Actually the other way around, I ride more Muni than Road.
The crank length for Muni really does depend on the terrain you are riding it on. I ride on the North Yorkshire moors and they have a mixture of quite long steep inclines and gentle open tracks. Mud/sandstone and roots. For me I am comfortable with 150s for that and… I have been using 150s for Muni for almost 40 years and I guess I am just used to them now!
My advice is ride what is comfortable for your riding style and environment.
36"
Good point! When dismounting you push the 36er away from you, i.e. smashing it against the door you were stopping at. In that case I keep the brake pulled and let my body being pushed away from the door instead. But when there is not enough space around you, it generates brute force and makes it fit.
Yep, was once in a similar situation (albeit on a 29er). Crowd of pedestrians, me following a group, waiting for a (forseeable) occasion to pass them. Meanwhile the gap behind me closed and people were closing up. At some point I realised that if I had to dismount - be it planned or not - that would hurt someone in front or behind me. Simply because the uni has to move either way for me to dismount. Fortunately that situation persisted only a few seconds, as the people in front of me passed the obstacle that forced me to stay behind them in the first place, and I could finally overtake them.
Why does everybody always want to ride fast. I like to feel the sway of the unicycle. I never ride to go places. I ride for an hour or 90 minutes to just to enjoy the ride.
If I want to work out, I can go to the gym, but that is just boring. That is why I have nothing against riding 10km on a trials unicycle. It is just fun to do. Same as with a UW where Im broken after riding 100 metres, but making it that far keeps me happy all day.
Riding that slow is very difficult I think. Sometimes I try to go as slow as I can as that is one of the things you can do at the unicycle championships, but I will always go too fast or I lose my balance and for that reason too I don’t riding in a crowd.
I used to think the same way. But I must admit, when I‘m using the 36er or the G29, I do indeed enjoy that feeling of speed (and I‘m still very slow compared to others). When you start to feel the airflow …that‘s kinda cool.
I think it is difficult to hang enough forwards to be able to spin very fast while at the same time keeping your balance. And yes I tried with shorter cranks at some time, but in the end I preferred the relax riding more.
Seeing those 100 metres sprints with 24" uni’s is cool to see though.
Here these dudes are really fast. Not sure what cranks they have, but also very narrow tires.
The closer you ride to your max speed, the smaller your safety margin becomes. I know this out of experience 
f-spin: 
f-spin:
I think it looks as silly as impressive.
If I remember correctly I maxed out at around 160rpm with shortish cranks (100mm on a 20“). But in everyday riding I didn‘t see much benefit of the shorter cranks, compared to the longer ones I used before (114mm). But I did suffer from the loss of control that came with the shorter cranks. So I accepted for now the fact that I’m not a quick spinner* and mounted the longer ones again. Maybe I will try shorter cranks again some day. On the 36/140 my max speed is around 24km/h, on the G29/150 it‘s around 25km/h. So, yes, there are way faster people around, both geared and ungeared. But I‘m not racing against them, I‘m just trying to have fun without crashing.
*which shouldn‘t be a surprise, given my modest max speed when running…
I wouldn’t ride 24 kph. It is not possible to run out of that should you UPD.
Correct, that‘s why I always wear a helmet, gloves, knee and elbow protectors and (if I don‘t forget them) crash pants when I intend to ride fast. My limit of outrunning a UPD must be in the range of 13 to 15kmh…
The protectors take away some of the fun; I can‘t just casually grab the uni and ride wherever I want anymore. It takes time to prepare myself for the ride, and it‘s less comfy. But the prospect to increase the chances of surviving a fall without annoying injuries makes up for that, in the end.
Fast is actually not my goal, but far. Far enough to get to the actually interesting places to ride within reasonable time. Leaving me time to do some actual Muni for example, and not just double back and go home again.
I don’t have a car and public transpost is often such hassle (also why take the bus if I can ride instead? The time is often quite comparable anyways). Faster = Further = More fun and variation.
yeah ok. I always drive to where I want to ride and can stuff 3-4 uni’s in the car, so last minute can change my mind what Im gonna do. Kinda what I blame my wife for doing when she changes her plans continuously.
I agree with you about restricting your speed to what you can cope with as a UPD… but I ignore that advice and even at the speeds you have mentioned it is hard to get your feet on the ground running. I ride a little faster than you and although I don’t fall much, when I do I end up with a run/fall/roll that often leaves me with some grazes, but I have not broken anything for 20 years.
When I was younger I could do 40kph (25mph) without gearbox and 38Kph with gearbox. Luckily I only feel a few times at that kind of speed and yes, I did break things.
I want to be able to keep up with my wife on a 2-wheeler (since she won’t move to a uni); and I want to be able to go farther in a single day.
If I’m not doing either of those, I’m not concerned with speed. Having fun in the cul-de-sac? 20. Pleasant jaunt through the city? 24. Yesterday’s trip to the local farmer’s market? 26. The trail ride I need to get off the couch for right now? g29.
Often times it was a good training to ride that slowly in 2nd gear. Estimated 12-15kph was the family speed.
My dad wants to go on bike rides with me, but I am opposed to riding a two wheeler. This is my main motivation to get a distance uni, though I’m still worried that I won’t be able to keep up with his 2 29" wheels with my 1 29" wheel. I am planning on getting 125mm cranks for it, though I fear then I won’t be nearly fast enough. What should I do?
You might want to look at multi- length cranks.
I’ve got VCX+ cranks on my g29, and usually ride them at 125mm. I can hold 10.5 mph (16.5 km/h) for about an hour under ideal conditions at 125mm.
This is a lot of guesswork based on my experience on a 26" bike - it’s possible your dad would going about 15-19 mph (24-30 km/h) on a 29" bike when he’s in the zone, and if he’s riding more leisurely he might be riding about 12-13 (19-21).
I’d probably move my cranks down to 100mm for a ride with him. I might get 11 (17.5) - 12 (19). That might work for you. I could make it work for me and my wife, if she really slows down and I really push hard.
I don’t love that combination and that’s exactly why I bought the schlumpf. My longest high gear runs have been around 11 mph with a very relaxed cadence, and I hope as I get more comfortable with the high gear I’ll push it up to 12/13 and fall right in line with my wife. (Math obviously says if I can push 10 in low gear I should be able to push 15 in high, and if my normal runs are around 8.5 I should be hitting 12-13.) But that’s an expensive way to get the speed. Shorter cranks are a lot cheaper…
My neighbor is a bike shop guy, he has a workplace set up in his garage with tools and everything. He’s also very nice and has helped with my uni before. I’m hoping he can help me drill holes in my cranks, then maybe I could go faster. I have 114mm cranks on my 20er, and I want to make 70-90mm holes there. And when I get the 29" with 125mm, maybe I can put in more holes to go faster, but I want to get used to the 29" with more control at first.
Any idea what your cadence on the 20“ is, when you push a bit?
That could give you a ball park of the speed that can be expected on a bigger wheel (the real speed will probably be slower since you intend to mount longer cranks than on the 20er).
It kind of depends on how fast your dad rides and what you mean by keep up. If he’s a serious cyclist then without a geared uni (Schlumpf) you have little chance of sustaining 30kph. A “casual” cyclist usually rides more like 22-26kph. That’s still crazy fast for an ungeared 29" (I usually don’t ride that fast on my ungeared 36").
But if you mean taking a leisurely trip to the park or the lake, then it can work. I often ride my ungeared 36 with 125mm with my family on bikes for local 2-15km rides and they only occasionally have to wait on me (say 20-22kph with 125mm cranks). I also do longer mountainous tours with strong mountain bikers on my 29" muni and it mostly works as long as there are no longer flat or open downhill roads (I max about 22kph and downhill they can coast at 35+).
I would say a 29" with sub-125 cranks should probably work if your dad isn’t interested in going really fast all the time and willing to wait on you occasionally. And as you’ve correctly stated, you will have to work up to this, as you won’t be able push short cranks from day 1 and it will take some time.