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Re: Sturmey Archer CS-RF3

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  • Rich W
    Gordon; On weight, I suspect that the figure you have for SRAM is with a cassette installed as the listed weight in the 2010 SRAM hubs tech manual is 970 grams
    Message 1 of 4 , Oct 6, 2011
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      Gordon;

      On weight, I suspect that the figure you have for SRAM is with a cassette installed as the listed weight in the 2010 SRAM hubs tech manual is 970 grams for the current aluminum shell versions. Over the years SRAM and Sachs have made multiple versions of this hub, some steel and some aluminum shelled.

      As for the SA warranty, I believe that all current SA hubs have the same 1 year warranty.

      Only the Shimano Alfine 8 and Rohloff hubs have the planet gears mounted on bearings that I know of. All other current hubs use bushings for the planet gears except possibly the Alfine 11. Historically SA only used bearings in this area for the first couple of years of their original 3 speed hub design. The switch to bushings was one of their first cost reduction changes to the original design.

      Rich Wood


      --- In Geared_hub_bikes@yahoogroups.com, "gordonKoppang" <gordonkoppang@...> wrote:
      >
      >
      > Does anyone have experience with Sunrace / Sturmey Archer's CS-RF3 hub?
      >
      > The claims made for the CS-RF3 seem too good to be true. The spec. sheet says it will tolerate an 11-34 cassette. There is claim posted on Bentrider (said to be from Sunrace USA rep David Prosser) that the CS-RF3 will tolerate a front chainring as small as 22t. A 22t granny driving a 34t sprocket on the cassette gets you to .647:1 running that through the low gear of the hub drops the final ratio to .485:1.
      >
      > http://www.bentrideronline.com/messageboard/showthread.php?t=67679&page=2
      >
      > The claimed weight for the CS-RF3 is 1090 grams. The only weight I could find for SRAM's DualDrive is 1444 grams. Since the CS-RF3 is both cheaper and lighter than the DualDrive, I wonder whether the planetary gears run on bushings or bearings. It's hard to imagine that the CS-RF3 is a high-efficiency hub. I could not find any information about warrantee coverage for the CS-RF3.
      >
      > Can anyone fill in the blanks?
      >
      > With thanks,
      >
      > Gordon Koppang
      >
    • pj
      I haven t seen an exploded diagram/parts list for the CS-RF3, but looking at the 3D computer models in the SA catalog, the internal design of the cassette hub
      Message 2 of 4 , Oct 7, 2011
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        I haven't seen an exploded diagram/parts list for the CS-RF3, but looking at the 3D computer models in the SA catalog, the internal design of the cassette hub is completely different from the design of the AW/SRF3.

        Rich W wrote in part:
        > Only the Shimano Alfine 8 and Rohloff hubs have
        > the planet gears mounted on bearings that I know
        > of.

        Really? I haven't read this about the Shimano 8 anywhere else, and Shimano only includes disassembly in their exploded diagram down to the "carrier unit". Do you have some reference you could share to the fact the Alfine 8 hub has roller or ball bearing mounted planets?

        This is as much as I was able to find on the Shimano 8 planet pinons:
        <http://youtu.be/BgWxFtAGU3U>

        > Historically SA only used bearings in this area for the
        > first couple of years of their original 3 speed hub design.
        > The switch to bushings was one of their first cost
        > reduction changes to the original design.

        I think they eliminated the rolling element bearings on the planets because they don't actually save a meaningful amount of friction/drag. Certainly the Kyle/Berto efficiency tests didn't find the T3 or AW hubs suffered from plain bearings on the planets.

        Gordon wrote in part:
        > It's hard to imagine that the CS-RF3 is a high-efficiency hub.

        Why is that? Other 3-speeds, when broken in and properly lubricated, have been shown to be remarkably efficient. What is it about the CS-RF3 that leads you to believe it will be otherwise?

        But BTW, thanks for the link to the thread. The claim allegedly from Sturmey that the "F30" hubs (CS-RF3, CS-RK3) are OK for tandems is interesting.

        The only user feedback I've seen on the CS-RF3 was on the mtbr forums. The poster claimed his CS-RF3 had begun slipping gears when standing-pedalling up hill. He allowed he'd been shifting the three-speed hub function with an indexed shifter other than the one Sturmey specifies must be used, but got testy when his error was pointed out and claimed he'd only ride Shimano from now on. Takes all kinds, I suppose.

        pj
      • Rich W
        PJ; It is shown and mentioned in the Shimano Tech Tips page titled Differences Between Hubs.pdf on page two. Here is the link. It actually states that the
        Message 3 of 4 , Oct 8, 2011
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          PJ;

          It is shown and mentioned in the Shimano Tech Tips page titled "Differences Between Hubs.pdf" on page two. Here is the link. It actually states that the shown difference is between the standard and premium Nexus hubs but I have also read that the roller bearings construction applies to the Alfine 8 too.

          This difference in construction has been discussed here in the past as I recall.

          http://bike.shimano.com/publish/content/global_cycle/en/us/index/tech_support/tech_tips.download.-Par50lparsys-0016-downloadFile.html/09)%20Differences%20Between%20Hubs.pdf

          or

          http://tinyurl.com/ya28lj8

          Rich Wood

          --- In Geared_hub_bikes@yahoogroups.com, "pj" <prester_john_in_cathay@...> wrote:
          >
          > I haven't seen an exploded diagram/parts list for the CS-RF3, but looking at the 3D computer models in the SA catalog, the internal design of the cassette hub is completely different from the design of the AW/SRF3.
          >
          > Rich W wrote in part:
          > > Only the Shimano Alfine 8 and Rohloff hubs have
          > > the planet gears mounted on bearings that I know
          > > of.
          >
          > Really? I haven't read this about the Shimano 8 anywhere else, and Shimano only includes disassembly in their exploded diagram down to the "carrier unit". Do you have some reference you could share to the fact the Alfine 8 hub has roller or ball bearing mounted planets?
          >
          > This is as much as I was able to find on the Shimano 8 planet pinons:
          > <http://youtu.be/BgWxFtAGU3U>
          >
          > > Historically SA only used bearings in this area for the
          > > first couple of years of their original 3 speed hub design.
          > > The switch to bushings was one of their first cost
          > > reduction changes to the original design.
          >
          > I think they eliminated the rolling element bearings on the planets because they don't actually save a meaningful amount of friction/drag. Certainly the Kyle/Berto efficiency tests didn't find the T3 or AW hubs suffered from plain bearings on the planets.
          >
          > Gordon wrote in part:
          > > It's hard to imagine that the CS-RF3 is a high-efficiency hub.
          >
          > Why is that? Other 3-speeds, when broken in and properly lubricated, have been shown to be remarkably efficient. What is it about the CS-RF3 that leads you to believe it will be otherwise?
          >
          > But BTW, thanks for the link to the thread. The claim allegedly from Sturmey that the "F30" hubs (CS-RF3, CS-RK3) are OK for tandems is interesting.
          >
          > The only user feedback I've seen on the CS-RF3 was on the mtbr forums. The poster claimed his CS-RF3 had begun slipping gears when standing-pedalling up hill. He allowed he'd been shifting the three-speed hub function with an indexed shifter other than the one Sturmey specifies must be used, but got testy when his error was pointed out and claimed he'd only ride Shimano from now on. Takes all kinds, I suppose.
          >
          > pj
          >
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