why don't road unis have better gearing options?

Mmm, maybe when a year’s gone by and I don’t personally know multiple people waiting on their hubs to return from lovely holidays in Liechtenstein, I’ll bite. (Again, not disparaging the hub’s designers/makers - I recognize that it’s a brand-new invention solving a difficult problem.)

With respect to maintenance, what’s this I keep reading about people having to readjust shifter buttons, and use torque wrenches to tighten things to precisely X Nm?

Let me just chime in that, since I got it back from Florian, my hub has operated flawlessly even as I’ve (as far as I can tell) punished the crap out of it. It’s making a couple funny noises now, but after around 5,000 miles on it, it still works just fine aside from the noises. My bike has given me infinitely more trouble.

I had some issues keeping my crank buttons in the cranks, and my cranks on the spindles, in the very beginning, but after about the second month, it all settled in and I literally haven’t touched it since, other than to ride it. And I just bought my first torque wrench last week, and have never used it on my unicycle. :slight_smile:

Like the good Corbin, I say a Schlumpf hub is your ticket!

And BTW, count me in for ANY reliable three-speed drive train that:
A: goes higher than 1.5
B: won’t kill me if I try to shift it while riding

Even a two-speed drivetrain with a 1.67 or 1.75 gear ratio or something (which I very distinctly remember Florian saying he could make) would be fantastic. The shifting would be a huge, intense jump, but I’m sure we could get used to it and it’d be “worth it.” I figure if we’re capable of smoothly riding as slow as 5-7mph in 1.5:1, we’d be equally capable of smoothly riding as slow as 5.8 to 8.1mph at the same cadence in 1.75:1, to shift to the same 1:1 direct drive ratio as always. Such a setup would make the flats much faster and the downhills MUCH faster, but would definitely widen that dastardly range of grades where the high gear is too hard and the low gear is too easy. That’d be a trade I’d be willing to make, though, because 165mm cranks were never more attractive than in the face of a higher gear ratio!

sorry I haven’t draw up the rest of my plans, I’ve been busy with a research paper that is now late (yet here I am, lol).

after much consideration, the disengaged/dropped cassette is more complicated a solution than required. leaving a the cassette where it is, all that is required is a derailleur that keeps proper chain tension while engaged, regardless of chain direction.

a pretty simple solution is a derailleur that pushes on both sides of the chain, which locks into place at each gear. a quick fire shifting pod for positioning the derailleur could be used in conjunction with a lever that first lifts a row of teeth that lock the derailleur into it’s position, then collapses the derailleur to allow shifting. a nice bonus is that you are would never have to freewheel, and that the momentary chain slack while shifting seems really easy to guess, as the slack is directly controlled by your lever. the derailleur cage itself is an X, with a cog on each point, that is held taught with a spring that the lever fights. the entire derailleur cage can rest on a mechanism much like the front derailleur of a bike.

To contradict what I argued earlier in this thread, on further thought I would also love a Schlumpf with a larger high gear. I am still not bothered about ‘more gears’, mainly because I haven’t seen or imagined a plausible way of building/operating them effectively (i.e. only at most as awkward as a Schlumpf shift).

A 1:1.75 gear compared to a 1:1.5 is the same proportion as 150s are to 175mm cranks. So using 175s you could get the same torque as using 150s on a current Schlumpf for a given speed, but more efficiently for your legs (assuming bikes get it right). Which, as Chuck says, would also mean you could go for 165s in the middle of that range and go both faster and easier. Bonus :slight_smile:

Sam

Tak,

Here’s the thing: These threads pop up every year, and though I’ve only been a rider/poster for three years, I have heard from other riders who have been around for a long time and they also have seen many of these posts.

There is a viable geared hub available, it has some issues which hopefully we be addressed in time. The problems with gearing unis always come down to the same issues: weight, complexity/reliability, and cost.

Unis are simple, which makes them lightweight, reliable, and inexpensive.

When you add complexity, such as a geared hub, you also add weight, decrease reliability, and increase cost.

Riding unicycles is a fringe sport, there is very little money in this sport, so R & D is also fringe. I can appreciate the OP’s intentions, but this is hardly a new idea or a new thread.

Sure, I could avoid posting to the thread, but then the OP did ask for opinions.

I will someday own a Schlumph, but it will be when I have the money to “burn” and I have a backup wheel :slight_smile:

You also asked if I am satisfied with my non geared 36er: Yeah, it’s fine, I just ride muni more often, so the 36er sits. If I had my druthers, I’d ride every day, but with a job, kids, home projects and such, I really have to pick my poison, so I ride muni 3-4x a week unless I’m skiing :slight_smile:

Don’t be such a little bitch, I can state my opinion that the OP is dreaming the dream, esp if he’s a new rider just throwing out yet another geared uni post. Nothing wrong with dreaming, but lets see some product, otherwise it’s someone’s “unsubstantiated opinion”.

My pet peeve is people who think they no someone based simply on their postings :roll_eyes:

Imagine a chain from the chain ring to a gear box above the wheel, and another chain from the gearbox down to a cog on the hub on the other side of the wheel. I would prefer belts, but this stuff is off the shelf. Now to fab a gearbox.
you will not “derail” chains with derailleurs and tensioners, so your drivetrain will be safe in both directions and while shifting, and the person is not displaced further above the wheel like on a penguin. Done.

I still reckon a multi-speed gearbox that is small, light, drives both ways in all gears, doesn’t have too much slack/backlash and is shiftable without losing drive would be pretty hard to come up with. Most bike geared hubs can only drive in one direction because they “cheat” by using roller clutches to avoid having to mesh and unmesh gears.

Single-speed jackshaft unicycles have of course been done, as I’m sure you know (Pete Perron’s are the highest-profile ones from a few years ago).

Given the gearbox would have to be bespoke, I’d suspect it would be just as costly as a Schlumpf. Somebody suggested using a NuVinci CVT gearbox on a jackshaft, but I think they asked NuVinci about driving in reverse and they suggested it wasn’t really meant to do that. And they weigh a silly amount! Although a CVT unicycle would be the holy grail of gearing systems - no nasty lurches on shifting.

Rob

assembly of jackshaft setup.

http://www.youtube.com/watch?v=kJDCuXkJfoY

http://www.youtube.com/watch?v=SQ-oxRSMlGg&feature=related

Jogi made a nice planetary geared set up too! I think the red one is Pete’s…

36geared.v1.backboxsm.jpg

Interesting idea. It will have some tradeoffs, of course, but it sounds like a plausible design. And you could have a real shifter to shift with, Sturmey-Archer style.

One nice thing about it is that it takes the gearbox out of the wheel center, so it’s not subject to drop forces like the Schlumpf. And you can service the gearbox without dismantling the wheel.

You should be able to implement it without a terrible weight penalty; gearbox+hub would probably be similar in weight to a Schlumpf, so you’d basically be adding the weight of two chains.

The biggest challenge will be managing the slop (chain slop will be added to gear slop) and devising a solid clutchless shifting mechanism. (You could also do CVT but that would add a weight penalty).

Personally I love these threads, no matter how far-fetched or impractical the idea. That this forum can provide a free space for anyone with any background to propose these kinds of ideas I think is a great service. Bringing people together from diverse backgrounds and experiences to talk about things they’re not experts in presents huge potential for innovation. Sure, most of the ideas will never see a prototype. But one day some average person will put up something that revolutionizes our sport. Well, maybe.

I find the gearbox concept very interesting. To bring some parts of ideas in this thread together: Do shaft drives take an efficiency hit compared to chains? What I’m wondering is how the play in a shaft drive compares to a chain, if slop is limiting in this setup it might be worth it?

one could pull up on the gear box to tension the chains.

Am I the only one who doesn’t care about weight so much as having a solid, reliable, multi-geared setup? I’d gladly put an extra 5-7 pounds on my uni for another two gears. Imagine: who will go faster over 100 miles of rolling terrain, a super light 15lb fixie bike with one (arguably too-high-for-the climbs) gear ratio, or a 25 lb road bike that’s stiff, responsive, and got plenty of gearing options despite its weight? Adding 10 pounds is only 5-7% off your climbing speed assuming you can get the gear ratio you want, and being stuck on a light fixie without the gears would be infinitely worse. I’d take the road bike any day of the week.

That said, I remember reading somewhere that chains become more efficient as the tension on them increases, so having some beefy chain tensioners (perhaps going in both directions?) in there really wouldn’t hurt.

Another thing that would be nice would be to have one chain on each side of the wheel: you’d add a bit of weight with the shaft(s) on either side of the gearbox reaching across the uni’s width, but it’d be well worth it as the uni would once again be more or less equally heavy on each side of the tire track. This would require longer chains to get the gearbox above/behind the wheel, behind the crown and seatpost, but I like the idea of the symmetry nonetheless. It’s just that the idea of constantly feeling like you’re riding on a cambered road (from a weirdly-weighted uni) isn’t very attractive.

Everyone aspires to be average believe it or not! I think that regardless of expert status or not, most everyone that posts here is genuinely interested and on topic. It’s a joy to talk shop with like minded folks! The general demeanor of the posters remains friendly and seems self regulated, self control is always best. I have a lot of respect for the info exchanged here and for the posters that made unicycling and related learning accessible to me in the first place.

Yes! I could even give a little on B. :wink:

Agreed!

I agree, and I’m confident that they will be addressed. I’m just saying that they haven’t yet been addressed to my satisfaction.

Yeah, I appreciate that there isn’t a ton of money being invested in unicycle gearing research.

Ad hominem, Brute? However, I made no claim of "no"ing you, just pointed out that your statement was baseless at best, and employed a tactic shared by a huge mass of ignorant trollery.

Yes! I keep bugging him to do a production run, so I can put my money where my mouth is!

+1

This is a 3 speed square taper setup that is a specific make and model. a dude bought a bunch and can mod them to work on unis. he had a CAD image of the modified guts… wish I copied his posts and not just the image…

eingangnabe2.jpg

I don’t much like the idea of chain systems and unicycles. What happens if you’re riding along and your chain breaks?.. SPLAT

Bikes can deal with that happening, uni’s… well…

the sram setup would work with an ISIS jackshaft…

That is Frank Bonsch’s project. You seem to be posting a lot of links and videos. They’re pretty but, in and of themselves, contain no real useful design information. I wish you had read his posts…don’t worry about whether or not you copied them. Frank’s hub was not a square taper axle setup. The modification that he did was extremely complicated and time consuming. The final product is a single speed hub, not a three speed hub. The square taper axle he had machined with a multi-point boss for pressing the planet cage on rather than welding it was a particularly complex part of the conversion.

You’re posting pictures of stuff that many of us have seen before and discussed in great detail. Just because there is a photo of something doesn’t mean that it was cheap or easy to do or that it is in any way practical to implement on a unicycle. It’s not strictly the case that “a dude bought a bunch and can mod them to work on unis.” I can assure you, Frank is not going to make another one of these.