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How does the Schlumpf hub work?

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  • #16
    Originally posted by MuniOrBust View Post
    Also, is it possible to have a reduction gear using a planetary gear set?
    Yes, in fact most three speed hubs have a reduction gear as it is simply the inverse of the higher gear. In high gear, the sun gear is the input (cranks) and the ring gear is the output (hub) if you switched the bindings around so that the cranks turned the ring gear and the hub was turned by the sun gear than you would have a lower than 1:1 gearing.

    Originally posted by MuniOrBust View Post
    This wiki page seems to suggest it:
    If I understand the description correctly this is an specific variation on the planetary gearing system which while ingenious probably only works for very low gear ratios and has an inherent backlash which would only get worse as one increased the ratios.

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    • #17
      Originally posted by napalm View Post
      Super G- To change gears on the Schlumpf hub the rider hits the shifting button with his/her ankle on the down-stroke of their pedal revolution.
      Ouch! I'm no expert at shifting, but I use the side of the heel of my shoe, not my ankle.

      Judging by the images above, it looks like possibly this shifts the "drive cog" over to the flat-toothed gear and away from the planetary gears to give you the 1:1 gear. Something like that?
      John Foss
      www.unicycling.com

      "Who is going to argue with a mom who can ride a unicycle?" -- Forums member "HiMo"

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      • #18
        Originally posted by johnfoss View Post
        Ouch! I'm no expert at shifting, but I use the side of the heel of my shoe, not my ankle.

        Judging by the images above, it looks like possibly this shifts the "drive cog" over to the flat-toothed gear and away from the planetary gears to give you the 1:1 gear. Something like that?
        I do not want to get into a "heels or ankles" discussion, but I started with using the heels, until I recently found out that it is easier to shift with the padding of the shoe which is just below the ankle.
        Marcus | youtube | municycle.com
        I ride for fun

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        • #19
          Originally posted by justtysen View Post
          Yes, in fact most three speed hubs have a reduction gear as it is simply the inverse of the higher gear. In high gear, the sun gear is the input (cranks) and the ring gear is the output (hub) if you switched the bindings around so that the cranks turned the ring gear and the hub was turned by the sun gear than you would have a lower than 1:1 gearing.

          That's way more complicated than it needs to be, you really just need to make the gears on surrounding the main gear larger, and make the main gear smaller. that way all you're changing is the diameter, not the construction of the entire hub assembly.
          Steel is real! => I ride a Nimbus!

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          • #20
            darkoman drive system solves all problems, put it on an 09 torker and you have what you all are looking for!!

            a unicycle hub has to be simpler than a bicycle hub w/ the same amount of gears considering that neither can really slip either direction w/ the exception of a ratchet system for the chain cog on a bicycle.
            ><> Unicycle For Christ <><
            MY VIDEOS
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            • #21
              Nice animation of all 3 planetary configurations here.
              http://science.howstuffworks.com/gear7.htm

              Then scroll down one page.
              Last edited by curbrider; 2010-01-22, 08:35 AM. Reason: WILL link direct to item
              Mark

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              • #22
                [ame="http://www.youtube.com/watch?v=SQ-oxRSMlGg"]YouTube- Geared[/ame]

                This unicycle was build by some one in germany.
                It's not mine.
                I have riden it at the unicon 14.
                The gear ratio is a lot higher than a schlumpf hub.

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                • #23
                  Originally posted by skrobo View Post
                  darkoman drive system solves all problems, put it on an 09 torker and you have what you all are looking for!!
                  What is "darkoman drive system"? My searches came up empty as far as drive systems are concerned.

                  --> Grease for your Schlumpf hub (free shipping!) <--

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                  • #24
                    Originally posted by rvs View Post
                    YouTube- Geared

                    This unicycle was build by some one in germany.
                    It's not mine.
                    I have riden it at the unicon 14.
                    The gear ratio is a lot higher than a schlumpf hub.
                    That must be jogi's 1:2.5 ratio unicycle. Unfortunately it was broken some months ago, and it was a fixed ratio (no gear shifting)
                    Last edited by hugo; 2010-01-22, 01:19 PM.
                    Marcus | youtube | municycle.com
                    I ride for fun

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                    • #25
                      Originally posted by naturequack View Post
                      You want pictures? Here are all of the pictures that I've been able to collect over the last couple of years:
                      I was going to add to this thread to say that I have some pretty decent photos of the hub internals... but those photos (well, top 4 anyway) are mine. Oh well.

                      Just to comment on the freewheeling aspect of a gear change; there is a short moment when the wheel rotates independently of the hub. Theoretically, this is for a maximum of 1/12th of a revolution, and often much shorter, although a couple of times I swear it has gone on longer. You don't need to freewheel for very long at all for it to feel like a lifetime though!

                      STM

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                      • #26
                        Why do all of you disassemble your hubs? Just for curiosity and for taking some photos? Or is there are real business case behind?
                        Don't get me wrong, I really appreciate that pictures. But I would never ever take my hub apart, just so see what it looks like from interior.
                        Are you aware that disassembling the hub kills warranty?
                        Wolfgang

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                        • #27
                          I do not think that people really disassembled their hubs. Some photos look like they came from Florian - but I may be wrong.
                          Marcus | youtube | municycle.com
                          I ride for fun

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                          • #28
                            Florian had a set of hub internals at Ride the Lobster, which is where the pictures came from. When you saw them, it was pretty obvious how it works, but it is hard to describe how the shifty rod bits go across.

                            Joe
                            old pics new zealand pics new pics
                            Where have I been riding? (GPS)

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                            • #29
                              Originally posted by juggleaddict View Post
                              Originally posted by justtysen View Post
                              Yes, in fact most three speed hubs have a reduction gear as it is simply the inverse of the higher gear. In high gear, the sun gear is the input (cranks) and the ring gear is the output (hub) if you switched the bindings around so that the cranks turned the ring gear and the hub was turned by the sun gear than you would have a lower than 1:1 gearing.
                              That's way more complicated than it needs to be, you really just need to make the gears on surrounding the main gear larger, and make the main gear smaller. that way all you're changing is the diameter, not the construction of the entire hub assembly.
                              Considering that I made two significant errors, such that my gears were operating in reverse and that my "high gear" was really a low gear and vice versa, I'd certainly say it was more complicated than I expected.

                              Still though, I don't think making the planet gears larger than the sun gear will have the desired result. You still have to take into account the ring gear. In the Schlumpf set up, if all you did was make the planet gears larger than the sun gear, they would rotate less than once for a rotation of the planet carrier, but that <1 rotation would be added to the full rotation of the carrier, thereby turning the ring gear (Schlumpf's output) 1+<1 rotations.

                              Originally posted by joemarshall View Post
                              ...but it is hard to describe how the shifty rod bits go across.
                              It looks like the shifter slides a dual ringed clutch along the crank spindle, and that the pegged teeth on either side of that clutch are spring loaded against each other. Their engagement being staggered on each side, so that when shifting one side is disengaged, and the other side's pegs are compressed, after enough of a rotation (that small coasting section) these pegs reach their corresponding notches and pop out, engaging the new side. The spring tension in the shifter itself would have to be greater than that in the combined pegs to prevent them from shifting the clutch back.

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                              • #30
                                Originally posted by semach.the.monkey View Post
                                I was going to add to this thread to say that I have some pretty decent photos of the hub internals... but those photos (well, top 4 anyway) are mine. Oh well.STM
                                STM,
                                Thanks for taking the Schlumpf hub pics at RTL. Whenever I see great unicycle pics like those I collect them for the archive for just such a discussion. Now that I know they're yours I'll give you credit next time. I didn't mean to take the wind out of your sales. Credit where it's due.
                                Geoff
                                monocycle monstrosity

                                Mustn't sleep! Clowns will eat me!

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