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  1. #26
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    Oh, man. I'm loving this. Good on you for going through with it.

    Sorry to hear about your knees. My father in law was a life long marathoner and soccer player and has had both knees and both hips replaced. Moves much better now.

    Thanks for the update. I look forward to seeing more.

  2. #27
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    Why I'm probably not going to build a 3 speed

    Hey guys, sorry for the long wait between updates. I may have warned earlier, but this is going to be a long drawn out process, and I'm super busy with a bunch of other stuff. Also Iíll apologize in advance for writing a small novelÖ

    Anyway, I finished the design which took me forever, but I am not all that happy with it. The overall design isn't bad, but now that I have seen it all born out in front of me I am thinking I might just scrap the whole idea and go 2 speed kickback shifting design. I donít like it for 2 reasons: A) Iíd like to keep the feel of a single speed (clean looks, simplified riding experience). B) A three speed just doesnít offer that many advantages over an eight speed (efficiency, weight, cost).

    Here is the issue - as I see it - with designing any 3 speed mtb hub:
    Once you have a robust infrastructure to shift gears within a moving hub, there really isn't a reason NOT to add a few more gears. Why make a 3 speed hub that weighs and costs only slightly less than an 8 speed hub? What do you gain by trading off 5 more gears? A little simplicity (not much though), a little weight, and a little cost. Itís simply a matter of once you are able to work clutches inside a gear hub from a shifter at the handlebars, adding a gear or two really isn't much of a penalty, and if you add a gear or two you might as well chain them together in some way to create more gear ratios. Next thing you know you have an 8 speed gear hub. From my research, the 3 speed hubs today arenít able to stand up to the abuse of mountain biking, and to build them so that they would be able to, your cost, weight, and efficiency would be approaching that of an 8 speed anyway. Maybe this has already been said somewhere, but it was a novel idea to me.

    So at the end of the day, letís just cut that granny gear out, and make us a kick back hubÖ. Iím going to put up info about that in a couple minutes, but these are entirely separate ideas, so I figured I would split them up into two posts.

    Here is a teaser of my hub that I built in CATIA BTW, not going to go into a full explanation unless you want it, that would take way too long

    designing a 3 speed mountain biking hub-whole-shebang.jpgdesigning a 3 speed mountain biking hub-carrier-planetary.jpgdesigning a 3 speed mountain biking hub-hub.jpg

  3. #28
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    2 speed kickback

    Iíve looked at the current market for 2 speed kickbacks, and nothing seems to be built for mountain biking. There is also the option of the Schumpf 2 speed cranks, but it doesnít come in the ranges I want, and itís fricking 700 dollars (what the hellÖ).

    The overall design would be super simple for the 2 speed kick back (I may have said that about the 3 speed, but the realities of design have made me feel otherwise). Essentially, I would have a free hub body that engaged a driver, that driver would be splined and have clutch that would be cam shifted by back pedaling. The clutch would directly engage the hub shell, and then when shifted it would directly engage the planet carrier of a planet assembly.

    The other option would be to have 2 roller clutches, 1 for engaging the hubshell directly, and another for engaging the planet carrier. Then all you would need is to be able to lock the sun gear to the axle when you want to get into the higher gear.

    Iím leaning toward option 1, mainly because this design is easily transferable to different gearing arrangements. Say that you wanted a direct 60 gi gear, and a 40 gi reduction gear. You could essentially design in whatever gear you wanted to be direct drive, and change that to whatever gear you wanted to be your other gearing. Also, funnily enough you could make it a fixed gear hub too. Although kicking back would involve literally going backwards (or just lifting your rear wheel and backpedaling while stopped).

    Anyway Iíd imagine the concept would be a lot like this: (with different shifting mechanisms, and well a lot of other differences too)

    Kris Holm / Schlumpf Geared Unicycle Hub: How It's Made - YouTube

  4. #29
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    Quote Originally Posted by jimhead88 View Post
    Iíve looked at the current market for 2 speed kickbacks, and nothing seems to be built for mountain biking. There is also the option of the Schumpf 2 speed cranks, but it doesnít come in the ranges I want, and itís fricking 700 dollars (what the hellÖ).

    The overall design would be super simple for the 2 speed kick back (I may have said that about the 3 speed, but the realities of design have made me feel otherwise). Essentially, I would have a free hub body that engaged a driver, that driver would be splined and have clutch that would be cam shifted by back pedaling. The clutch would directly engage the hub shell, and then when shifted it would directly engage the planet carrier of a planet assembly.

    The other option would be to have 2 roller clutches, 1 for engaging the hubshell directly, and another for engaging the planet carrier. Then all you would need is to be able to lock the sun gear to the axle when you want to get into the higher gear.

    Iím leaning toward option 1, mainly because this design is easily transferable to different gearing arrangements. Say that you wanted a direct 60 gi gear, and a 40 gi reduction gear. You could essentially design in whatever gear you wanted to be direct drive, and change that to whatever gear you wanted to be your other gearing. Also, funnily enough you could make it a fixed gear hub too. Although kicking back would involve literally going backwards (or just lifting your rear wheel and backpedaling while stopped).

    Anyway Iíd imagine the concept would be a lot like this: (with different shifting mechanisms, and well a lot of other differences too)

    Kris Holm / Schlumpf Geared Unicycle Hub: How It's Made - YouTube
    not sure if you've seen IB13: Sturmey Archer introduces new 5 speed hubs for 2014, adds new 2 Speed Disc Hubs in 135mm and 120mm spacings

    or Product Specs | Patterson Bike

    I've love a reliable 2 speed that would take a mtb beating. The patterson isn't mtb rated and only fits a 68mm bb shell and who knows if the sturmey is strong enough or will be available widely. The idea of keeping the extra weight in the bb area rather than way out back is appealling after riding single speed for a long time

  5. #30
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    Ya, I love the idea of having everything at your bottom bracket but I'm not such a fan of all the crank options. One issue is that the step is gigantic. I'm pretty sure this stems from the necessity to have a larger sun gear. You need your sun gear stationary for closer gear ratios, but you also need to pass your spindle through it, on a hub gear you just have to fix it to your stationary axle. So this means you need to have a large sun, it would follow that you also need to have a large Ring gear to get a gear range more usable for "singlespeed" types. A big ring gear makes mounting your chainring a little more difficult too. None of these are insurmountable issues, but the other problem is that most manufacturers market them as a substitute for a front derailleur, or something to increase the gear range of whatever you have at the back of your bike, not as a stand alone 2 speed. So they design it with a wider range.

    Reminder, I am not some expert on this subject and could be completely off base with my conjecture. If I am, please tell me.

    To the sturmey archer s2, I'm considering giving that a shot knowing full well that it probably won't be up to the task of mountain biking. I would love to be surprised though. It makes sense that if I am going to build my own kickback, it would be good to get my hands on an existing designs, and see how it could be improved upon. If I buy it, I will give a full on review in the IGH forum for those interested. Even if it is up to the task, the build quality is pretty low, so I will probably still look into building my own, or maybe even making improvements to the existing hub. Now that I say that, it might be kind of cool machining higher quality internals for the sturmey archer kickback before going whole hog and starting my own hub from the ground up. We shall see though.

  6. #31
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    The original concept was intriguing, but I was wondering how you planned to transmit drive to a sun gear. Probably not impossible, but in the realm of bicycle gearhubs, the sun gear has always served as the reactionary gear in the planetary geartrain. It was fun to think someone was thinking outside that box.
    Dan

  7. #32
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    Quote Originally Posted by Dan Burkhart View Post
    The original concept was intriguing, but I was wondering how you planned to transmit drive to a sun gear. Probably not impossible, but in the realm of bicycle gearhubs, the sun gear has always served as the reactionary gear in the planetary geartrain. It was fun to think someone was thinking outside that box.
    Dan
    First off, let me say I love your videos and am looking forward to your rundown of Alfine 8's hub. In my original design I was planning on having the sun gear coupled to the driver in second gear. If you look at my pictures I posted and didn't explain at all, what I am planning to do is have the sun slide from side to side, on one side the sun would be coupled to to axle giving you an overdrive, and on the other side couple to the driver giving you a "unity" gear. The driver is also coupled to the planet carrier at all times via a roller feewheel clutch. The trick was that you can drive your sun both ways but not your planet carrier. Your planet carrier would have a one way clutch on the axle so that when you drive your sun gear in reverse your planet carrier would freewheel on your driver (which is moving backwards) and get stopped on your axle, essentially fixing it in place. With a stationary planet carrier your planets now become essentially idler gears and your ring gear rotates in the opposite direction of your sun gear at a ratio equal to the number of teeth on the sun divided by the number on your ring gear. In my design it would be 22/50.

    I'm short on time right now, but I can post more pictures later. Does this make sense?

    I'm still a little luke warm on the design for a few reasons. But mainly with 2 roller clutches it would be really heavy, however I don't want to have pawl and ratchets because your reverse gear is always engaged, so it would be ratcheting away all the time. The advantage of not actively engaging the first gear somehow with your shifter, is that you can always just start pedaling backwards when you get caught with your pants down halfway up a hill.

    Finally, the sun gear would be moved back and forth with some sort of bell crank... probably just a shimano bell crank with a friction shifter. Gotta run, hope this helps!

  8. #33
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    Quote Originally Posted by jimhead88 View Post
    First off, let me say I love your videos and am looking forward to your rundown of Alfine 8's hub. In my original design I was planning on having the sun gear coupled to the driver in second gear. If you look at my pictures I posted and didn't explain at all, what I am planning to do is have the sun slide from side to side, on one side the sun would be coupled to to axle giving you an overdrive, and on the other side couple to the driver giving you a "unity" gear. The driver is also coupled to the planet carrier at all times via a roller feewheel clutch. The trick was that you can drive your sun both ways but not your planet carrier. Your planet carrier would have a one way clutch on the axle so that when you drive your sun gear in reverse your planet carrier would freewheel on your driver (which is moving backwards) and get stopped on your axle, essentially fixing it in place. With a stationary planet carrier your planets now become essentially idler gears and your ring gear rotates in the opposite direction of your sun gear at a ratio equal to the number of teeth on the sun divided by the number on your ring gear. In my design it would be 22/50.

    I'm short on time right now, but I can post more pictures later. Does this make sense?

    I'm still a little luke warm on the design for a few reasons. But mainly with 2 roller clutches it would be really heavy, however I don't want to have pawl and ratchets because your reverse gear is always engaged, so it would be ratcheting away all the time. The advantage of not actively engaging the first gear somehow with your shifter, is that you can always just start pedaling backwards when you get caught with your pants down halfway up a hill.

    Finally, the sun gear would be moved back and forth with some sort of bell crank... probably just a shimano bell crank with a friction shifter. Gotta run, hope this helps!
    Yep, it makes sense. Making the planet carrier the reactionary reverses the direction of the input at the output whichever way it flows.
    Speaking strictly for myself, I'm not averse to some ratcheting noise. I consider it mechanical music, but there is no question roller clutches are superior in some ways.

  9. #34
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    Re: designing a 3 speed mountain biking hub

    Make this as silent as you possibly can, no reverse pedalling of any kind, and build a prototype for under $1000 and I will personally partner with you and mass produce this (no joke).

    Also make sure it doesn't weigh 4 pounds.

    This would fit a tiny market, but one that currently has not much going for it (the market between single speeders and 1xX's). A 1x3 would be a great commuter hub (simply because of weight and price, since less gears could mean less cost)

  10. #35
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    Mechanical music... I like that. I think the reason roller clutches aren't used more is because of their torque density, they just won't be as light as a pawl and ratchet system built of the same quality. I'd also like to be able to play around with building some roller clutches and not relying on buying off the shelf roller clutches... If only I owned my own hub company...

    I guess I am not abandoning the idea, I just like the idea of not having any shifting mechanism. I'm a perfectly happy single speeder, until spin out on pavement... By dropping the lowest reverse gear you simplify a lot of the internals.

    You could potentially just make a suuuuper simple hub that worked in the same way I described except just drop the over-drive. This would essentially function the same as any retro direct drive, without all the crazy chains hanging out, it would all be internal. Fix the Planet carrier permanently, and have a rearward facing overrunning clutch on your driver: Forward, freewheel engages the hub shell; backwards, rearward facing freewheel engages the sun/ring (depending on if you wanted to gear up or down). Of course, I was fine with sometimes accessing a bailout gear by pedaling backwards, but having one that I used all the time might be a different story. If I'm going to build a two speed though, i'd rather just add a little complexity and make it a kick-back. Still though, the utter simplicity of a hub like this is nothing to be scoffed at.

  11. #36
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    wait doesn't the internals get to be beefier in a 3speed than more speed? If i was designing a 3speed i would make the internals beefy and indestructable. as opposed to the 8 and 11 speed crapout there. also less moving parts = better life.
    Rule #9 // If you are out riding in bad weather, it means you are a badass. Period.

    Quote Originally Posted by iheartbicycles View Post
    Specialized sucks ass.

  12. #37
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    Quote Originally Posted by jimhead88 View Post
    Mechanical music... I like that. I think the reason roller clutches aren't used more is because of their torque density, they just won't be as light as a pawl and ratchet system built of the same quality. I'd also like to be able to play around with building some roller clutches and not relying on buying off the shelf roller clutches... If only I owned my own hub company...

    I guess I am not abandoning the idea, I just like the idea of not having any shifting mechanism. I'm a perfectly happy single speeder, until spin out on pavement... By dropping the lowest reverse gear you simplify a lot of the internals.

    You could potentially just make a suuuuper simple hub that worked in the same way I described except just drop the over-drive. This would essentially function the same as any retro direct drive, without all the crazy chains hanging out, it would all be internal. Fix the Planet carrier permanently, and have a rearward facing overrunning clutch on your driver: Forward, freewheel engages the hub shell; backwards, rearward facing freewheel engages the sun/ring (depending on if you wanted to gear up or down). Of course, I was fine with sometimes accessing a bailout gear by pedaling backwards, but having one that I used all the time might be a different story. If I'm going to build a two speed though, i'd rather just add a little complexity and make it a kick-back. Still though, the utter simplicity of a hub like this is nothing to be scoffed at.
    I have been on my tp stealth now for over a year. it just works. I'm gonna crack it open now in about a month to see how its holding up. maybe i can post some pics here.

    the thing with pawl/ratchet systems is this: they are all ****. the best one is white industries because they use real tool steel correctly hardened.
    for springs you need to use real spring steel otherwise they break quite fast. like 5160 or L6 (at its toughness peak), and possibly 6150. for the ring and pawls you need (very) tough, hard, strong and abrasion resistant steel like cpm 1v and 3v. a2, d2 (well maybe), 52100. etc, tough stuff that gets hard. and no one really makes this.
    Rule #9 // If you are out riding in bad weather, it means you are a badass. Period.

    Quote Originally Posted by iheartbicycles View Post
    Specialized sucks ass.

  13. #38
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    Quote Originally Posted by car bone View Post
    wait doesn't the internals get to be beefier in a 3speed than more speed? If i was designing a 3speed i would make the internals beefy and indestructable. as opposed to the 8 and 11 speed crapout there. also less moving parts = better life.
    Yes.. you do get more space. But from all I have read, rohloff and alfine 8's hold up to the riggers of mountain biking adequately. And if something breaks, from what I have gathered, it's not the gears themselves, it's some freewheel assembly. Dan seems to be very well versed in actual hubs designs and could probably point out the weak spots better than I can. Actually, Dan, what are the weakest spots in most hub designs in your experience? My point that I was trying to make earlier was that most of the designs I have come up with aren't going to have gigantic mechanical advantages over an 8 speed.

    I was in a little bit of a cynical mood I guess, and just frustrated that I couldn't make it worlds better than what is out there. I may be missing the point however, in that it's mentally simple as well: Climb, Flats, downhill/pavement.

    Lastly I totally agree with you about having a roller clutch. It seems it would totally be worth any extra weight to have it dead silent, and instant engagement. I know people always say weight is a huge deal, but in the grand scheme of things, having something that's relatively heavy but runs smooth and efficiently is a trade off I'm willing to make.

  14. #39
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    I've been following this thread with interest as I've thought for a long time that a reasonably light three speed (or even two speed) hub would suit my needs 99% of the time.
    What I couldn't live with is kickback gear changing - it might be fine for road/non technical off-road but not being able to ratchet to position my cranks and time pedal strokes in technical stuff is something that I couldn't get used to.
    Maybe this is just me though, and possibly I've spent too much time on singlespeeds where ratcheting is a basic technique - a riding friend of mine has commented on how much I do this (even on a geared bike), whereas he rarely does.

  15. #40
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    Quote Originally Posted by jimhead88 View Post
    Yes.. you do get more space. But from all I have read, rohloff and alfine 8's hold up to the riggers of mountain biking adequately. And if something breaks, from what I have gathered, it's not the gears themselves, it's some freewheel assembly. Dan seems to be very well versed in actual hubs designs and could probably point out the weak spots better than I can. Actually, Dan, what are the weakest spots in most hub designs in your experience? My point that I was trying to make earlier was that most of the designs I have come up with aren't going to have gigantic mechanical advantages over an 8 speed.

    I was in a little bit of a cynical mood I guess, and just frustrated that I couldn't make it worlds better than what is out there. I may be missing the point however, in that it's mentally simple as well: Climb, Flats, downhill/pavement.

    Lastly I totally agree with you about having a roller clutch. It seems it would totally be worth any extra weight to have it dead silent, and instant engagement. I know people always say weight is a huge deal, but in the grand scheme of things, having something that's relatively heavy but runs smooth and efficiently is a trade off I'm willing to make.
    The weak points vary with hub design. In indicator spindle (hollow axle) type shifting, it's sliding key and locking ball interfaces with sun gears. In the Shimano Nexus, failures tend to be a result of broken input reduction sun gears and shift pawls. Hard torquing on the hub when a shift pawl is not fully extended into the internal splines in a sun gear can be a recipe for failure. This is why accurate shift cable adjustment, and non binding cable is critical, and also why shifting under pedaling torque should be avoided. It might be possible to do, but moving shift pawls in and out of engagement with sun gears without breaking torque puts a great deal of wear on the pawls, and can result in incomplete engagement.

  16. #41
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    Quote Originally Posted by jimhead88 View Post
    Yes.. you do get more space. But from all I have read, rohloff and alfine 8's hold up to the riggers of mountain biking adequately. And if something breaks, from what I have gathered, it's not the gears themselves, it's some freewheel assembly. Dan seems to be very well versed in actual hubs designs and could probably point out the weak spots better than I can. Actually, Dan, what are the weakest spots in most hub designs in your experience? My point that I was trying to make earlier was that most of the designs I have come up with aren't going to have gigantic mechanical advantages over an 8 speed.

    I was in a little bit of a cynical mood I guess, and just frustrated that I couldn't make it worlds better than what is out there. I may be missing the point however, in that it's mentally simple as well: Climb, Flats, downhill/pavement.

    Lastly I totally agree with you about having a roller clutch. It seems it would totally be worth any extra weight to have it dead silent, and instant engagement. I know people always say weight is a huge deal, but in the grand scheme of things, having something that's relatively heavy but runs smooth and efficiently is a trade off I'm willing to make.
    I am also finding this very interesting, so I will throw my opinion out there as well! First off, there is only one hub currently available that can handle the rigors of real mountain biking, Rohloff. I know people are going to chime in saying they are using an Alfine 8 and it works fine. For many people, it works OK, if you are really careful with shift technique, making sure your shift alignment is good often, don't go below the recommended input ratio, etc. Even if you are careful with the above stuff, it can still break. Also, the recommended low ratio for the Alfine 8 is not low enough for real mountain biking.

    So anyway, I would love to see another gearhub that can stand up to real mountain biking, whether it's a 2, 3, 5, 8 speed whatever! Personally, I think a 5 speed hub would be ideal for the kind of riding I do (tight, techy singlestack). I can see the appeal of a super simple 2 speed hub, and would probably get one if it really was robust enough, but I think the market would be significantly bigger for a 5 or 8 speed unit.

    Just thinking out loud here: I wonder if it's possible to just beef up an Alfine 8? If what you say is correct about the failure mode, maybe it's just a matter of replacing the fragile bits with higher quality, tougher materials?

    I have no idea about the inner workings of these hubs, so just let me know if I am way off base!

    Mark

  17. #42
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    Quote Originally Posted by bikeny View Post
    I am also finding this very interesting, so I will throw my opinion out there as well! First off, there is only one hub currently available that can handle the rigors of real mountain biking, Rohloff. I know people are going to chime in saying they are using an Alfine 8 and it works fine. For many people, it works OK, if you are really careful with shift technique, making sure your shift alignment is good often, don't go below the recommended input ratio, etc. Even if you are careful with the above stuff, it can still break. Also, the recommended low ratio for the Alfine 8 is not low enough for real mountain biking.

    So anyway, I would love to see another gearhub that can stand up to real mountain biking, whether it's a 2, 3, 5, 8 speed whatever! Personally, I think a 5 speed hub would be ideal for the kind of riding I do (tight, techy singlestack). I can see the appeal of a super simple 2 speed hub, and would probably get one if it really was robust enough, but I think the market would be significantly bigger for a 5 or 8 speed unit.

    Just thinking out loud here: I wonder if it's possible to just beef up an Alfine 8? If what you say is correct about the failure mode, maybe it's just a matter of replacing the fragile bits with higher quality, tougher materials?

    I have no idea about the inner workings of these hubs, so just let me know if I am way off base!

    Mark
    Another apparent weakness in the Alfine design was the straight cut gears on the input reduction sun and planetary gears. This was addressed in the 11 speed with helical gears. This introduces the end thrust factor which must be dealt with in some manner. I've not explored an 11 speed, so I'm not sure how they engineered that. Probably just with thrust washers, but that introduces another wear factor, so there are no easy answers.

  18. #43
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    What I couldn't live with is kickback gear changing - it might be fine for road/non technical off-road but not being able to ratchet to position my cranks and time pedal strokes in technical stuff is something that I couldn't get used to.
    Ya, that has been a major concern of mine. The basic philosophy (if you can call it that), is that it would be like a single speed, but you could access another gearing if conditions changed. So not as much switching in between while mountain biking, but having an over drive when your not mountain biking. With this in mind, the most optimal system would be to create a mechanism that only shifted once per revolution and would revert back to its starting position when you pedaled forward. Since you would probably have something like a gear ratio of 33-20 (assuming a 29er), this would actually amount to 2/3's of a revolution. The idea being that only when you did a full revolution without ever going in the forward direction would you change gears. Would this solve your problem?

    I'm starting to realize that two designs are going to be necessary. 1) a 2 speed kickback that fits into the single speed aesthetic; and 2) a 3-5 speed hub that can take mtb abuse, and no back pedaling.

    The weak points vary with hub design. In indicator spindle (hollow axle) type shifting, it's sliding key and locking ball interfaces with sun gears. In the Shimano Nexus, failures tend to be a result of broken input reduction sun gears and shift pawls. Hard torquing on the hub when a shift pawl is not fully extended into the internal splines in a sun gear can be a recipe for failure. This is why accurate shift cable adjustment, and non binding cable is critical, and also why shifting under pedaling torque should be avoided. It might be possible to do, but moving shift pawls in and out of engagement with sun gears without breaking torque puts a great deal of wear on the pawls, and can result in incomplete engagement.
    Love it! I have re-evaluated my 3 speed hub aspirations and am currently working on a clutch system that would basically work like a traditional 3 speed hubs. I do think there might be something here, but it all rests (as you have pointed out), on the gear changing mechanism. My newest (my CAD files are now up to V7) is basically 2 clutches with an always stationary sun, both clutches can engage the carrier and ring gears, one clutch is attached to the hub (output), and one is attached to the driver (input). So 1) drive coupled with ring, output coupled with carrier; 2) both coupled with carrier; 3) drive coupled with carrier, output coupled with ring gear. This basic design sounds simple but that's because everything rests on the clutch, and if it can take the abuse. I'm at work and gotta run, but I will try to get a picture of what I got going on before the end of the day.

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