    >
    >I rode a friend's S-A five speed a few times, and got the impression
    >that the tale was true.
    >
    >- Frank Krygowski


    Dear Frank,

    Whatever the truth may be, this is a good example of the familiar RBT
    controversy:

    A poster heard about some effect, rode a bicycle, and things felt that
    way--so was the effect real, or was it just expectation?

    I couldn't find any efficiency testing of a 5-speed Sturmey-Archer,
    but even a detailed test might not have settled the question.

    After all, what if first gear was shown to be, say, 5.3% less
    efficient than second gear? Is that increased work-load actually
    noticeable while grinding up a hill at a 9.7% lower speed with [insert
    imaginary number here] less wind drag?

    The familiar Kyle & Berto efficiency study doesn't suggest that first
    gear in hub drives is a hidden boat anchor:
    http://www.ihpva.org/pubs/HP52.pdf

    Sometimes that pdf downloads, sometimes it doesn't. It's worth saving
    the damned file for later reference. Here's the table that compares
    the efficiency, gear-by-gear, of some hub-drives at 80, 150, and 200
    watts:

    1 2 3 4 5 6 7 8 9 10 11 12 13 14
    Maker/Speeds
    Power Efficiency Percent**
    Sachs 3 80 95.0 92.9 93.6
    150 94.2 95.6 94.8
    200 94.1 94.9 94.1
    Shimano 3 80 90.5 93.5 87.2
    150 93.0 93.9 88.6
    200 93.2 95.0 87.2
    Sturmey 3 80 92.3 95.4 91.8
    150 93.3 95.3 91.8
    200 93.0 95.6 91.8
    Shimano 4 80 93.6 90.1 87.1 85.8
    Automatic 150 95.6 90.9 88.9 87.0
    200 95.3 92.8 90.0 88.0
    Sachs 7 80 88.7 — — 89.2
    150 89.9 — — 92.3
    200* 91.0* — — 93.0*
    Shimano 7 80 90.8 90.7 87.4 89.0 83.6 90.9 88.2
    150 91.8 92.9 89.9 89.0 85.6 92.8 90.4
    200 92.8 94.5 90.3 91.8 86.4 93.7 91.4
    Sturmey 7 80 87.3 88.7 88.4 93.0 89.3 86.0 83.0
    150 89.1 89.0 91.1 93.3 90.4 88.5 85.4
    200 89.7 90.3 91.3 94.7 91.0 88.6 85.3
    Rohloff 14 80 89.1 90.3 87.8 90.3 87.5 87.8 86.1 89.7 90.8 87.7 89.7
    87.1 87.8 86.1
    150 90.6 92.5 89.9 92.2 89.6 91.0 89.9 92.6 92.7 90.4 92.3
    90.4 89.7 89.1
    200 91.3 92.5 90.9 93.4 90.5 90.9 90.2 92.8 92.7 91.1 93.5
    90.0 91.1 90.4

    *The shift mechanism was broken, and would shift to only two gears.

    ** All efficiencies are uncorrected for the power consumed by the
    ergometer wheel drive. Although this is not large, it would increase
    the indicated efficiencies by 2 to 2.5% in most cases.

    ------------

    Here's how 1st gear efficiency compares to 2nd gear from that table:

    Sachs 3 +2.1% to -1.4%
    Shimano 3 -0.3% to -0.9%
    Shim auto 4 -2.5% to -5.7%
    Sachs 7 (broken, no data)
    Shimano 7 +0.1% to -1.7%
    Sturmey 7 +0.1% to -1.4%
    Rohloff 14 -1.2% to -1.9%

    So a typical hub-drive first gear loses less than 2% of power compared
    to second gear. That's less than the drag from a light generator.

    Some riders might claim that they can detect such <2% losses (<4 watts
    at 200 watts) even when they shift from one gear to another, but such
    sensitivity would be impressive.

    But Kyle & Berto didn't test the 5-speed Sturmey-Archer. Maybe that
    hub has some design quirk that makes its first gear a real dog, unlike
    the 3, 4, 7, and 14 speed hubs.

    Cheers,

    Carl Fogel
     
  9. A Muzi

    A Muzi Guest

    > Frank Krygowski <[email protected]> wrote:
    >> I thought I read that the lowest gear of old S-A five speeds was
    >> extremely inefficient. IOW, that shifting to low didn't really reduce
    >> your workload significantly, but just gave you less speed.
    >> I rode a friend's S-A five speed a few times, and got the impression
    >> that the tale was true.


    [email protected] wrote:
    > Whatever the truth may be, this is a good example of the familiar RBT
    > controversy:
    >
    > A poster heard about some effect, rode a bicycle, and things felt that
    > way--so was the effect real, or was it just expectation?
    >
    > I couldn't find any efficiency testing of a 5-speed Sturmey-Archer,
    > but even a detailed test might not have settled the question.
    >
    > After all, what if first gear was shown to be, say, 5.3% less
    > efficient than second gear? Is that increased work-load actually
    > noticeable while grinding up a hill at a 9.7% lower speed with [insert
    > imaginary number here] less wind drag?
    >
    > The familiar Kyle & Berto efficiency study doesn't suggest that first
    > gear in hub drives is a hidden boat anchor:
    > http://www.ihpva.org/pubs/HP52.pdf
    >
    > Sometimes that pdf downloads, sometimes it doesn't. It's worth saving
    > the damned file for later reference. Here's the table that compares
    > the efficiency, gear-by-gear, of some hub-drives at 80, 150, and 200
    > watts:
    >
    > 1 2 3 4 5 6 7 8 9 10 11 12 13 14
    > Maker/Speeds
    > Power Efficiency Percent**
    > Sachs 3 80 95.0 92.9 93.6
    > 150 94.2 95.6 94.8
    > 200 94.1 94.9 94.1
    > Shimano 3 80 90.5 93.5 87.2
    > 150 93.0 93.9 88.6
    > 200 93.2 95.0 87.2
    > Sturmey 3 80 92.3 95.4 91.8
    > 150 93.3 95.3 91.8
    > 200 93.0 95.6 91.8
    > Shimano 4 80 93.6 90.1 87.1 85.8
    > Automatic 150 95.6 90.9 88.9 87.0
    > 200 95.3 92.8 90.0 88.0
    > Sachs 7 80 88.7 — — 89.2
    > 150 89.9 — — 92.3
    > 200* 91.0* — — 93.0*
    > Shimano 7 80 90.8 90.7 87.4 89.0 83.6 90.9 88.2
    > 150 91.8 92.9 89.9 89.0 85.6 92.8 90.4
    > 200 92.8 94.5 90.3 91.8 86.4 93.7 91.4
    > Sturmey 7 80 87.3 88.7 88.4 93.0 89.3 86.0 83.0
    > 150 89.1 89.0 91.1 93.3 90.4 88.5 85.4
    > 200 89.7 90.3 91.3 94.7 91.0 88.6 85.3
    > Rohloff 14 80 89.1 90.3 87.8 90.3 87.5 87.8 86.1 89.7 90.8 87.7 89.7
    > 87.1 87.8 86.1
    > 150 90.6 92.5 89.9 92.2 89.6 91.0 89.9 92.6 92.7 90.4 92.3
    > 90.4 89.7 89.1
    > 200 91.3 92.5 90.9 93.4 90.5 90.9 90.2 92.8 92.7 91.1 93.5
    > 90.0 91.1 90.4
    >
    > *The shift mechanism was broken, and would shift to only two gears.
    >
    > ** All efficiencies are uncorrected for the power consumed by the
    > ergometer wheel drive. Although this is not large, it would increase
    > the indicated efficiencies by 2 to 2.5% in most cases.
    >
    > ------------
    >
    > Here's how 1st gear efficiency compares to 2nd gear from that table:
    >
    > Sachs 3 +2.1% to -1.4%
    > Shimano 3 -0.3% to -0.9%
    > Shim auto 4 -2.5% to -5.7%
    > Sachs 7 (broken, no data)
    > Shimano 7 +0.1% to -1.7%
    > Sturmey 7 +0.1% to -1.4%
    > Rohloff 14 -1.2% to -1.9%
    >
    > So a typical hub-drive first gear loses less than 2% of power compared
    > to second gear. That's less than the drag from a light generator.
    >
    > Some riders might claim that they can detect such <2% losses (<4 watts
    > at 200 watts) even when they shift from one gear to another, but such
    > sensitivity would be impressive.
    >
    > But Kyle & Berto didn't test the 5-speed Sturmey-Archer. Maybe that
    > hub has some design quirk that makes its first gear a real dog, unlike
    > the 3, 4, 7, and 14 speed hubs.


    Efficiency, or lack thereof, is not at all obvious riding, at least to me.
    (I switch semi-annually between an AW and a fixed gear. Same rims/tires.
    Neither feels any more or less efficient. But then to Carl's comment,
    my fixie has a tire driven dynamo. The other has a GH6 DynoHub.)

    With Sturmey's S-5, gearing begins with AW's +33% high, direct, - 25%
    low then adds an additional +10% 'super high' and -10% 'super low'. Ten
    percent being a smallish difference, a rider who expects salvation with
    a 'bail out' gear when clicking from 2 to 1 may be disappointed. And as
    we know disappointment can lead to misdirected blame, "it's not efficient!".

    --
    Andrew Muzi
    <www.yellowjersey.org/>
    Open every day since 1 April, 1971
    ** Posted from http://www.teranews.com **
     
  10. jim beam

    jim beam Guest

    [email protected] wrote:
    > On Thu, 22 May 2008 20:03:35 -0700 (PDT), Frank Krygowski
    > <[email protected]> wrote:
    >
    >> I thought I read that the lowest gear of old S-A five speeds was
    >> extremely inefficient. IOW, that shifting to low didn't really reduce
    >> your workload significantly, but just gave you less speed.
    >>
    >> I rode a friend's S-A five speed a few times, and got the impression
    >> that the tale was true.
    >>
    >> - Frank Krygowski

    >
    > Dear Frank,
    >
    > Whatever the truth may be, this is a good example of the familiar RBT
    > controversy:
    >
    > A poster heard about some effect, rode a bicycle, and things felt that
    > way--so was the effect real, or was it just expectation?


    nah, i noticed this stuff when i was a kid too small to sit the seat of
    my mother's s.a. 3-speed bike. my derailleured dad's bike, i could ride
    with one leg through the frame so i had comparison. nobody then was
    telling me about planetary gear boxes. certainly not my mother.



    >
    > I couldn't find any efficiency testing of a 5-speed Sturmey-Archer,
    > but even a detailed test might not have settled the question.
    >
    > After all, what if first gear was shown to be, say, 5.3% less
    > efficient than second gear? Is that increased work-load actually
    > noticeable while grinding up a hill at a 9.7% lower speed with [insert
    > imaginary number here] less wind drag?
    >
    > The familiar Kyle & Berto efficiency study doesn't suggest that first
    > gear in hub drives is a hidden boat anchor:
    > http://www.ihpva.org/pubs/HP52.pdf
    >
    > Sometimes that pdf downloads, sometimes it doesn't. It's worth saving
    > the damned file for later reference. Here's the table that compares
    > the efficiency, gear-by-gear, of some hub-drives at 80, 150, and 200
    > watts:
    >
    > 1 2 3 4 5 6 7 8 9 10 11 12 13 14
    > Maker/Speeds
    > Power Efficiency Percent**
    > Sachs 3 80 95.0 92.9 93.6
    > 150 94.2 95.6 94.8
    > 200 94.1 94.9 94.1
    > Shimano 3 80 90.5 93.5 87.2
    > 150 93.0 93.9 88.6
    > 200 93.2 95.0 87.2
    > Sturmey 3 80 92.3 95.4 91.8
    > 150 93.3 95.3 91.8
    > 200 93.0 95.6 91.8
    > Shimano 4 80 93.6 90.1 87.1 85.8
    > Automatic 150 95.6 90.9 88.9 87.0
    > 200 95.3 92.8 90.0 88.0
    > Sachs 7 80 88.7 � � 89.2
    > 150 89.9 � � 92.3
    > 200* 91.0* � � 93.0*
    > Shimano 7 80 90.8 90.7 87.4 89.0 83.6 90.9 88.2
    > 150 91.8 92.9 89.9 89.0 85.6 92.8 90.4
    > 200 92.8 94.5 90.3 91.8 86.4 93.7 91.4
    > Sturmey 7 80 87.3 88.7 88.4 93.0 89.3 86.0 83.0
    > 150 89.1 89.0 91.1 93.3 90.4 88.5 85.4
    > 200 89.7 90.3 91.3 94.7 91.0 88.6 85.3
    > Rohloff 14 80 89.1 90.3 87.8 90.3 87.5 87.8 86.1 89.7 90.8 87.7 89.7
    > 87.1 87.8 86.1
    > 150 90.6 92.5 89.9 92.2 89.6 91.0 89.9 92.6 92.7 90.4 92.3
    > 90.4 89.7 89.1
    > 200 91.3 92.5 90.9 93.4 90.5 90.9 90.2 92.8 92.7 91.1 93.5
    > 90.0 91.1 90.4
    >
    > *The shift mechanism was broken, and would shift to only two gears.
    >
    > ** All efficiencies are uncorrected for the power consumed by the
    > ergometer wheel drive. Although this is not large, it would increase
    > the indicated efficiencies by 2 to 2.5% in most cases.
    >
    > ------------
    >
    > Here's how 1st gear efficiency compares to 2nd gear from that table:
    >
    > Sachs 3 +2.1% to -1.4%
    > Shimano 3 -0.3% to -0.9%
    > Shim auto 4 -2.5% to -5.7%
    > Sachs 7 (broken, no data)
    > Shimano 7 +0.1% to -1.7%
    > Sturmey 7 +0.1% to -1.4%
    > Rohloff 14 -1.2% to -1.9%
    >
    > So a typical hub-drive first gear loses less than 2% of power compared
    > to second gear. That's less than the drag from a light generator.


    it's not about gear to gear, it's about overall efficiencies in the
    80's. that's not good. and below 200W, hub hears really do show
    noticeably lower power than chain gears.


    >
    > Some riders might claim that they can detect such <2% losses (<4 watts
    > at 200 watts) even when they shift from one gear to another, but such
    > sensitivity would be impressive.


    what's even more "impressive" is people standing in line to claim they
    /can't/ tell when they haven't even done any physical comparison! could
    they paradoxically be the same people claiming detectable difference in
    tire rolling resistance?


    >
    > But Kyle & Berto didn't test the 5-speed Sturmey-Archer. Maybe that
    > hub has some design quirk that makes its first gear a real dog, unlike
    > the 3, 4, 7, and 14 speed hubs.
    >
    > Cheers,
    >
    > Carl Fogel
     
  11. On Fri, 23 May 2008 12:35:36 -0700, jim beam
    <[email protected]> wrote:

    [snip]

    >it's not about gear to gear, it's about overall efficiencies in the
    >80's.


    [snip]

    Dear Jim,

    Frank wrote about how dropping from second to first in a 5-speed
    Sturmey-Archer seemed to reveal a dramatic difference in efficiency.

    He might be right, he might have been expecting the difference after
    hearing about it somewhere, or he might have been expecting a bigger
    jump than the 10% change, as Andrew Muzi points out elsewhere in this
    thread.

    In any case, this sub-thread is specifically about gear-to-gear
    efficiency differences in the same hub.

    Cheers,

    Carl Fogel
     
  12. On May 23, 4:34 pm, [email protected] wrote:
    >
    >
    > Frank wrote about how dropping from second to first in a 5-speed
    > Sturmey-Archer seemed to reveal a dramatic difference in efficiency.


    Well, what I really felt was "Wow. That downshift didn't seem to help
    much at all. I'm working just as hard even though I'm climbing
    slower."

    The situation: Bike was an ancient ladies frame Dunelt, owned by a
    widow friend. It had been her husbands. (He'd had a much larger rear
    cog brazed onto the original.)

    We were visiting on vacation, and I was attempting to give the bike a
    little tuneup for her. Their town, in the Appalachian foothills,
    featured lots of short steep climbs (hence the big rear cog). She'd
    warned me that her husband had some trouble keeping the hub gear
    properly adjusted, and it demonstrated some trouble with a false
    neutral. I fussed with cable adjustment and improved things, but
    never got it to shift perfectly.

    I've reassembled S-A three speeds, but never a five speed. I'm not
    familiar enough with the guts to know if some bad component in there
    could generate both shifting problems and extra inefficiency in low
    gear.

    This was long ago (probably 15 years), so my memory isn't to be
    trusted; but IIRC, I read about the inefficient low _after_ my
    experience with that bike, so it was a case of the reading confirming
    my impression, not vice-versa.

    - Frank Krygowski
     
  13. On Fri, 23 May 2008 17:29:48 -0700 (PDT), Frank Krygowski
    <[email protected]> wrote:

    >On May 23, 4:34 pm, [email protected] wrote:
    >>
    >>
    >> Frank wrote about how dropping from second to first in a 5-speed
    >> Sturmey-Archer seemed to reveal a dramatic difference in efficiency.

    >
    >Well, what I really felt was "Wow. That downshift didn't seem to help
    >much at all. I'm working just as hard even though I'm climbing
    >slower."
    >
    >The situation: Bike was an ancient ladies frame Dunelt, owned by a
    >widow friend. It had been her husbands. (He'd had a much larger rear
    >cog brazed onto the original.)
    >
    >We were visiting on vacation, and I was attempting to give the bike a
    >little tuneup for her. Their town, in the Appalachian foothills,
    >featured lots of short steep climbs (hence the big rear cog). She'd
    >warned me that her husband had some trouble keeping the hub gear
    >properly adjusted, and it demonstrated some trouble with a false
    >neutral. I fussed with cable adjustment and improved things, but
    >never got it to shift perfectly.
    >
    >I've reassembled S-A three speeds, but never a five speed. I'm not
    >familiar enough with the guts to know if some bad component in there
    >could generate both shifting problems and extra inefficiency in low
    >gear.
    >
    >This was long ago (probably 15 years), so my memory isn't to be
    >trusted; but IIRC, I read about the inefficient low _after_ my
    >experience with that bike, so it was a case of the reading confirming
    >my impression, not vice-versa.
    >
    >- Frank Krygowski


    Dear Frank,

    I kept looking and found these extended comments, which support and
    explain your impression of 1st gear in a 5-speed Sturmey-Archer being
    less efficient than 2nd gear. The actual claim from S-A is a drop from
    93% to 89%, but that might mean as much as 93.4% to 88.5%.

    Just to confuse things, there were two versions of the 5-speed S-A
    hub.

    ***

    David Henshaw, Oct 98:

    The 5-speed Sturmey is less efficient than the 3-speed in gears 1 and
    5. Try riding up the same hill on a 3-speed in gear 1 and a 5-speed in
    gear 1. The lower gearing on the 5 gives no real advantage. I was
    sceptical until Andrew Ritchie, the man himself, demonstrated this.
    Now I believe it. And the 5 is very adjustment-sensitive, unlike the
    3, which lasts forever and ever.

    On a 5-speed, I'd go for a 14-tooth sprocket, which gives about 8%
    lower gearing. But, please remember to change the shim pack - the 14T
    is thicker than the 13T... The 12% optional lower gearing is certainly
    worth fitting on the 5-speed if you want really low gearing, but I'm
    not sure about the 18% - a front changer is probably a more sensible
    option.

    I'm still happiest with a light, efficient 3-speed with standard
    gearing. My clunky old bike still holds the unofficial Brompton speed
    record, set at CycleFest 1996 by Richard Grigsby.

    ***

    Willi Mindak, Nov 98:

    I received an e- mail today from Marketing at SA. This was in reply to
    an e- mail I send over a month ago. It says:

    Dear Sir

    The only information I have on this type relates to the 5 speed hub,
    the information is as follows:-

    Efficiency

    Gear Ratios Efficiency
    Super Low 0.667 89%
    Low 0.789 93%
    Normal 1.00 96%
    High 1.266 94%
    Super High 1.5 88%

    Efficiency Test Conditions

    Motor Torque Arm balance weight = 2.2Kg
    Motor Speed = 64 RPM
    No. of chainwheel teeth = 46
    No. of Sprocket teeth = 18

    I hope this information assists you.
    Yours faithfully
    Trevor Wilkinson
    Marketing Executive

    No surprises here. Legend had it that 1st and 5th gear were a bit
    harder to work. Third gear is best with no internal ratio; I take it
    the 4% are just bearing/ chain losses. I also asked for the 3 speed
    values, but no joy. Anyway, these values are in the expected range.
    They are actually better than I thought.

    ***

    Why is highest and lowest gear in a 5 speed less efficient than
    highest and lowest in a 3 speed?

    Stein Somers, Oct 1998:

    My guess: in the extremer gears, the planets in the cage roll on a
    bigger central fixed cog, hence they are smaller in diameter and make
    more rounds per minute. Both factors increase the friction at their
    (simple) bearings. Maybe on top more than three planets are needed to
    cope with the driving forces because the teeth on a smaller planet
    make less firm contact with the central cog.

    Come to think of it, the basic planetary system can only reach a 2:1
    drive ratio using infinitely small planets. That's a 400% gear ratio,
    low to high gear. (SA-3 has 178%, SA-5 has 225%). So how does the
    illustrious Rohloff hub obtain more than 500%??

    Carsten Thies, Jan 2003:

    It has two identical planetary gears in line, giving 7 gears*, plus an
    additional step-down planetary gear for the lower 7 gears.
    * it's not 3x3=9 gears because step-up step-down or vice versa would
    give the same as direct gear.
    Custfold, Oct 1998:

    The reason for the extreme high/extreme low being accessed by pulling
    the second lever should give a clue - the old SA5 system used a second
    cable to pull the dog over on the LHS of the unit and engage a step-up
    ratio in the drive chain - otherwise the middle 3 were direct into the
    gear cage. This in turn means a bigger slot in the axle and extra
    little piece to slide in it for all 5 speed hubs. The Sprinter merely
    uses a longer pull stroke to operate a 2-stage little bit in a slot
    from 1 cable.

    ***

    Everything above is from:
    http://stein.dommel.be/brompton/chapters/Gears.html#HubGearEfficiency

    Cheers,

    Carl Fogel
     
  14. A Muzi

    A Muzi Guest

    >> [email protected] wrote:
    >>> Frank wrote about how dropping from second to first in a 5-speed
    >>> Sturmey-Archer seemed to reveal a dramatic difference in efficiency.


    > Frank Krygowski <[email protected]> wrote:
    >> Well, what I really felt was "Wow. That downshift didn't seem to help
    >> much at all. I'm working just as hard even though I'm climbing
    >> slower."
    >>
    >> The situation: Bike was an ancient ladies frame Dunelt, owned by a
    >> widow friend. It had been her husbands. (He'd had a much larger rear
    >> cog brazed onto the original.)
    >>
    >> We were visiting on vacation, and I was attempting to give the bike a
    >> little tuneup for her. Their town, in the Appalachian foothills,
    >> featured lots of short steep climbs (hence the big rear cog). She'd
    >> warned me that her husband had some trouble keeping the hub gear
    >> properly adjusted, and it demonstrated some trouble with a false
    >> neutral. I fussed with cable adjustment and improved things, but
    >> never got it to shift perfectly.
    >>
    >> I've reassembled S-A three speeds, but never a five speed. I'm not
    >> familiar enough with the guts to know if some bad component in there
    >> could generate both shifting problems and extra inefficiency in low
    >> gear.
    >>
    >> This was long ago (probably 15 years), so my memory isn't to be
    >> trusted; but IIRC, I read about the inefficient low _after_ my
    >> experience with that bike, so it was a case of the reading confirming
    >> my impression, not vice-versa.


    [email protected] wrote:
    > I kept looking and found these extended comments, which support and
    > explain your impression of 1st gear in a 5-speed Sturmey-Archer being
    > less efficient than 2nd gear. The actual claim from S-A is a drop from
    > 93% to 89%, but that might mean as much as 93.4% to 88.5%.
    >
    > Just to confuse things, there were two versions of the 5-speed S-A
    > hub.
    >
    > ***
    >
    > David Henshaw, Oct 98:
    >
    > The 5-speed Sturmey is less efficient than the 3-speed in gears 1 and
    > 5. Try riding up the same hill on a 3-speed in gear 1 and a 5-speed in
    > gear 1. The lower gearing on the 5 gives no real advantage. I was
    > sceptical until Andrew Ritchie, the man himself, demonstrated this.
    > Now I believe it. And the 5 is very adjustment-sensitive, unlike the
    > 3, which lasts forever and ever.
    >
    > On a 5-speed, I'd go for a 14-tooth sprocket, which gives about 8%
    > lower gearing. But, please remember to change the shim pack - the 14T
    > is thicker than the 13T... The 12% optional lower gearing is certainly
    > worth fitting on the 5-speed if you want really low gearing, but I'm
    > not sure about the 18% - a front changer is probably a more sensible
    > option.
    >
    > I'm still happiest with a light, efficient 3-speed with standard
    > gearing. My clunky old bike still holds the unofficial Brompton speed
    > record, set at CycleFest 1996 by Richard Grigsby.
    >
    > ***
    >
    > Willi Mindak, Nov 98:
    >
    > I received an e- mail today from Marketing at SA. This was in reply to
    > an e- mail I send over a month ago. It says:
    >
    > Dear Sir
    >
    > The only information I have on this type relates to the 5 speed hub,
    > the information is as follows:-
    >
    > Efficiency
    >
    > Gear Ratios Efficiency
    > Super Low 0.667 89%
    > Low 0.789 93%
    > Normal 1.00 96%
    > High 1.266 94%
    > Super High 1.5 88%
    >
    > Efficiency Test Conditions
    >
    > Motor Torque Arm balance weight = 2.2Kg
    > Motor Speed = 64 RPM
    > No. of chainwheel teeth = 46
    > No. of Sprocket teeth = 18
    >
    > I hope this information assists you.
    > Yours faithfully
    > Trevor Wilkinson
    > Marketing Executive
    >
    > No surprises here. Legend had it that 1st and 5th gear were a bit
    > harder to work. Third gear is best with no internal ratio; I take it
    > the 4% are just bearing/ chain losses. I also asked for the 3 speed
    > values, but no joy. Anyway, these values are in the expected range.
    > They are actually better than I thought.
    >
    > ***
    >
    > Why is highest and lowest gear in a 5 speed less efficient than
    > highest and lowest in a 3 speed?
    >
    > Stein Somers, Oct 1998:
    >
    > My guess: in the extremer gears, the planets in the cage roll on a
    > bigger central fixed cog, hence they are smaller in diameter and make
    > more rounds per minute. Both factors increase the friction at their
    > (simple) bearings. Maybe on top more than three planets are needed to
    > cope with the driving forces because the teeth on a smaller planet
    > make less firm contact with the central cog.
    >
    > Come to think of it, the basic planetary system can only reach a 2:1
    > drive ratio using infinitely small planets. That's a 400% gear ratio,
    > low to high gear. (SA-3 has 178%, SA-5 has 225%). So how does the
    > illustrious Rohloff hub obtain more than 500%??
    >
    > Carsten Thies, Jan 2003:
    >
    > It has two identical planetary gears in line, giving 7 gears*, plus an
    > additional step-down planetary gear for the lower 7 gears.
    > * it's not 3x3=9 gears because step-up step-down or vice versa would
    > give the same as direct gear.
    > Custfold, Oct 1998:
    >
    > The reason for the extreme high/extreme low being accessed by pulling
    > the second lever should give a clue - the old SA5 system used a second
    > cable to pull the dog over on the LHS of the unit and engage a step-up
    > ratio in the drive chain - otherwise the middle 3 were direct into the
    > gear cage. This in turn means a bigger slot in the axle and extra
    > little piece to slide in it for all 5 speed hubs. The Sprinter merely
    > uses a longer pull stroke to operate a 2-stage little bit in a slot
    > from 1 cable.
    >
    > ***
    >
    > Everything above is from:
    > http://stein.dommel.be/brompton/chapters/Gears.html#HubGearEfficiency


    From Somers above "Maybe on top more than three planets are needed "

    S5 and AW each have four planet gears (Brit: pinions), not three.

    p.s. SW have three, but SW of course 'Seldom Work';AWs 'Always Work'!

    p.p.s Yes I know it's 'Type A, Wide Range' but the mnemonic is cute.
    --
    Andrew Muzi
    <www.yellowjersey.org/>
    Open every day since 1 April, 1971
    ** Posted from http://www.teranews.com **
     
  15. "A Muzi" <[email protected]> a écrit:

    > With Sturmey's S-5, gearing begins with AW's +33% high,
    > direct, - 25% low then adds an additional +10% 'super high'
    > and -10% 'super low'. Ten percent being a smallish difference,
    > a rider who expects salvation with a 'bail out' gear when clicking
    > from 2 to 1 may be disappointed.


    It's a bit more than 10% (the middle three gears are spaced a touch narrower
    than an AW). The two ratios are 15:19 (19:15) and 2:3 (3:2). That gives (as
    a percentage of direct drive):

    66.7 78.9 100 126.6 150

    James Thomson
     
  16. Tim McNamara

    Tim McNamara Guest

    In article <[email protected]>,
    A Muzi <[email protected]> wrote:

    > From Somers above "Maybe on top more than three planets are needed "
    >
    > S5 and AW each have four planet gears (Brit: pinions), not three.


    My Sachs Torpedo 3 speed hub has, as far as I have found out from
    searching on the net, 3 planet gears and that hub has a reputation for
    reliability that is better than the AW (no walking out of engagement in
    high gear). It also rated a bit higher in efficiency in Frank Berto's
    tests- perhaps due to having three rather than four planet gears?

    > p.s. SW have three, but SW of course 'Seldom Work';AWs 'Always Work'!
    >
    > p.p.s Yes I know it's 'Type A, Wide Range' but the mnemonic is cute.


    Well, perhaps "'Twill Always Work Right" would fit. :)
     
  17. On May 24, 1:59 am, "James Thomson" <[email protected]> wrote:
    > "Frank Krygowski" <[email protected]> a écrit:
    >
    > > I thought I read that the lowest gear of old S-A five speeds
    > > was extremely inefficient. IOW, that shifting to low didn't
    > > really reduce your workload significantly, but just gave you
    > > less speed.

    >
    > That's an old myth. There's some relevant discussion in this thread:
    >
    > http://groups.google.fr/group/rec.bicycles.tech/browse_thread/thread/...
    >
    > James Thomson


    Hmm. Not much meaningful discussion, though, from what I can see.
    Just two people disagreeing, with no relevant data.

    It would be nice to see some test data on the S-A 5 speed.

    - Frank Krygowski
     
  18. Tim McNamara

    Tim McNamara Guest

    In article
    <[email protected]m>,
    Frank Krygowski <[email protected]> wrote:

    > On May 24, 1:59 am, "James Thomson" <[email protected]> wrote:
    > > "Frank Krygowski" <[email protected]> a écrit:
    > >
    > > > I thought I read that the lowest gear of old S-A five speeds was
    > > > extremely inefficient. IOW, that shifting to low didn't really
    > > > reduce your workload significantly, but just gave you less speed.

    > >
    > > That's an old myth. There's some relevant discussion in this
    > > thread:
    > >
    > > http://groups.google.fr/group/rec.bicycles.tech/browse_thread/thread
    > > /...
    > >
    > > James Thomson

    >
    > Hmm. Not much meaningful discussion, though, from what I can see.
    > Just two people disagreeing, with no relevant data.
    >
    > It would be nice to see some test data on the S-A 5 speed.


    In case your news server missed it, someone posted information they got
    from S-A about the efficiencies of the S-A 5 speed in the various gears.
    There was a pretty big drop in efficiency in gears 1 and 5. It should
    just a few posts back up the thread.
     
  19. Dan Burkhart

    Dan Burkhart New Member

    Joined:
    Nov 27, 2003
    Messages:
    333
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    0
    Modern incarnations have triple planet sets, not quads. I'm looking at the internals of a current production 5 speed right now.
    Dan Burkhart
    www.boomerbicycle.ca
     
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