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Homemade Geared hub - high speed only

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  • #16
    Awesome. Please keep sharing what you have been doing. I look forward to reading about and watching how your geared hub goes.
    Dave, Sydney Australia
    20" Nimbus Trials
    20" Impact Trials
    27.5" MAD4ONE Muni

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    • #17
      Do you have an as-built drawing set, Scott? What gears did you use? I'm also interested in the robustness of the aluminum planet carrier and the pinned attachment to the shaft. It's a pretty project.
      -Greg Harper

      Nipples...do you ever have enough?

      Change is good. Bills are better.

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      • #18
        Originally posted by harper View Post
        Do you have an as-built drawing set, Scott? What gears did you use? I'm also interested in the robustness of the aluminum planet carrier and the pinned attachment to the shaft. It's a pretty project.
        The video at 3:20 said he used gears from KHK Gears, Carbon Steel, 0.8 pitch, 8mm wide. Sun - 40 teeth, Ring - 80 teeth, Planets , 20 teeth.

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        • #19
          Originally posted by JimT View Post
          The video at 3:20 said he used gears from KHK Gears, Carbon Steel, 0.8 pitch, 8mm wide. Sun - 40 teeth, Ring - 80 teeth, Planets , 20 teeth.
          Thanks. I didn't have the audio on.
          -Greg Harper

          Nipples...do you ever have enough?

          Change is good. Bills are better.

          Comment


          • #20
            Great geared hub!

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            • #21
              Thanks for all the positive feedback! It's great to share this project with a group that really appreciates it. Here are some answers:

              - Appreciate the JD grease suggestion, I'm in the heart of JD country. Ordering the grease was being a little lazy, but since Florian has found the perfect grease, I didn't want to take a chance and I got the grease just a couple days after ordering (thanks Buzz!).

              - I think I spent about 80 hours building the hub. A second one would go faster. If I had a 4 1/2" block of aluminum instead of 4" I could simplify the design quite a bit and make the hub shell in one piece instead of two.

              - Cost:
              Gears from KHK $180
              5 ball Bearings - $25
              McMaster-Carr - axles, snap rings - $40 (enough for 2 or 3 hubs)
              Scrap metal - $10
              Misc hardware store trips $5
              Total - $ 260

              Rim, tire, spokes - $100
              UDC - cranks, bearing adapter - $30

              The hub is kind of heavy (can't find the scrap of paper I wrote the wight down), but the rim/tire are light. Total uni weight in a stock nimbus 24" muni frame is 15.4 lbs.

              Yes, I am concerned about the aluminum planet carrier. Initially using the retainer plates allowed the planet axles to turn, which is a bad design, especially with steel on aluminum. It was starting to open up the clearance in the holes. I have since put in longer axles with a hole drilled in each end and safety wired them together to retain them and prevent rotation. Still not crazy about that method and I plan to make a steel planet carrier when I get some time.

              The electric assist hub is quite a feat! Very impressive! I went through the same process of trying to figure out how to do a splined axle for isis cranks and couldn't come up with a good way. I don't have the tooling and the main axle would be really big. 17mm bearings are readily available. Getting a good solid fit between the cranks and axle has been one of the bigger challenges.

              Making and selling these? I would love to, but I just don't have time. I think there is a market for a simple non-shifting hub. I don't think anything in this design is novel enough to be patent-able (the real magic is in being able to shift gears). I would be happy to share drawings and ideas with anyone who wants to make one of these. My as built drawings are a little rough right now and I'm going on a trip soon, but later in the month I should have time to clean them up and will post them. I have a friend with a CNC machine shop and I may see what he would charge to crank out some of the more machining intensive parts. In the winter in would be fun to make some more, but now the weather is good for riding and I spent too much of the winter away form my wife in the shop!

              Riding has been going really well. I was expecting it to take longer to get used to. It seems more comfortable to ride than ungeared. I think the extra resistance on the pedals helps take some weight out of the saddle? Spokes for the 29" wheel build are on the way!
              Muni mantra "I ride what I can, walk what I can't; the more I ride the less I walk."

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              • #22
                Another item of interest is the backlash in thousandths of an inch (or in mm) measured at 150mm from the hub center line. This is where the center of a pedal axis is on a 6" or 150mm crank. I was able to hold it down to 0.05" or about 1.25mm on mine.

                Here is the website.
                Last edited by harper; 2018-03-03, 06:11 PM.
                -Greg Harper

                Nipples...do you ever have enough?

                Change is good. Bills are better.

                Comment


                • #23
                  Nice design and impressive build!
                  Originally posted by harper View Post
                  Thanks. I didn't have the audio on.
                  The information on the gears used was in a text overlay, not in the audio.

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                  • #24
                    Originally posted by Klaas Bil View Post
                    Nice design and impressive build!
                    The information on the gears used was in a text overlay, not in the audio.
                    I guess I didn't have my brain on either. No surprise these days.
                    -Greg Harper

                    Nipples...do you ever have enough?

                    Change is good. Bills are better.

                    Comment


                    • #25
                      Harper,

                      Your hub looks really nice! I wish I had seen your design earlier. The torque arm lets you use much bigger bearings which is nice. The bearings I have between the sun gear carrier and axle are kind of small, but the smallest still has a load rating of 300lbs, so I think they will be fine for road riding.

                      Good idea measuring the backlash. I may monitor this to see if things are wearing. The backlash is more than double yours - 0.125". It's very ride able, but kind of like having a loose crank. During the preliminary assembly it was so tight it hardly moved, so I started opening up clearances in the planet gears and may have gotten a little carried away. It rolls easy at least. I hope to reduce the backlash with the steel planet carrier.

                      The pin connection between the shaft and planet carrier may be the culprit again since it seems like more movement that I should get from a few thousandth of extra clearance in the plant gears (need to make that steel planet carrier). Once I have a steel planet carrier I may just weld it to the shaft instead of using a pin.
                      Muni mantra "I ride what I can, walk what I can't; the more I ride the less I walk."

                      Comment


                      • #26
                        Hub laced up in 29" wheel now

                        So I got pretty comfortable on the 24" wheel, feeling like I can spin faster, handling wind and small hills, and got my average speed for a 4 mile ride up to 9 mph. So I laced the geared hub in a 29" Nimbus Dominator 2 rim with a Racing Ralph tire.

                        Going to the 29" wheel was a bigger adjustment than I thought. I had a lot of problems mounting and riding was pretty tense - not many UPD's, but I constantly felt like I was about to. Like all things unicycling, it is getting much more comfortable after 10 miles of riding. My last two mounts I made it on the first try and on a 4 mile, out and back ride, averaged 9 mph into the light (but really tiring) wind and 10 mph on the way back. So I think this will work out with more practice. I can't imagine riding a geared 36er Underthelake!

                        Mechanically, the backlash I measured before turned out to be some slop in the pin to planet gear carrier. I put a bigger tighter fitting pin in and the backlash at the crank is down to 0.030". Feels better. I put a rim brake on the 29'er and that is nice too. Next up - I have a pivotal seat post (thanks Caseytronic) and may try a KH Fusion One saddle for long ride comfort. Still planning on making steel planet carrier and welding it to the shaft for longer term reliability.
                        Attached Files
                        Muni mantra "I ride what I can, walk what I can't; the more I ride the less I walk."

                        Comment


                        • #27
                          Originally posted by uniscott View Post

                          Mechanically, the backlash I measured before turned out to be some slop in the pin to planet gear carrier. I put a bigger tighter fitting pin in and the backlash at the crank is down to 0.030". Feels better.
                          Measured at a 150mm radius? Excellent.
                          -Greg Harper

                          Nipples...do you ever have enough?

                          Change is good. Bills are better.

                          Comment


                          • #28
                            Originally posted by uniscott View Post
                            So I got pretty comfortable on the 24" wheel, feeling like I can spin faster, handling wind and small hills, and got my average speed for a 4 mile ride up to 9 mph. So I laced the geared hub in a 29" Nimbus Dominator 2 rim with a Racing Ralph tire.

                            Going to the 29" wheel was a bigger adjustment than I thought. I had a lot of problems mounting and riding was pretty tense - not many UPD's, but I constantly felt like I was about to. Like all things unicycling, it is getting much more comfortable after 10 miles of riding. My last two mounts I made it on the first try and on a 4 mile, out and back ride, averaged 9 mph into the light (but really tiring) wind and 10 mph on the way back. So I think this will work out with more practice. I can't imagine riding a geared 36er Underthelake!

                            Mechanically, the backlash I measured before turned out to be some slop in the pin to planet gear carrier. I put a bigger tighter fitting pin in and the backlash at the crank is down to 0.030". Feels better. I put a rim brake on the 29'er and that is nice too. Next up - I have a pivotal seat post (thanks Caseytronic) and may try a KH Fusion One saddle for long ride comfort. Still planning on making steel planet carrier and welding it to the shaft for longer term reliability.
                            Why don't use a pre-assembled Huni-rex? I mod it to use a fat tire and a disc brake and I'm not good in modding, nor own the right tools. You could easily and cheap get what kind of wheel do you prefer. I haven't done a review, but I' ll do it soon, when I'll be inspired to control and correct my english writing

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                            • #29
                              The huni-Rex looks like a cool design and the price is great, is anyone making/selling them now? Not sure where you could get one, at least in the States anyway.
                              Muni mantra "I ride what I can, walk what I can't; the more I ride the less I walk."

                              Comment


                              • #30
                                http://www.jokolarte.com/cerca.asp?search_key=pedala or
                                http://funicycle.com/magasin/unicycl...g7b69rakk70391 or some times appear a used one on ebay

                                Just remember that you MUST mod it to accept a wider or bigger wheel to solve any possible pedal stroke issue!

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