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FW-FM questions for the gurus

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  • henrysheil
    Hi all, I bought an alloy shell FM hub (1951) apparently in good condition. I m not a complete novice but no expert either. I did an internal inspection using
    Message 1 of 9 , Mar 16, 2011
      Hi all,

      I bought an alloy shell FM hub (1951) apparently in good condition. I'm not a complete novice but no expert either.
      I did an internal inspection using the parts diagrams and find that the K411 thrust washer is missing. It seems to me that the K530B clutch spring fits very nicely into the recessed profile of the K528A thrust ring as it is.
      So I'm at a loss to understand how a plain washer on the end of the spring would be of any benefit, except to compress the spring by stopping it fitting into the recess of the thrust ring. Any advice as to whether it's crucial?

      If it is, can someone give me the ID, OD and thickness of the thrust washer as I'll probably have to make it?

      Having built up the wheel and test ridden it, it seems very "draggy", is this normal? I have the cones set up to 1/4 turn back on the right and a tiny bit of play from the left one.

      It also shows a "false neutral" between the lowest gear and low, but still gives me the lowest when the cable is very taut. I can't find any mention of this anywhere, what could this mean?

      Any advice will be most gratefully received as I'm hoping to ride this in an event on Sunday.

      Henry
      Oz
    • Hilary Stone
      There are two types of thrust bearing for the end of the spring - the one with the recess does not need a washer. The other type of thrust bearing over the
      Message 2 of 9 , Mar 16, 2011
        There are two types of thrust bearing for the end of the spring - the
        one with the recess does not need a washer. The other type of thrust
        bearing over the axle key has a flat end and should be used with the
        thrust washer.

        There will always be some drag when freewheeling with SA hubs - the only
        ones where you need to consider are the ones with the compound planet
        pinions that need to be timed - KS, KSW, AM, FW, S5.

        Sturmey have neutrals between most gears; that is why it is advisable to
        use a proper trigger... and take care over the adjustment.

        Hilary Stone, Bristol, British Isles

        www.Hilarystone.com
        Period bicycle frames & parts






        On 16/03/2011 15:12, henrysheil wrote:
        > Hi all,
        >
        > I bought an alloy shell FM hub (1951) apparently in good condition. I'm
        > not a complete novice but no expert either.
        > I did an internal inspection using the parts diagrams and find that the
        > K411 thrust washer is missing. It seems to me that the K530B clutch
        > spring fits very nicely into the recessed profile of the K528A thrust
        > ring as it is.
        > So I'm at a loss to understand how a plain washer on the end of the
        > spring would be of any benefit, except to compress the spring by
        > stopping it fitting into the recess of the thrust ring. Any advice as to
        > whether it's crucial?
        >
        > If it is, can someone give me the ID, OD and thickness of the thrust
        > washer as I'll probably have to make it?
        >
        > Having built up the wheel and test ridden it, it seems very "draggy", is
        > this normal? I have the cones set up to 1/4 turn back on the right and a
        > tiny bit of play from the left one.
        >
        > It also shows a "false neutral" between the lowest gear and low, but
        > still gives me the lowest when the cable is very taut. I can't find any
        > mention of this anywhere, what could this mean?
        >
        > Any advice will be most gratefully received as I'm hoping to ride this
        > in an event on Sunday.
        >
        > Henry
        > Oz
        >
        >
      • henrysheil
        Many thanks Hilary, that s most useful. Back on it goes! Cheers Henry WA Oz
        Message 3 of 9 , Mar 17, 2011
          Many thanks Hilary, that's most useful. Back on it goes!

          Cheers
          Henry
          WA Oz

          --- In Geared_hub_bikes@yahoogroups.com, Hilary Stone <Hilary.stone@...> wrote:
          >
          > There are two types of thrust bearing for the end of the spring - the
          > one with the recess does not need a washer. The other type of thrust
          > bearing over the axle key has a flat end and should be used with the
          > thrust washer.
          >
          > There will always be some drag when freewheeling with SA hubs - the only
          > ones where you need to consider are the ones with the compound planet
          > pinions that need to be timed - KS, KSW, AM, FW, S5.
          >
          > Sturmey have neutrals between most gears; that is why it is advisable to
          > use a proper trigger... and take care over the adjustment.
          >
          > Hilary Stone, Bristol, British Isles
          >
          > www.Hilarystone.com
          > Period bicycle frames & parts
          >
          >
          >
          >
          >
          >
          > On 16/03/2011 15:12, henrysheil wrote:
          > > Hi all,
          > >
          > > I bought an alloy shell FM hub (1951) apparently in good condition. I'm
          > > not a complete novice but no expert either.
          > > I did an internal inspection using the parts diagrams and find that the
          > > K411 thrust washer is missing. It seems to me that the K530B clutch
          > > spring fits very nicely into the recessed profile of the K528A thrust
          > > ring as it is.
          > > So I'm at a loss to understand how a plain washer on the end of the
          > > spring would be of any benefit, except to compress the spring by
          > > stopping it fitting into the recess of the thrust ring. Any advice as to
          > > whether it's crucial?
          > >
          > > If it is, can someone give me the ID, OD and thickness of the thrust
          > > washer as I'll probably have to make it?
          > >
          > > Having built up the wheel and test ridden it, it seems very "draggy", is
          > > this normal? I have the cones set up to 1/4 turn back on the right and a
          > > tiny bit of play from the left one.
          > >
          > > It also shows a "false neutral" between the lowest gear and low, but
          > > still gives me the lowest when the cable is very taut. I can't find any
          > > mention of this anywhere, what could this mean?
          > >
          > > Any advice will be most gratefully received as I'm hoping to ride this
          > > in an event on Sunday.
          > >
          > > Henry
          > > Oz
          > >
          > >
          >
        • Mike Wilson
          I believe the S.A. manuals say 1/2 turn loose for the sprocket side cone, not 1/4. Michael Wilson
          Message 4 of 9 , Mar 17, 2011
            I believe the S.A. manuals say 1/2 turn loose for the sprocket side cone, not 1/4.

            Michael Wilson
          • Mark Stonich
            ... Yes. I always start with between 3/8 of a turn and 5/8ths. If the driver drags when the wheel is spun I back it out another 1/4 of a turn and re-adjust
            Message 5 of 9 , Mar 17, 2011
              > I believe the S.A. manuals say 1/2 turn loose for the sprocket side
              >cone, not 1/4.

              Yes.

              I always start with between 3/8 of a turn and 5/8ths. If the driver
              drags when the wheel is spun I back it out another 1/4 of a turn and
              re-adjust the left cone.

              I suppose it would be best to replace the HMW 147 Cone Lock Washer
              with a thin, flat washer so you can set it right at 1/2 turn instead
              of having to adjust in 90 degree increments.

              --

              Mark Stonich;
              BikeSmith Design & Fabrication
              5349 Elliot Ave S. Minneapolis, Minnesota 55417 USA
              Ph. (612) 824-2372 http://bikesmithdesign.com
            • Mike Wilson
              More thoughts: I used to set the sprocket-side cone at 3/8 turn and decided that was higher drag than 1/2 turn minimum. I believe the thrust washer was there
              Message 6 of 9 , Mar 17, 2011
                More thoughts:

                I used to set the sprocket-side cone at 3/8 turn and decided that was higher drag than 1/2 turn minimum.

                I believe the thrust washer was there to give lower friction between the spring and the driver - the cone end of the spring turns at a different rotational velocity than the driver end in all but direct drive. There are several variants of the assembly at the clutch end of the spring; I do not believe it is critical.

                I am just an amateur home-mechanic and owner/user of S.A. hubs. Hilary Stone probably has a lot more experience than I do.


                Michael Wilson
              • henrysheil
                Well I m very pleased with my 60 year old FM, I have it set up to give me 75, 67, 57 and 44 gear inches and I m using the top 3 a lot, I don t need anything
                Message 7 of 9 , Apr 2, 2011
                  Well I'm very pleased with my 60 year old FM, I have it set up to give me 75, 67, 57 and 44 gear inches and I'm using the top 3 a lot, I don't need anything higher on this bike (Moulton). After backing the RH cone out to 1/2 turn the dragginess is acceptable.

                  But the question now is, under load on a hill in the lowest 2 gears it "clicks" or "grinds" slightly inside somewhere, which I feel may be due to the RH cone not supporting the driver as well as it might. Is this likely to damage the internals, if so I'd rather put up with a little dragginess than damage such a lovely old item.

                  Advice and opinions please?

                  Henry
                  Oz


                  --- In Geared_hub_bikes@yahoogroups.com, Mike Wilson <mwilson@...> wrote:
                  >
                  > More thoughts:
                  >
                  > I used to set the sprocket-side cone at 3/8 turn and decided that was higher drag than 1/2 turn minimum.
                  >
                  > I believe the thrust washer was there to give lower friction between the spring and the driver - the cone end of the spring turns at a different rotational velocity than the driver end in all but direct drive. There are several variants of the assembly at the clutch end of the spring; I do not believe it is critical.
                  >
                  > I am just an amateur home-mechanic and owner/user of S.A. hubs. Hilary Stone probably has a lot more experience than I do.
                  >
                  >
                  > Michael Wilson
                  >
                • Joel
                  Hi Henry; With all English made SA hubs, (probably the new one s too, but I haven t a the chance to pull those apart yet), the position of the right hand cone
                  Message 8 of 9 , Apr 3, 2011
                    Hi Henry;

                    With all English made SA hubs, (probably the new one's too, but I
                    haven't a the chance to pull those apart yet), the position of the right
                    hand cone affects the alignment of the internals, you do this cone up
                    finger tight and back it off enough to get the locking washer seated on
                    its flats, 1/2 turn *maximum* (not 1/2 turn minimum as you've typed
                    below).

                    The adjustment of bearing preload should be done using the left hand
                    cone only. With all old SA you want to be able of feel the tiniest
                    amount of looseness at the rim but not at the axle.

                    Cheers

                    Joel


                    On Sun, 2011-04-03 at 03:12 +0000, henrysheil wrote:
                    > Well I'm very pleased with my 60 year old FM, I have it set up to give me 75, 67, 57 and 44 gear
                    > inches and I'm using the top 3 a lot, I don't need anything higher on this bike (Moulton).

                    > After backing the RH cone out to 1/2 turn the dragginess is acceptable.
                    >
                    > But the question now is, under load on a hill in the lowest 2 gears it
                    > "clicks" or "grinds" slightly inside somewhere, which I feel may be due
                    > to the RH cone not supporting the driver as well as it might.

                    > Is this likely to damage the internals, if so I'd rather put up with a
                    > little dragginess than damage such a lovely old item.
                    >
                    > Advice and opinions please?
                    >
                    > Henry
                    > Oz
                    >
                    >
                    > --- In Geared_hub_bikes@yahoogroups.com, Mike Wilson <mwilson@...> wrote:
                    > >
                    > > More thoughts:
                    > >
                    > > I used to set the sprocket-side cone at 3/8 turn and decided that was higher
                    > drag than 1/2 turn minimum.
                    > >
                    > > I believe the thrust washer was there to give lower friction between the spring
                    > and the driver - the cone end of the spring turns at a different rotational velocity
                    > than the driver end in all but direct drive. There are several variants of the assembly
                    > at the clutch end of the spring; I do not believe it is critical.
                    > >
                    > > I am just an amateur home-mechanic and owner/user of S.A. hubs. Hilary Stone probably has a lot more experience than I do.
                    > >
                    > >
                    > > Michael Wilson
                    > >
                    >
                    >
                    >
                    >
                    > ------------------------------------
                    >
                    > Yahoo! Groups Links
                    >
                    >
                    >
                  • Mike Wilson
                    Lowest 2 gears of the FM are using the low gear pawls which are on the left side. Noise probably not closely related to the right hand cone adjustment, but a
                    Message 9 of 9 , Apr 4, 2011
                      Lowest 2 gears of the FM are using the low gear pawls which are on the left side. Noise probably not closely related to the right hand cone adjustment, but a measurement is worth a thousand expert opinions.

                      I gave up on my FM hub because I broke the low gear pawl race off of several left ball cups. My guess is that I could have made it work if I had used a steel threaded hub shell from the 50s and used something as a shim support between the ball cup and the shell, but I did not think of that until many years later.

                      In the early 90s I converted to an S5 with 4th gear as level road; one of the dual pull-chain sculpted aluminum shell S5s that was unused but 10 or 15 years old. That worked really excellently - probably the most successful IGH bike/hub I have ever owned. Still works but not been in front-line service for about 8 years.


                      Michael Wilson
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