As a few members may recall, I had the honor of testing Greg Harper’s Der Uber Coker, which had an internal hub that was not shiftable on the fly, but you could manually change gears fairly easily. Riding that unicycle was one of the highlights of my one-wheeled life, and of course sparked my desire for the commercially available Schlumpf hub. With Der Uber Coker, I never had to worry about inadvertently hitting a shift button. And while I firmly believe that an internally geared hub that is shiftable on the fly offers many exciting, new opportunities in the world of unicycling, I also think that there may be times when some people would prefer to just ride their Schlumpf-hub unicycle in high gear and not even bother to do any down shifting. It is for these times that my invention (if viable) might come in handy. So what is my invention? It is a simple 3D-printed plastic safety cap that installs over and around the gear shift button(s) and prevents the rider from accidentally hitting the gear shift button. Would this work? Would anyone use such a device? I am very much looking forward to doing lots of shifting on my Schlumpf 36er once it is built, however, there are still times when I think I would like to just ride it in high gear without any concern about hitting the shift button when I don’t intend to, but being that I have never ridden a unicycle with a Schlumpf hub, perhaps my concerns are unwarranted? I’d be curious to hear what you think about this simple safety product idea.
I’m pretty sure you can just take the buttons off to avoid accidental shifts, rather than covering the buttons? I think they unscrew?
The shift buttons are a very similar width to the inside circle of the the crank extractor threads, so I can’t see anything plastic fitting down the sides and screwing in tight there. Maybe the alternative would be to have either the buttons, or your new 3D printed caps which screw into the extractor threads like dust protectors on old cotterless cranks. You could use the buttons to position the hub in either High or low gear, then remove them, then have two threaded caps of two different thicknesses /depths. The thinner one would screw onto the side where the shifting rod is sticking out further, and the thicker one onto the side where the shifting rod is further in, so that (if the depths were carefully planned) the shifting rod would be unable to shift accidentally from its current position. I guess the caps would have to screw in until they were tight with the bottom of the crank threadnto ensure they wouldn’t unscrew accidentally while riding
It needn’t be something that screws into the crank like the cotterless dust protectors – it could be something that clips (or slips) over the cranks. That might be a bit more challenging for an external disc crank but I’m sure something would be possible.
I don’t have a Schlumpf but it seems like a good idea. They could also be used to protect the shift buttons/mechanism during transit.
I am shooting for a simple product that does not involve having to remove the buttons.
I thought about this approach, if a universal product isn’t possible. If a product that fits all Schlumpf hubs without adversely affecting the hub in any way were possible, I would be highly motivated to create that product and make the 3D files available to whoever wanted to print out their own gear shift button protectors. Once I get my geared 36er, I may consider designing a version that fits around and over the button and part of the crank.
Thanks!
That’s very true! I hadn’t thought 
about that, but that sounds like it would be another good use for them.
I’m not really convinced by the idea. When would you like to ride only in high gear? That would mean you’d have to start in high gear, which is quite challenging. Plus, you would have to achieve every single hill in high gear. Unless you leave in the Netherlands, I’m not sure that doable…
I have a similar concern for riding only in low gear. Why would you use a 1.5 kg hub if you never make use of its unique ability to shift?
IMHO, being able to shift on the fly is what makes Schlumpf hubs really useful and I can’t see the use of intentionally removing this ability.
Living in The Netherlands is surely doable 
Though I once bought a schlumpf on a KH 26" muni and I just couldn’t figure out the high gear. As soon as I shifted I tumbled off and riding away in high gear didn’t make it any easier. I ended up selling it again.
But as an answer to my interest to have a cap over the gear-shift button, I think that is silly. Being able to shift is the whole point of the hub.
For some events, when gearing was forbidden, I screwed the up shifting button further in, until it bottomed out.
Don’t you have other non-geared unicycles for such events? I imagine you’re way more professional than me and prolly have a big collection of uni’s yourself 
While I don’t like to find fault with other’s ideas, I have to say, the only “accidental” shifts I’ve had were during a upd, when my foot accidentally hit the button during the process. So I personally would not likely be a candidate for using this product. Others might! 
Don’t stop thinking up new things! 
Haha, you missjudge my level of professionalism and my collection of unicycles. I only ever had two “outdoor unicycles”. My old steel 24" Muni that I later added a disc brake to and my 27.5" Schlumpf Muni. Both are around the same weight and the 24" was reasonably slower. When having the chance, I alway chose the bigger one for races. Choosing the other one would not have had an advantage.
That said, I’ve almost all the parts together for a really light 27.5" Muni that I’m hoping to build within the next weeks. The 24" is already abandined and dismantled. The saddle is sold and the frame will end up as my truing stand.
It’s not for everyone. There are plenty of times when I’m riding on relatively flat bike paths, or in other areas that are relatively flat (outside of the Netherlands) and don’t have a lot of people, cars or other things that get in my way much. On these types of rides, I might like to just cruise in high gear. I’m used to riding this way because it’s the only form of geared unicycle riding I’ve ever done. It was prior to Schlumpf hubs being available.
Of course, being able to shift on the fly is an extremely exciting and awesome technological development for unicycles. It is something that I am looking forward to tremendously and plan to utilize constantly. But that doesn’t mean that there still wouldn’t be times when I’d like to pop on my gear protector and cruise in high gear with no worries. I have no issues whatsoever mounting in high gear. It is something I can do consistently and I actually find it to be a lot of fun.
Also, for me personally, I tend to press the inside of my foot and leg against the crank when I bank sharp turns. Having the cap would ease any concerns about inadvertently pressing the gear shift button. Also, I would just consider it a general safety feature when I’m riding a lot in high gear in a hectic environment like Manhattan, NYC. Realistically, when I’m cruising in high gear, I don’t think I’d be able to use downshifting in many (or perhaps any) emergency situations in the city, thus if something gets in my way, my only two options (other than bailing) are (1) if I have sufficient distance (and have mastered the quick stop technique of shifting the frame aft as I apply brake pressure), then I can attempt to brake to a stop or brake to slow down a bit, then return to vertical and hang a turn, or (2) if there’s no time for braking, an evasive maneuver is my only option. In situations like this, I might feel better knowing that I won’t be able to activate the gear shift button accidentally when I throw the unicycle into a turn. And if I want to go back to more mellow riding, such a protector is easy to pop off and on, since it’s a simple, removable product.
If you have no intention to upshift, there is no good reason I can see to be riding a unicycle with a Schlumpf hub, so that is not a scenario that I took into consideration.
That’s why the protectors are designed to be a removable product that can quickly and easily be installed and taken off. It may not be a product that is desired or needed by you (or most people), but for my situation and the riding I will be doing in the urban jungle, I think it would give me some peace of mind. Thanks for your input. It is much appreciated.
Interesting! Sounds like that’s a way to essentially keep it locked in high gear. If and when I have the confidence to know that I can easily adjust the buttons perfectly for shifting, that may be an option for me. Thanks for letting me know!
I actually value hearing about the faults with my ideas, but I relate to where you’re coming from and I have taken the same approach sometimes. However, honest feedback (good and bad) helps me design better products (or perhaps decide not to design them at all), so it is most welcome. It is well within the realm of possibilities (or perhaps quite likely) that most riders, like yourself (and possibly even myself, if accidental shifts aren’t really much of an issue) wouldn’t be a candidate for using this product. Thank you very much for your feedback and encouragement. I very much appreciate it.
You really are a Hardcore Coker Rider 
Do people even see you coming? 
Thanks! I hope I still live up to my moniker. I found an amateur video guy who said he will record some of my riding, so I am hoping to put out a “20 Years Later” video, or something along those lines, if and once I surpass my level of riding in my first video. If somehow I can’t pull it off, then I am no longer deserving of the moniker and I will have to come up with another name.
I haven’t ridden a geared unicycle in about 20 years, but when I did ride it I distinctly recall people having a very confused look on their face. Since the gearing is internal and not visible, I think they were puzzled as to how I was passing up a decent number of cyclists and travelling at a speed that must have seemed rather strange to them. Many New Yorkers saw me coming, but there were also plenty who did not. If you’ve ever been to NYC, you’ve probably realized that lots of people are just in their own world and not paying close attention to what’s going on around them. That is probably a contributing factor in some percentage of the fairly high number of pedestrian injuries and fatalities that occur every year in this city as a result of car and truck strikes. I would suspect the same is true to some extent or another in many other cities, as well.
Sounds to me like a G29 (or G32) would be a better idea for this application… Sure, not quite as fast, but quicker to accelerate and decelerate and way more maneuvrable (the heavy rim will be quite a pain in that regard).
As far as your original question, I could absolutely see a cap that screws over the button that doesn’t stick out. Just checked on my G29, and there seems to be enough threads that a cap could hold onto, despite my shift buttons extending farther out than recommended[1].
For fear of accidentally shifting I decided to go with curved cranks. Unfortunately they are curved so strongly that I now have a hard time to shift at all, so I changed the location of the buttons. IIRC it’s recommended for them to stick out about 2mm, mine stick out probably double that. So, yeah, curved cranks could also be an option, but in my opinion no really when combined with a 125mm hub - that would end up reaaally wide ↩︎
The heavy rim is for my standard 36er (that I will use mostly for skatepark riding), not my geared 36er. My geared 36er will have the aluminum rim.
Wow, that is great news! In that case, at some point I will probably get around to designing and printing out some gear shift button protectors. While most people may not feel any need for such a product, I will be happy to share the CAD file or print out some protector caps for anyone who would like to try them out. Thanks for the information!
On a unicycle equipped with a Schlumpf hub, there are two things to avoid more than on other unicycles: unintentionally riding on one foot and unintentionally downshifting. Both lead to falls.
For me, the solution lies in the shoe/pedal contact. I found a solution in clipless cycling shoes, and today, I find the best option to be magnetic pedals. Getting on and off the unicycle is easier than with mechanical clipless pedals.
Rather than locking the gear shifter on the Schlumpf, I think it’s better to lock the foot.
That’s great that you found a solution that works well for you! For me, locking the foot would not be preferable because I often change my foot position when I’m riding. Getting on and off is not problem, so that’s not a factor. Plus, I like riding in the shoes of my choice, particularly sneakers that have good support and cushioning.
Pictures
Out (as explained, I adjusted the knobs to stand exceptionally far out):
In:
In, different angle:
So you only need one ‘plug’ that you can screw into the crank on the side that is pushed in.
The other side doesn’t need anything as the button can’t get pushed in because the plug at the other side means the shifter rod can’t get pushed through.
3d printing the thread might be a bit challenging, but one of the cotterless crank dust covers might work as is.