Just wanted to put my 2 cents into this thread. I ride a 36" whenever I do road riding. I did a 20+ mile road trip with a buddy who rode a 29". He was super comfortable with it and had rode many long rides with it, much longer than I’ve done on my 36". We traded off for a little bit on the ride so he could try out the big wheel. He had a little trouble mounting, but otherwise liked it a lot. He bought a big wheel soon after and eventually gave away the 29". I liked the 29" fine but it still feels like a regular unicycle. The big wheel is another beast entirely.
A long bike path (multi-use asphalt or greenway) is where the 36er really excels. If you live close to a bike path, get a 36er. Once you are up on it (sans mounting woes) and get it rolling, a 36er pretty much rides itself. I agree with Harper that the OP is young. I’m glad I took up the big wheel before I got too old. I’m sure I will go smaller with age and hand them down to the kids.
True. My wife rides a b*ke and she passes me downhill but I catch her going back up. It evens out with distance.
I started on a 20, then got a 29 for my 3 mile commute and to start muni. After a while I added a 36 to my collection. I will never, ever commute on the 29 again. It was OK for it, but the 36 is waaay better, both for speed and comfort. I also like the increased visibility in traffic on the 36, both to see and be seen. However, it did take me most of a year to get really comfortable with freemounts on the 36 (but Harper is probably right about you being young and able to learn faster). The 29 is also more versatile (why I originally got it). No regrets for me, my 29er is now my muni and I love it for that, and the 36 is for commuting and cross-country/mixed surface rides.
If you’re only interested in commuting, I recommend the 36. But if you are interested in muni, then get the 29 now - AND buy a 36 when you can.
The 26 will be similar to a 29 in regards to speed. Stability shouldn’t be a problem, it will be similar to your 20. If you got dual hole cranks (150/125) you could set it up on the 125mm crank length and move along pretty good on the road, faster than jogging speed.
The workout is always there on a unicycle. If it gets too easy you can always make it harder by adding hills or going a longer way.
Off road riding is as hard as you want to make it, you start on a dirt path and take it from there.
There are a bunch of tire options for the 26" size which is nice. You could have a tire for road riding and a tire for Muni. If you spend a lot of time on the road, which it sounds like you will, a road tire will make it a much nicer ride.
Its a nice uni
But a 24" youll not get much more pace
Or you’ll still have to pedal uncomfortably quick
A 26 is better still
But as the wheel size increases you’ll find a place where your going at a reasonable speed with a reasonable pedal speed. For me on my commute I find 26" too small a wheel
You may be very comfortable with it
As far as how hard is muni
Don’t build your impression of off road unicycling by watching videos of Kris holm balancing on the edge of 1000’ drops, or uni geezer going down these crazy rocky paths. Get out and do some
Start easy on bridle paths walking trail. Ride on some gravel and packed dirt. It doesn’t have to be extreme or dangerous to be fun
From reading your original post I think you’ll love the nimbus 29
I don’t have a 36 (yet). More a space issue than anything else. So I can’t comment on these
But a 29 is fun off road and usable on road
I had a 26 guni wheel in my 29 frame for a while. The 26 is definitely slower and less comfortable than the 29.
For me at least, 29 is minimal size for any non-technical riding.
Also, there is no reason not to start muni on a 29; for the easier trails you’ll start on, a 29 is more fun and can actually be easier because the larger wheel radius smoothes out the bumps.
Another reason why a 36er, or at least a 29er, would be good for you:
You can emphasize to your boyfriend that your wheel is bigger than his!
Also, casual rides with a bicyclist are a possibility with a 36, but not really for any smaller uni.
You will be able to adjust more quickly to a smaller wheel than going straight to a 36. However, when I went from 20 to 29 for commuting, it made less difference than I had hoped. Going from 29 to 36 actually made commuting a reasonable prospect for me. When I first got my 36, I felt like I had wasted my money on the 29. But then I got into muni with the 29, and I’m now very pleased to have both.
36 would be best for your commute, no question about it. And that includes the lowest level cheapest 36. But it would take a pretty high level of commitment and work to get comfortable on it, and there is the storage issue. A 29 will take minimially more effort to get used to than the 26, would be significantly better for commuting than anything smaller, and doesn’t really take any more storage room than a 26.
It seems like your first instinct was a 29, and first instincts are also worth paying attention to.