Seeking geared unicycle prototype demonstrater/collaborator for startup company.

[UnimakerX]

@AJ KJ

I have never ridden a Schlumpf or otherwise geared unicycle, but 4 ratios seems to be reaching excessive. With 4 ratios, and two of them being overdrives, you’d seem to quickly reach a point where the weight of the unicycle is out of balance with the torque lost when shifting to a higher gear. Would your design limit rotational weight, or even better; all weight?

Also, you could likely shift between planetary gears if that’s the approach you choose. You could have the shifting mechanism move the sun gear to a different set of planetary gears that are all rotating with the cranks and ring gear, but only one would be engaged with the sun gear at a time.

To simply the points:

• many planet gears (driven by cranks, don’t slide side to side)
• one sun gear that changes position
• one long (along the axis of rotation) ring gear that has a changing internal
  circumference to accommodate different sized planet gears. This would
  connect to the spokes/rim

I’m kind of breaking a promise not to post this weekend, but thanks for the ideal about moving the sun gear and multiple planetary gears. AJKJ.:)…it has inspired me to rethink some of my old ideals and modify them…now with that being said the number of potentials speeds are virtually “limitless”, limited only by the width of the hub I would assume.
…so even if the gear ratios produced,are unridable it would be a fun build just to do it.

Now I decided to “reincarnate” the old principle design keys you mentioned… Of course I have added a few twist to the ideal, including underdrive…

Let me also tell you I scrapped the third bearing size in the ideal and came up with a bearing race structure ideal consisting of many smaller bearings…which will greatly increase the ability to make it a reality, since manufacturing bearings sizes from scratch would be far too expensive (trying to keep the prototype project under $25,000) according to an employee of Timken bearings.

Now I like to think there is room for everyone to make a geared hub, especially bouin bouin…

Note: still planning on getting the dual chain kits out there but now more interested in making the hub a reality just for experimentation for experimentation sake…for example dual chain unicycles have been done, nobody however has done a 4 speed chain less hub that I can think of.

But…

If nobody else “nudge, nudge, hint, hint” puts a dual chain kits out there then It will sure be on the agenda to aim for manufacturing of said such a product first.

Back to the geared hub current ideal:

Suspected pros: almost any number of gears, more straight forward
Design, no need for extremely large bearings, hand shifting…

Suspected cons: complexity, too many parts, high manufacturing cost, heavy weight, the more gears with unicycles perhaps the more difficult to ride…

There are people who have or are building hubs who would know more about this for example bouin, bouin…

For example see below:

3 advantages with bouin bouins ideal

#1, he is farther along the design, and development process.

#2 after making a sketch I would assume his ideal manifested in reality is or will be much lighter

#3 it probably has less parts, complexity is not always a good thing in fact it seems to be the general consensus that the simpler you can make a mechanical solution the better…for example less likely to break down and last but not least it will be easier to manufacture, …(also perhaps more affordable).

One day I will actually open a thread about the project when I have made progress. It’s been a long 6 years since i have wanted this and it’s been longer for more skilled individuals, but now this is an exciting possibility under the right circumstances that I refuse to accede.(give up).

Maybe down the line I will post another thread if not on this thread once notable progress has been made, sooner or later, which could be as soon as month or at the end of the year.

[bouin-bouin]

@UnimakerX

Bouin-bouin I got lost on your page, I didn’t see any plans or sketches or drawings, i’m sure you have them. Perhaps you would like to share them? If not that’s fine.

Here it is.

If a multi geared hub were available, would that make the 36" wheel obsolete?

Tholub suggested in the General Schlumpf thread that he felt the 36" wheel was nothing more than a gimmick, that if unicycles could be geared more like a bicycle, that this wheel size would lose favor. Now these are not Tom’s exact words, it was the impression I got from reading his posts, but it does bring up an interesting question: Why do people ride 36ers? Is it a gimmick as Tom suggested or is there more to it? I’ll start: I ride a 36" wheel because it is more stable at speed than a sma…

I moved long time ago to 125mm bearing distance with disc on the hub ! This is compatible with Nimbus Oracle frames, no more with KH

I forgot to tell that Mad4One from Marco Vitale in Italy is also doing very nice stuff

[johnfoss]

@UnimakerX

Suspected pros: almost any number of gears, more straight forward Design, no need for extremely large bearings, hand shifting…

You said hand shifting?

There was a guy, from Denmark maybe, who had modified a Schlumpf setup for a hand-operated shift lever. Me likey! Sure, shifting with your foot is a great skill to master, but it doesn’t let you shift when you want. It usually takes me several revolutions of the wheel to get it, and of course you can only make the shift at one point in the wheel’s rotation, which is a pretty long distance on a 36". I would love the ability to make a definitive shift-on-the-first-try, whenever I need to. It would totally change the way I rode it, and how often I would shift.

That said, it will obviously complicate the system. The reason Schlumpf uses the hub buttons is to keep things from being more complicated. I hope you can come up with a solution for that!

[UnimakerX]

I said that a little wrong, i plan to incorporate hand shifting in my design…in fact it might not even be possible to install foot shifting in my current ideal theoretically because it will have a solid axle…but anyways John Foss, the Flansberrium frame builder told me all about you. It is a pleasure to have communicated with you sir.

[jrwi]

Deserves Flaming for Pedancy, but…

This is a fun thread! I have nothing to add about geared hubs, and no criticism of anyone’s ambitions to make them more readily available, but there is one thing which has been bugging me throughout.

Let me just leave this here…

ideal
adjective UK ​ /aɪˈdɪəl/ US ​ /aɪˈdiː.əl/
​perfect, or the best possible.

ideal
noun UK ​ /aɪˈdɪəl/ US ​ /aɪˈdiː.əl/
(PRINCIPLE)
a principle or a way of behaving that is of a very high standard.
(PERFECT)
a perfect thing or situation.

VERSUS

idea
noun UK ​ /aɪˈdɪə/ US ​ /aɪˈdiː.ə/
(SUGGESTION)
a suggestion or plan for doing something.
(KNOWLEDGE)
an understanding, thought, or picture in your mind.
(BELIEF)
a belief or opinion.
(PURPOSE)
a purpose or reason for doing something.

[bouin-bouin]

@UnimakerX

I said that a little wrong, i plan to incorporate hand shifting in my design…in fact it might not even be possible to install foot shifting in my current ideal theoretically because it will have a solid axle…but anyways John Foss, the Flansberrium frame builder told me all about you. It is a pleasure to have communicated with you sir.

Did you have a look on my design ? It has a twin cable shifting system

[bouin-bouin]

@johnfoss

You said hand shifting?

There was a guy, from Denmark maybe, who had modified a Schlumpf setup for a hand-operated shift lever. Me likey! Sure, shifting with your foot is a great skill to master, but it doesn’t let you shift when you want. It usually takes me several revolutions of the wheel to get it, and of course you can only make the shift at one point in the wheel’s rotation, which is a pretty long distance on a 36". I would love the ability to make a definitive shift-on-the-first-try, whenever I need to. It would totally change the way I rode it, and how often I would shift.

That said, it will obviously complicate the system. The reason Schlumpf uses the hub buttons is to keep things from being more complicated. I hope you can come up with a solution for that!

John, here are photos from hands shifted Schlumpf hub

There is a small lever attached to the Inside of each crank, a cable is attached to one side of this small lever and goes through the crank above the Schlumpf push button. There is another small lever attached to the frame and controlled by hand and cable.

The guy showed it at Italy Unicon to Kris and Florian, but they decided not to propose it …

[UniDreamerFR]

Very ingenious solution, but it’s far too complicated to transpose this DIY modification into a realistic proposition.

[aracer]

@UniDreamerFR

Very ingenious solution, but it’s far too complicated to transpose this DIY modification into a realistic proposition.

I agree - it’s even too much trouble to bother duplicating as a DIY mod for most of us (I have the tools and sufficient skill that I could if I wanted). Any production shifter has to lead directly into the hub via the fixed part which attaches to the frame rather than going via the cranks - which is what bouin-bouin’s design seems to do.

[saskatchewanian]

Ahh, it took me way too long to figure out how that hand shifter worked. The lever on the frame rotates into the way of the lever on the cranks which then pull the cable that goes through the crank and push in the button.

So you still only have one opportunity to shift per revolution.

It’s not exactly complicated, but unless you really can’t foot/ankle shift there isn’t a huge advantage either. I would love to have a system that lets you shift at any crank orientation.

[Superbant]

Couldn’t you put a small servo in the crank that could pull the wire instead? I don’t know how to wirelessly control said servo, or whether it would have enough torque, but maybe that’s an option? It would be able to shift at anytime, and you wouldn’t have to run more cable.

[saskatchewanian]

@Superbant

Couldn’t you put a small servo in the crank that could pull the wire instead? I don’t know how to wirelessly control said servo, or whether it would have enough torque, but maybe that’s an option? It would be able to shift at anytime, and you wouldn’t have to run more cable.

Radio controlled with a lithium battery? Should work. That’s a product that might actually sell if you could make it light and reliable.

EDIT: It would be even better if you somehow got it to fit in the hollow axle instead of the shift rod…

[Superbant]

@saskatchewanian

Radio controlled with a lithium battery? Should work. That’s a product that might actually sell if you could make it light and reliable.

EDIT: It would be even better if you somehow got it to fit in the hollow axle instead of the shift rod…

I think the hub would have to be modded, but it probably could. It might make it even easier, just a coil of wire, magnet, battery and switch. Too bad I don’t have a Schlumpf I could try it with.

EDIT:Anyone have a link to the patent, or other information, so I can see if this is remotely possible.

[UniDreamerFR]

@saskatchewanian

Ahh, it took me way too long to figure out how that hand shifter worked. The lever on the frame rotates into the way of the lever on the cranks which then pull the cable that goes through the crank and push in the button.

So you still only have one opportunity to shift per revolution.

It’s not exactly complicated, but unless you really can’t foot/ankle shift there isn’t a huge advantage either. I would love to have a system that lets you shift at any crank orientation.

As I understand it, the shift rod can only be moved when the cranks are in a 6 o’clock position, could be the worst position to start with, but it could be the better as well for the same reason : dead spot = lowest torque, and the shifting process needs this low torque on the pedals to be complete, but in the other hand having suddenly to deal with the second gear at the exact moment you have zero torque power on the cranks could be an issue, in theory.

the “no torque release = no shift” thing is maybe why even with a system that allows to shift (push the shifting buttons) at any moment instead of once per crank revolution, it would still only shift when the torque on the pedals is released.

I was thinking about another crazy system to shift with a lever, radio assisted : a radio commended system installed on each shoe that would “pop up” for a moment, long enough to reach the button without needing any shoe movement.

Personally I use my “ankle” to shift, but maybe because my pedals have enormous grip my fiveten’s are pretty stuck on it, I can not make any foot rotation around a vertical axe
To reach the button with my ankle I have to make my foot rotate in the same way a motorcyclist leans to the side when he rides on a turn, but because my pedals are large I’m pretty far away from the buttons and it’s hard for me to reach it with my ankles.

So, I made some DIY system from two half of a polystyrene sphère that I wrapped with electric tape and that I put inside the kind of pocket you find on fiveten impact high (you can see the pocket on the following pic).
It makes my “ankle” big enough to easily reach the buttons when I bend my foot without adding much weight, and my shifting success rate has dramatically increased.

I am now using larger “polystyrene” extensions than those you can see in the pic (I gave those one to Pierrox), I use the entire sphere cut in two half instead of some bit of it and it works even better.

So we could imagine a system that makes the same job on each foot but without any foot movement, but that’s would look pretty silly I guess

[aracer]

@Superbant

It might make it even easier, just a coil of wire, magnet, battery and switch. Too bad I don’t have a Schlumpf I could try it with.

You’re describing a solenoid, which was my immediate thought on seeing the servo suggestion - is a better solution for such an application. The only question is whether there’s space inside the hub to fit such a thing (there certainly isn’t enough space on the ends at the cranks). I do have a Schlumpf, but it’s a first gen so not necessarily representative and in any case I’m certainly not taking it apart to check!

[LargeEddie]

@aracer

You’re describing a solenoid, which was my immediate thought on seeing the servo suggestion - is a better solution for such an application. The only question is whether there’s space inside the hub to fit such a thing (there certainly isn’t enough space on the ends at the cranks).

Just about the entire Tour de France peloton uses electronic shifting these days, all but a few too-old-to-change geezer hold-outs. Articles seem evenly split as to whether the derailleurs use servos or stepper motors, which are very different things. I’d say servo motors if I had to guess, since steppers are open-loop and have to be seriously overrated to not lose indexing when they reach their torque limit; both alternatives, too much weight vs screwed up shifting, are quite bad.

Those all use wires AFAIK. Wireless interference between units is probably a big worry in a peloton of 200 riders where they need to work every time right now, but I’m sure it could be made to work for unicycles. Progress in low-power wireless stuff lately has been amazing, and it’d basically be like a PowerTap with data going in the other direction.

[Superbant]

I thought it was called a solenoid, but I didn’t want to be wrong and sound dumb.

Also, Sram E Tap is wireless, it seems to work fine.

[aracer]

It’s likely that wires would work fine for this application as there’s always a part of a geared hub which is fixed to the frame and you could have all of this shifter mechanism attached to that with wires feeding in direct from the frame. Particularly if using a solenoid type mechanism where the moving part floats free, so could be attached to a different part of the hub.

BTW, not that I’m sure how it’s relevant, but I’d be confident that the motors used in shifters on bikes use the same technology as servos - though they will be completely custom rather than off the shelf. All that effectively means is that there’s an integrated sensor feeding back the position and the motor is powered until it reaches the correct position.

[LargeEddie]

@Superbant

I thought it was called a solenoid, but I didn’t want to be wrong and sound dumb.

A solenoid is a different thing from a stepper motor or a servo. It could be any of those things inside. I’ve got no clue, and couldn’t find any tear-down pictures to even guess from. Those two terms were the ones I saw in the product announcements and reviews. Do you know? The cycle component makers probably have actuators custom made for them, and they could well be some sort of not-fish-nor-fowl hybrid device.

Edit: Replied before I saw aracer’s comments at the top of this page. Agree about custom made and also about some kind of integrated encoder.

[aracer]

@LargeEddie

A solenoid is a different thing from a stepper motor or a servo. It could be any of those things inside.

Inside a bike electronic shifter? As I wrote before, I’m not sure of the relevance - for shifting a Schlumpf a solenoid would be ideal as one of those works well for shifting something between two positions. Not so good for multiple steps.