I’m looking for a new uni for transportation in a downtown area with a lot of stop-and-go. Id be grateful for opinions on whats the best wheel size, which is to say the largest size that is practical for that kind of riding. TIA
Depends on your distances, but I like a 29er with 110mm cranks for getting around the city. Very flexible for getting on transit or in a car, maneuverable enough, idleable. For distances up to about 5km I think that’s ideal. Longer than that and the 29er starts to get boring to ride.
Some people use a 36 but it’s a lot more ungainly.
Like tholub said it really depends on how much distance you plan to ride if it’s 1-2K’s a 24" would be ideal. I was travelling around Australia last year with a 20" ALDI uni and since I was still learning it was great I just pulled it out any place we stopped went for a quick ride and threw it back in the car. Later I went south into NSW/VIC and I bought a 24" Nimbus II specifically for that trip and it was just the perfect size to fit in the boot of a car and to get around small towns quicker. Was also great for getting around the twelve apostles park quicker then walking.
When I didn’t have a handle bar on my 29/36 they fit in the back of my hatchback without having to put the seats down. As for taking them on public transport I would think 29+ would be a little too big. Something smaller then 29 would be the way to go as you can take them into places and people generally don’t mind and then you don’t have to worry about locking them up.
Depending on your confidence with freemounting, 29 is generally the most practical all round size. A dismount or mount takes very little time or energy, and is less likely to be affected by traffic, pedestrians etc.
I commuted for a few months and tried every uni in my fleet (20, 24, 24 muni, 28, 29 and 36) and found the 29 the least stressful.
Fpr comparison, except when tired or on difficult terrain, my freemount percentage on the 36 is as near as dammit 100%, I can idle it for short periods, and I can ride for well over an hour without a dismount, including hills, rough ground etc.
However, I’d still choose the 29 for the circumstances you’ve described.
I agree with Tom about 29"; probably the biggest wheel you’d want to be stopping and going with, though it’s still a little on the large size. And 110 cranks are good, though if you don’t feel confident, start with a longer size and work your way down as you build confidence.
Smaller wheels can also work if your distance isn’t too far.
I quite liked riding a 26 with 110mm cranks as a general around town ride. A skinny 28 with 102s was also fun but not as good in the stopping department, but damn it was agile. I’m sure 29 would be fine if you are used to the size but I wouldn’t want to deal with pedestrians in tight confines with a larger uni like a 32 or 36 (been there, done that, not as much fun).
I don’t have a 29. But do have 26 and 32. I would never want to manuever around pedestrians on a 32. But I can and do work around people on a 26" with a 3" tire very easily (after a couple years). I wonder what the 26x3 diameter would measure. probably a little smaller than a 29 " skinny…?
I’ll add a vote for a 26". Never ridden a 27.5" but it might be similar. I think 29" is a bit on the heavy side and less urban friendly.
But… I’m also someone who happily rides 10km plus in urban spaces on a 24".
I think a 26" with shorter cranks (I normally use 100mm) is pretty nice to be honest. Easy to mount, easy to go slow when needed but possible to maintain a nice little cruising pace if you want. You certainly won’t be the fastest thing around but a lot faster than walking and even jogging, while being more fun and less effort. Also small enough to take on crowded public transport for mixed-mode commuting (just stand and hold it in front of you).
Of course a 24, 27.5 and 29 could all work too, and will have their strengths depending on how crowded and chaotic it is but with the little information you have given, 26 would get my vote. It is worth remembering that every uni size involves compromises.
Here is my Nimbus 26” with a Duro “Beach Bum” 26x3.0/70-559, next to my Schwalbe “Marathon” 28x1½/40-635 wheeled Pashley:
Here is my Nimbus 26” with an Innova “City Tire” 26x3.0/76-559, next to UniMyra’s spare QU-AX 29” (29X2.1/54-622):
Let’s try this by your height…
Sub 5’6" = 24"-26"
5’6"-6’ = 27 1/2"
6’ plus = 29"
For a skilled unicyclist that can freemount and ride slowly I would go to a 32" for under 6’ and 36" for over 6’.
Let’s see how this applies.
I’d say depends on the distance. But also depends on the type of city you live in.
I see a lot of my fellow europeans advising on a small-ish wheel. Which totally makes sense in our small cities with crowded sidewalks, small streets, not many straight fast tracks. If that’s the case, then yes, up to 29" would work.
But if MCzonie lives in the US in a big city, then I wouldn’t go for such a small wheel. I’d start at 29", with 110mm cranks if skilled (125mm if less confident), or go straight to 32", the last size that can easily be freemounted (if you’re in the 6ft tall region) without having to do a run mount/jump mount.
I am with those recommending the 29. I have been riding a 36 the past year, but haven’t gotten much ride time in the last few months. I live in a very hilly area (typical ride is at least 75 feet of elevation per mile, sometimes in the 100 feet per mile range) so starting riding again when my fitness is low is very tough with the 36.
I got a 29 for Christmas and I have ridden that for 4 rides a week for the past few weeks. Yesterday, I decided to ride the 36 on the same 9 mile loop that I have been riding. Besides being more difficult uphills, what really stood out was how ungainly and heavy the 36 felt compared to the 29. It is another level or 2 more difficult to ride and mount.
The loop I use has about 6 places that I need to cross at a light. Most of the time I prefer to stop and walk across for safety reasons. It was a lot easier with the 29.
That said, if you consistently ride the 36 or 32, it will get easier in all ways as you gain skill and fitness. Probably depends are where you are starting from skill and fitness wise. They will always be more ungainly, but your skills will improve.
The only advantage in my mind to the larger wheels is ability to go faster at lower cadence. 36 is theoretically a 20-24% faster uni to a 29 depending on tire size on the 29.
If I had to choose at my current level, I would choose the 29. As I get better the 36.
*note: the loop on the 36 for me is about a 9.5 on the “how hard was that” scale. The 29 is a 7. I am barely completing the loop on the 36. If I kept riding the 36, the difficulty rating would move down to probably about an 8 in a month’s time of consistent riding.
Here is my 36 ride on Strava:
https://www.strava.com/activities/2991615603
Here is a similar loop on the 29:
https://www.strava.com/activities/2982597320
Note that the average speeds are not that different for me. 5.7 to 6.4 (29 to 36). I’m not a particularly fast rider at this point (10 mph on the 36 on the flats) and the hills really slow down the average.
The 29" is a good choice, but anymore I like to get around downtown Sacramento on my 36. As long as I’m not worried about lots of pedestrians, its just quicker and more fun. Also, more compatible with the bike lanes.
Other advantages are: you’ll get a lot better a freemounting; and you’ll also get better at hopping or still-standing at stoplights.
I know tholub is an amazing rider. I wonder, though, how many average riders could manage a 29/110 setup, not to mention in an urban setup with lots of potential obstacles. I may not be qualified to comment, never having ridden on cranks as short as 110mm, but it seems that you have to be well-balanced and able to ride in a very controlled fashion to manage with the above setup.
A 29/110 setup will give you a good cadence/speed, but you would need to be an expert with a brake to stop suddenly without crashing or UPDing. If you ride in a busy environment with this setup and run into something, it’s your fault…for riding when you should have walked the uni across the street and for picking a fast and hard-to-stop setup.
tholub mentioned being able to idle on this setup. I would like to know how many riders on this forum can monitor the 360 degree space around them while idling. My point is that it is not nearly as safe as getting off the unicycle. I can only imagine, too, that the sight of a unicyclist idling must be confusing to drivers.
I don’t know anything about the riding ability of the OP. At the very least, the urban 29/110 setup seems like something you’d have to work towards.
I am not an amazing rider. Far from it! In fact my skillset is pretty much limited to mounting and riding. I ride twice daily but still… it seems that a lot of you have a much wider skill range.
I regularly ride a 26 with a 3 inch tyre and 100mm cranks, with ice and (light) snow in an urban environment, and I have no brake. If you scroll back to my earlier posts in this thread, I include pictures that show how close in diameter a 26x3 is to a typical 28" and 29" setup.
In the summer months I also experimented with UniMyra’s spare 29" and 100mm cranks, and for a short while, with my 26x3 running 90mm cranks. My primary issue with 90mm cranks was that the hills in Oslo felt just a little too hard and hence the average speed on my commute was slower than when I use 100mm but I didn’t feel unsafe.
With respect, I think you are overestimating the difficulty of controlling wheels in this size range with such short cranks. Certainly I have more fine control with wheels in this size range and 100mm cranks, than with my 36" and 125mm, which is actually my most regular choice into the city. Granted I don’t go right into the very heart of Oslo, which is why I use the 36er. If I did, then I would be more likely to use one of the smaller wheels (26/29) with 100mm cranks.
My 26, even with a 3 inch (road) tyre, carries nothing like the momentum of my 36 and it is far easier to turn sharply or drop off the back at speed. It is also still much easier to cycle at a very slow (walking) pace, which I occasionally have done around pedestrians. Plus I have the confidence that when slowly dismounting in a crowded environment it does not shoot forward nearly so much and hence is much less likely to hit someone.
True but I really don’t think it is that much work, in the grand scheme of things.
P.S. You should try some shorter cranks if you do road riding! 
I ride a KH29/117 most places, but I don’t think it would be sensible, or fun, to commute. More so 29/110, which BTW will be my next crank set. I have enough saddle time to handle the footpaths and people with the 29/117, but why? Each unexpected stop is that much harder and a potential collision. Mounting is more cumbersome, even if you are a legend. Idling, hopping and stop/start are all less reliable. Sure, take a 29 commuting, but consider the terrain and the other people around (even if they do not consider you, like on today’s ride 
)
@BruceC To be honest your reply is a surprise to me if you use a setup like this regularly. Not least the comment about mounting. Sure shorter cranks mean it is more of a step up but you also get the advantage of less movement due to the higher gearing. You can can put down much more pressure and almost step onto short cranks on a wheelset of this size, while longer cranks would cause the wheel to want to move towards you. For this reason I find mounting with short cranks easier if anything, at least for a static mount.
Well lucky you @ruari!
I really prefer shorter cranks, and 29/117 is my preferred unicycle with many 1000’s of km in that configuration and looking to go shorter. I’ve also been riding my 36 almost exclusively now for 2 months to try and improve my handling of this big, heavy beast, and am currently moving to a shorter crank, so now the 36" static mounting sucks.
For me, perhaps not you, it’s not the mount. As you say is easier as the wheel is less likely to move back on you. It is the move off afterwards where the failures occur. The shorter cranks mean pushing much harder and for me that means less subtlety in control. Hence the “mounting” issues.
In regards to the thread’s topic, it’s also about maneuvering, slowing and stopping in crowded areas. I almost ran over an un-leashed dog today and only just stopped the 36" in time, in part due to trying to stop a wheel with shorter cranks. For a better rider this may not have been an issue. But the physics, unlike dogs and kids, is predicable.
I love riding my 29" and can easily do 20kms with it. It is versatile for both road and off-road. I ride with 150mm cranks btw and have used it a few times for commuting, as well as a 26" and 32".
As for McZonies initial question to me the 26" would be much more a stop-and-go uni than the 29". Smaller wheels mount more easily and a bigger wheel is only nice if you can also make some real distance.
If you’d have to navigate around people, then to me shorter cranks introduce less control.
Lately I’ve been riding the 32" more, because I intend to parttake in the Dutch Championships again with the same setup as last year. I ride with 140mm cranks and a T-bar. I wouldn’t take the 32" on the pavement with lots of turning.