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Surly Dingle and IGH

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  • bennettmcqa
    First time poster... Has anyone had experience using the Surly Dingle (double-single) setup to extend the gearing of IGH? Running the numbers for the iM9 shows
    Message 1 of 5 , Jun 30, 2009
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      First time poster...
      Has anyone had experience using the Surly Dingle (double-single) setup to extend the gearing of IGH? Running the numbers for the iM9 shows its range can be extended from 340% to 465%, approaching the Rohloff's 526% at a fraction of the cost.
      Thanks for your input.

      Bennett
    • Rich Wood
      Bennett; Unfortunately the Surly Dingle is designed to mount on a threaded fixed gear hub that has provision for a threaded lock ring too. The lock ring is
      Message 2 of 5 , Jun 30, 2009
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        Bennett;

        Unfortunately the Surly Dingle is designed to mount on a threaded fixed gear hub that has provision for a threaded lock ring too. The lock ring is left hand threaded to keep the Dingle, or other rear fixed gear sprocket, from coming off when back pedalling a fixed gear bike.

        Almost all current gear hubs take a 3 splined sprocket held on with a large circlip. Mounting the Dingle on such a hub would require machining an adapter.

        All Shimano gear hubs, all except the iM9 SRAM hub and all SA hubs except the 8 speed and S3X use similar dimensioned interchangeable sprockets so such an adapter would work with most IGH hubs if made.

        The problem is that the threaded inner diameter of a FG sprocket and the inner diameter of the splined sprockets are about the same so an adapter would likely need to move the Dingle out considerably, causing interference problems with most frames and some IGH shifting mechanisms. The SRAM iM9 and SA 8 speed hubs use proprietary larger inner diameter sprockets than the inner diameter of the Dingle, making an adapter difficult.

        Years ago Cyclo did make 2 and 3 cog rear clusters that could be fitted to SA and Sachs hubs of the era. With careful machining and some welding a similar sprocket pair, using IGH sprockets, could probably be made today. Several members have the Cyclo sprocket clusters and are using them on SA gear hubs.

        The Dingle may work with the new SA S3x hub which is supposed to have provisions for a thread on freewheel. I am not sure if it could be locked on though as a reverse threaded lockring provision would also be needed to keep it from unscrewing I suspect. The S3x is going to be a 3 speed FG hub with no internal freewheel provision. As the S3x hub is not yet shipping no one can say for sure whether this will be practical or not.

        The Dingle, or a dual sprocket freewheel, might well work with the NuVinci hub as it is designed so an external thread-on freewheel provides the freewheeling action for the hub. People have reported using a FG sprocket with it as the hub does not allow reverse driving due to the internal design. Internal slippage gives a freewheeling effect with some drag on the pedals when not pedalling from what I have read.

        Rich Wood


        --- In Geared_hub_bikes@yahoogroups.com, "bennettmcqa" <bennettmca@...> wrote:
        >
        > First time poster...
        > Has anyone had experience using the Surly Dingle (double-single) setup to extend the gearing of IGH? Running the numbers for the iM9 shows its range can be extended from 340% to 465%, approaching the Rohloff's 526% at a fraction of the cost.
        > Thanks for your input.
        >
        > Bennett
        >
      • palatine_ej
        No reason you couldn t weld up a custom dingle for the iM9. Hadn t thought of it until now. What cog pair would give a nice half step set-up?
        Message 3 of 5 , Jun 30, 2009
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          No reason you couldn't weld up a custom dingle for the iM9. Hadn't thought of it until now. What cog pair would give a nice half step set-up?
        • Rich Wood
          palatine_ej; Most steps on the iM9 are about 14% with the end steps about 17% so a half step pair should have a difference of 7% to 8%. Very small steps. The
          Message 4 of 5 , Jun 30, 2009
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            palatine_ej;

            Most steps on the iM9 are about 14% with the end steps about 17% so a half step pair should have a difference of 7% to 8%. Very small steps. The factory sprockets are listed as 18T through 22T so a 18 and 19 would give about a 5.5% difference and a 18 and 20 would be close to 11%.

            I would think a pair at least 2 teeth different to provide a bailout low gear might be the way to go, or a pair chosen so the normally used one provides an adequate low and the secondary small sprocket provides a high speed downhill/tailwind option.

            Looking at my iM9 hub the clearance between the shifter cable connector tube and sprocket is fairly tight and iM9 sprockets are flat so it looks like there would probably be interference between the outer sprocket and the shifter connector tube.

            It might be easier to do a dual sprocket setup with a P5 or S7 as both have the hub shifting bits outside the dropouts on the frame. As they use industry standard sprockets a 2 speed Cyclo sprocket set might drop right on, or do so with minimal modifications.

            At the time Cyclo was making their accessory SA sprocket sets SA was making 3 and 4 speed hubs and per the Cyclo data sheet link in the Links area they would fit both hubs.

            Rich Wood


            --- In Geared_hub_bikes@yahoogroups.com, "palatine_ej" <danstrom@...> wrote:
            >
            > No reason you couldn't weld up a custom dingle for the iM9. Hadn't thought of it until now. What cog pair would give a nice half step set-up?
            >
          • Rich Wood
            BTW for those interested who have not seen it yet here is a link to the Cyclo data sheet on the SA Heritage web site.
            Message 5 of 5 , Jun 30, 2009
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              BTW for those interested who have not seen it yet here is a link to the Cyclo data sheet on the SA Heritage web site.

              http://www.sturmey-archerheritage.com/detail.php?id=316

              Rich Wood


              --- In Geared_hub_bikes@yahoogroups.com, "Rich Wood" <astronut1001@...> wrote:
              >
              > palatine_ej;
              >
              > Most steps on the iM9 are about 14% with the end steps about 17% so a half step pair should have a difference of 7% to 8%. Very small steps. The factory sprockets are listed as 18T through 22T so a 18 and 19 would give about a 5.5% difference and a 18 and 20 would be close to 11%.
              >
              > I would think a pair at least 2 teeth different to provide a bailout low gear might be the way to go, or a pair chosen so the normally used one provides an adequate low and the secondary small sprocket provides a high speed downhill/tailwind option.
              >
              > Looking at my iM9 hub the clearance between the shifter cable connector tube and sprocket is fairly tight and iM9 sprockets are flat so it looks like there would probably be interference between the outer sprocket and the shifter connector tube.
              >
              > It might be easier to do a dual sprocket setup with a P5 or S7 as both have the hub shifting bits outside the dropouts on the frame. As they use industry standard sprockets a 2 speed Cyclo sprocket set might drop right on, or do so with minimal modifications.
              >
              > At the time Cyclo was making their accessory SA sprocket sets SA was making 3 and 4 speed hubs and per the Cyclo data sheet link in the Links area they would fit both hubs.
              >
              > Rich Wood
              >
              >
              > --- In Geared_hub_bikes@yahoogroups.com, "palatine_ej" <danstrom@> wrote:
              > >
              > > No reason you couldn't weld up a custom dingle for the iM9. Hadn't thought of it until now. What cog pair would give a nice half step set-up?
              > >
              >
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