I was actually working on this for a while. It’s actually not as difficult as you might think, I just worry about the longevity of the design. Maybe I’ll dig it up again.
Quick release bearing cap, adaptable to unicycles with with Nimbus/Torker/KH/K1 styled bearing holders. This way you could change wheels and only run one frame (20/24, 24/26, 26/29).
Brake bosses located on opposite sides of the frame so you can spin the frame, change the wheel, and move the brakes, and you have one frame for two wheel sizes. My Ti frame is going to be designed liked this 
A molded/formed aluminum seat base with integrate seat post mount (Thompson or KH), and an aluminum grab handle, all to minimize flex and improve resistance to breakage. Lightweight and strong, though certainly more expensive than a nylon seat base.
A Ti frame, got that one in the works already!
I got one in the works…
1 Like
Seat
I wish someone would invent a better seat. There have been some improvements on the margins…but a real revolutionary improvement in seat technology would be nice. A seat you could be in comfortably for hours.
Carey
2 Likes
I have never tried the 2 holed KH cranks, yet I know that for me they wouldn’t work. I am to meticulous mechanically, and have to clean the threads and grease them when I install pedals. The idea that I would look at a hill and then pull over and do a pedal installation , is just to mechanical for me. I know how to do pedal installations, and that’s why I don’t want to do it when I am riding.
Riding is all about having fun and not working on stuff.
W bear’s fantasy of a fast adjustable crank and seat might be achieved most practically with a set of slotted, notched or grooved, cranks that could be moved fast to a different slot using an Allan wrench, same size, one would hope, that you would need to adjust the seat.
I’m sorry I don’t know how to post a drawing. The idea is cranks that instead of having to remove and reinstall the pedal, an Allan wrench could go behind the pedal, spin 5 times, slide the “pedal carrier” (a thing the pedal threads into), that moves in a notched slot in the crank , and slide it into a new position and tighten it up, in < 15 seconds. Then use the same wrench to adjust your seat. Fast, and it doesn’t mess with my “clean parts with grease” compulsion. Seriously, the idea of grinding a greased pedal into the dirt packed threads of the other hole, at the side of the road, is disturbing to me. 
I’ve been putting some thought in to this over the last few months, and have come up with two ways of doing things. One is simpler and lighter (but probably not strong enough), and the other is stronger, but heavier. Both, however, would have a little motor inside that slowly adjusts the crank length based on the speed the cranks are turning.
So, for example, when you mount, they’ll be at the maximum length (maybe 150mm), and as you go faster, they gradually shorten. If you was to start going up a hill, you will naturally slow the cadence down, thus they lengthen making the hill easier. Likewise, as you start to speed up down the other side, they’ll shorten again.
All I need is a small suitcase full of used notes, a friendly machinist and a helpful electronics engineer and I’ll get some test ones built up.
STM
How about covering the holes you’re not using with plugs or tape to keep the dirt off? Then they could have some lovely clean grease inside them and you can store the plugs in the other holes you’re not now using.
Business opportunity for UDC/KH or wherever to supply threaded plugs. Just remember my commission;)
Designs I’ve been playing with sound similar, but use spring clips to hold the pedals in their various positions.
It appears that I’ve been thinking about this for more than a couple of months. I just found this post I did over 2 years ago;
http://www.unicyclist.com/forums/showpost.php?p=809947&postcount=1
STM
Hmmm. . .if you build it out of carbon fiber, it could be lighter than a standard wheel, and then it would eliminate basically all of the major issues with the 36" wheelsize.
'Course then you’d have a fragile carbon wheel. . .
For the adjustable length crank with max strength - and fewer moving parts, how about a round disk in the end of the crank with an off-center pedal thread. As the disk is rotated, it moves the pedal away from / closer to the hub? It would need to be locked in place with a set screw at predefined, notched positions.
I haven’t come up with a reasonable way to securely fasten / embed the disk in there yet.
I tried moving pedals from one hole to the other on my on last ride and cringed as the dirt was grinding into the threads. I was thinking to try some of those foam earplugs - but not sure if they’re big enough.
I’ll need something to keep them clean.
they make plugs for them… i had some on a bike a while back…
I’d like a big flag that says: HERE COMES THE CLOWN. (I’d probably give it to Harper).
i would like a leotard that matches, to give to harper as well.
Wow, 4umfreaks link shows the real answer
Hopefully you don’t have to buy 2 pairs just to get 2 receivers, but that looks to be a must for anyone who uses dual hole cranks. It looks to be as fast and easy as changing an air tool.
That’s interesting. Although the pedals themselves don’t look very grippy. But the system could be used for something more suitable for muni.
leaving a second, unused receiver in would be a nightmare - if you’re lucky and it doesn’t get in the way of the pedal, then it would get in the way of your foot unless you only used the outer edge.
Nice idea, but destined to be a failure: unless you have modified, flush receivers and custom cranks to fit (the hole would need to be oversized for enough strength of the male/female connection)
That’s why I suggested it to be “built-in”. If the collar bit is internal to the crank and the pedal is held in place with a user removable split-pin of sorts that is pushed through the crank.
We already have custom cranks, with two sets of holes - that’s not the issue.
Give me multi-hole cranks with mated pedals that I can swap without tools and we may have something.
-M