Thanks. Looking on line I saw the brake systems, and figured the ISIS would be best too and kind of had my eye on the 27.5" Nimbus Green Monster . Are the brakes hard to get use too and that helpful if not going down that many hills? What would you recommend for over $400?
The differences are smaller than you think. 29" is only 11% more than 26".
If you cruise at around 8 mph, that translates into less than 1mph difference.
The difference in height is related to the radius which is only half the diameter. That means the 29er seat is about 1.5 inches further off the ground than the 26er seat.
Dual hole cranks with 150/125 or similar are a good option. I’ve tried most sizes from about 90mm to 170mm over the years and have stabilised at 150 for optimal torque or 125 for versatility.
You can’t go wrong with a 29 from any of the main manufacturers. All my current main unis are KH, but I’ve been happy with Nimbuses in the past. Neither will let you down.
I’ve owned all the main sizes from 20 to 36. I’m 56 years old. I find the 29 is the most versatile all round uni for on and off road.
If I want to ride anything rough, I step right down to 24", and if I want to go far and fast, I step right up to 36. I sold my 26 as it did not add anything to my options.
Realistically, you will have as much fun, more or less as much speed, and as much versatility, on a 26 as on a 29 or a 27.5 once you’ve found the optimal crank length.
Weight, storage space, and tyre availability may be more important considerations.
Caveat: all tyre sizes are nominal, so a 29 is not exactly 3 inches/11% bigger than a 26.
I have thought that since the 27.5ers are a plus tire, it would probably measure 29"-30"?
Brakes: easy to learn and even when you don’t strictly need them, they can make all your decelerating on your rides just more comfortable - when you go downhill, when you go fast or when using shorter cranks.
Multi-hole cranks: no issues, they’re just great.
Wheel size: yeah, 27.5 inch or 29 inch.
Crank length: Unless you feel particularly unathletic, I wouldn’t recommend you to go longer than 137mm. If you feel rather dexterous, you can choose 125mm.
One day you might get to appreciate the fast and smooth rides that 117mm or 114mm can provide, but don’t start with that length.
Nimbus 27.5" Green Monster: good choice. You can ask your dealer to deliver it with a different pair of cranks. Mind that its hub doesn’t allow you to add a disc brake rotor later.
I own the following unicycles:
Equinox 19" Trials
24" muni with Impact frame (32mm bearings)
26" Oracle
26" Schlumpf Guni
29" Drak frame converted to Muni
Of those sizes, the 29" is my least favorite, and I shipped it to the Midwest where we vacation. I have put the most miles and replaced the most broken parts on the 26" Oracle. If I could only have had one unicycle, I suppose the 19" trials would have to be it, because without it I wouldn’t have learned most of my skills. Of all my unis, however, the one that fits me the best and feels completely “dialed in” is my 24". That’s partly because it’s assembled from a bunch of good parts, is the most lightweight of all my unicycles and because there are a bunch of crazy steep hills in my neighborhood that I can just barely ride on it.
You might think: A 24" is only 20% faster than a 20". True. If you want to ride only a few miles, how fast do you need to ride? You’re probably a pretty healthy 60 year old, but falling off a bigger wheel means falling farther down and falling faster. I took a long ride on my 26" geared uni yesterday. Sometimes, when I was in high gear, I knew I wouldn’t be running out a UPD. Luckily, that didn’t happen.
Mounting a 24" is easier. A true static mount, the way I think about it, has no forward momentum of the wheel, no roll-back, no jump, can be performed slowly and into a momentary still-stand. The smaller the wheel, the easier it is for my to perform a static mount. A lot of riders struggle with mounting on larger wheels, and that may result in riding styles where dismounts are avoided. I think riding is more fun, however, when we can UPD without too much fear and re-mount without too much effort/frustration.
Those are just some reasons to consider a 24" as your next unicycle. It’s easier, IMO, to build skills on smaller wheels, then transfer those skills to larger wheels.
Size does matter a lot, even if it’s “only” 10%. I ended up with one or two of each of the sizes from 19" to 29", and they all have a different feel to them.
Big wheels have a lot more inertia, so they roll smoother, but are a lot harder to manipulate if you want to do anything but roll along smoothly. Inertia is basically proportional to size cubed (*), so it increases faster than you would expect.
Anyway anything from 26" to 29" is probably fine. We’re adaptable creatures and learn to love what we ride. ISIS is better, and I would get a brake.
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(*) inertia of a given mass is proportional to the wheel size squared, but mass also increases with wheel size, so it ends up being size cubed.
That is why I never bought a 36er. Rolling along smoothly is not my idea of a fun time. And my neighborhood is too hilly. Even for my less-than-36" unicycles, rotating mass is something I can’t stand. I transitioned to a lighter tire running at higher pressure on my 24" and 26" muni (Schwalbe Smart Sam 2.1"). My 29" started out as a Nimbus “Road” unicycle. It has a heavier wheel set, which makes it feel sluggish due to the combination of rotating mass and longer travel. To the OP, I suggest, if you’re getting a 29er, spend more and get a lighter-weight setup.
As a beginner, it took me 6 weeks to ride 1/4 mile without dismount. I was obsessed with the idea of riding longer distances. So I got a 29". But I ended up becoming less interested in distance for distance sake and more interested in skills, hill-climbing, riding off-the-beaten-path, choosing my lines, etc.
29" has been described as the best of both worlds between cruising and muni. I think of it as the worst of both worlds.
I love the brake on my 26". My 24" has no brake, but riding down hills on the smaller size bothers me less. Brakes are awesome, but they are also another skill that needs to be learned. Don’t expect to like it at the beginning. In order to use the brake correctly, you’ll have to learn other compensatory skills to keep you from flying off the front every time you touch the brake lever. But that’s okay, because you didn’t choose unicycle because it is easy!
Good luck!
Thanks guys!!! Glad, and surprised, to see so many close to my age on the road.
Being a retired engineer, ex-bicycle road racer and mechanic (when young, many decades ago), I understand all mechanics/physics you all bought up. Just did not know how they actually feel in the seat.
I can see a lot is individual preference. But one thing all had in common is, I will be needing more than one more uni (besides my 20" to work on skills mostly) to do it right. So with that, I am throwing my $400 budget out the window.
One reason I thought of going back to a Uni was for my dog (she does almost everything with me). She can not keep up with the bike (and I hate riding slow) and I hate running (unless there is a soccer ball in front of me). So we went for a 2 mile ride on the 20 at pace and she sure could have gone a fair amount faster. I think I was more tired than her. And no steep road hills nearby, so maybe a 29" would be they way to go there for my next purchase. Then as my skills improve, go for a Muni with a brake. But will see what size after I get the larger uni and how it feels.
Got paved roads out my front door and trails out my back door…2 doors=2 more uni’s, I guess.
Again, thanks. All your input was helpful…just costly$$ 
Happy riding!!!
The brake is also known as the eject lever. 
It takes quite a bit of skill to use a brake well. You need to lean the uni back and use your weight to counter the reaction. Start by gently applying at the top of a small hill after going into to retarding pedalling.
Letting it off can be just as disruptive as applying it. The first time I used a brake I convinced myself it wasn’t doing anything until the uni flew out from under me when I let it off.
I know a lot of unicyclists that are perfectly happy with just one unicycle. And they are both happy, and better at unicycling than 95% of this forum. I’m not sure what: “doing it right” is in your mind, but I’d say they are “doing it right”. Nothing wrong with having multiple unicycles either, but I recommend adding them slowly, and when you are sure you need them.
I’ll throw this out as a budget-friendly option: The unicycle I’ve ridden the most is very close to the UDC Trainer 29", shorter cranks being the main difference. Square-taper cranks and stamped bearing housings haven’t been a problem in five years of steady use and you’ll never run out of tires to try on a normal width 700c rim.
I’ve also got a 36" which is its own thing but the 29" is more nimble for navigating on and off sidewalks, around pedestrians, etc. Dismounts/remounts are also less fatiguing and anxiety producing. 8-10 mph on pavement is a breeze and unpaved trails are more fun than I expected, more of a challenge than they would be with a muni but the challenge is really what it’s about.
And yeah, you’ll need at least one more. You’ll always need at least one more. 
When I browse the municycle.com website and I see a cool unicycle, it starts itching and like a child I can’t wait to have it in my collection.
But now after 4 years of unicycling and 10 uni’s ahead, I found the the 29" inch Nimbus is my most favourite and I will ride it nearly every week. The ultimate wheel, 20" freestyle and 20" freewheel uni’s are just gathering dust. The seat on the hatchet is very very uncomfortable and I find it heavy to ride, so I only try it out every so many months, because it just looks wicked. Based on this I decided not to buy a 24", which I would only buy for competitions. Soon there will be the Dutch Uni Championship and I’ve decided to only do the 10km race for which I can use the a uni I already have. I have no goal to win any competition and ride only for fun.
Nevertheless to find out which wheel size fits you best, you do need to try most of them and spend a lot of money
The formula for the perfect number of unicycles is n + 1 where n is the number of unicycles you have.
Best not rush and keep an eye out for second hand deals. Unicycles is a buyer’s market and really special ones do come up occasionally, like my Triton. I only bought one new, the eSport.
Sorry but this made me smile 
misquoting at it’s finest… 
But still kinda funny. (In case anyone wonders, both was meant to be referring to beeing happy and beeing better at riding)
I’ll argue against that. You can be happy with what you have, without wanting to try anything else. A lot of Trials/street/flat/freestyle riders only have one “real” uni. (I wouldn’t count the beginner uni almost every unicyclist owns.) Because they know what they want to do, and just do that. And no, they probably don’t feel like they are missing out on anything.
Don’t overcomplicate things.
Once you get a few unis it becomes tempting to customise them.
One of my favourites is my 26 because I built it as a lightweight roadster. No brakes. Looks mean and simple. Only weighs 5 kg. Rides like a small uni but much faster.
KH frame, Nimbus Dominator2 wheel and an ultra lightweight folding bead Maxxis DTH tyre. I used the Dominator wheel despite it being marginally heavier than the KH rim because I like its all black look, with no rim cutouts and no machined brake surface plus being narrower it made for a slightly larger rolling diameter. 114 Venture cranks. The original KH wheel has an off-road tyre and Moment 125/150 cranks. I can swap the wheels in a couple of minutes.
My 29 has a Dominator wheel in a KH frame. Once again, narrower rim and no cutouts. Maxxis Torch tyre. Venture 125s. Magura brakes. I also have another 29 wheel with the wider KH rim with an off road tyre and 150 Moments.
The 36 is a glorious sight with a Titanium frame, all black Dominator2 wheel, Spirit cranks, disc brake, flat carbon fibre saddle and short KH bars. One day the original wheel will be fitted with an off road tyre I have in my collection.
My road 20 is QuAx Profi wheel with a Hookworm tyre, black double wall rim, 48 black spokes and a red ISIS hub and 100 mm cranks. Indestructible. Red saddle clamp to match. I only paid $50 for the uni. I ride it as fast as I can down moderate slopes to build up my cadence. I put the wheel in the Quax Luxus frame.
My indoor 20 is the QuAx Luxus wheel in the square shouldered Profi frame. I rebuilt the wheel with stainless spokes. All polished chrome and aluminium with a white tyre, a gold saddle clamp and matching valve cap. It originally cost $60 and was only $24 for the new spokes.
My trials is an old KH frame with a surprisingly attractive distressed red paint job it came with when I bought it. I fitted it with a gorgeous Impact Athmos wheel (white rim without cutouts). OBR Gekok tyre. Only paid $75 for the Athmos. The old Onza wheel is now in the Athmos frame. It has a short seat post so I have two trials machines for teaching different sized learners.
The 27.5 is a recent model KH with Spirit hardware, Zero saddle and a disc brake.
There are more, including a Nimbus giraffe and two UWs. Still trying to work out how to tackle them. The little no-brand I learnt on, a Club in need of love that came free to a good home with the giraffe, the eSport and an LX Torker 24.
Not so many really, is it?
Matt B,
The size of uni that would work best for you really depends on how fast your dog likes to travel. Assuming a comfortable cadence of 110 RPM the uni speeds would be 20" ~ 6.5mph, 26" ~ 8.5mph, 29" ~ 9.5mph, 36" ~ 11.8mph.
I was in the same situation as you, I rode a 24" as a kid and after a 50 year break I picked up a 36’er" a little over a year ago specifically for road riding. It has worked out great and I’m glad I did not get anything smaller. For road riding and covering some distance and 36’er is hard to beat but I do not have a dog that has to keep up with me.
Jim
Sure do appreciate all the info from my original post. I understand where all you are coming from, no matter if you call it black, white or gray. I grew up on skis (both alpine and x-country). Got only 2 pairs (1 alpine and 1 for x-country). I can come down probably on a pair of wood boards better than 95% of the people on the hill as I can adapt very fast to what I have under my feet (to quote a couple posters). But unfortunately my current uni skills are no where near my skiing skills, and I know it is the rider skills that count the most.
Right now I have a 20 year old Schwinn 20" that I got off Craigslist for $15 (Seller said $30 or $15 if you can ride it). It was never ridden (like new) and he gave me 3 tries (since it had been almost 50 years since I had been on one). The second try I was ridding (with the seat 6" too low), so $15. It has no grab handle on the seat, steel rim, 1.75 tire, steel cotterless crank, etc. I just bought it to see if I still enjoyed ridding as I did 50 years ago before spending real $$$ for one.
Yesterday, on a trail, one of the larger tree roots bit me (pedals at 6 and 12), boy did I go over the top fast (not a UPD, so I DO need to buy some safety gear:)) and on softer ground, I go in deep (not 60lbs, like when i was 9 years old). So I am sure anything I get will be an improvement off road from what I have now.
I was shocked on what a workout I got on EASY trails. Being a beginner, I am sure I was making it much harder than need be. But it sure was a challenge, intense concentration, and FUN!!
The typical beginners 20 and 24 uni’s seem easy to find, but the more serious larger ones, much harder. You guys did get me thinking about 1 uni with 2 sets of wheels.
BTW- I went back over that same trail (and that bigger tree root) later that day, and with success … another small victory, but a victory!!! Wish there were other riders here I could learn from, I could use it.
Going to go for a 26" that can accommodate 2 sets of wheels (if I decide later to add a 2nd set).
Again, thanks to all. It was helpful!!!
Thanks Jim. I learned on a 24" too. Was way too big for me at the time, but what I had.
I was wondering what a typical uni cadence was. I did the same calcs using a 90RPM cadence. And converted it to “x” minutes/mile for the dog for each size wheel. The 36" was out of her comfort range for a longer ride/run.
She is well trained so will go whatever slower speed i go, but seems to like the trails in the woods behind us best. She knows she can do what she wants there (until I call her) and I go slow enough she gets “squirrel chasing”, “a fast swim” in the creek or ponds, etc in too.
Jim,
Just looked at your age and pic…very inspiring to us over 60 beginner (again) guys!!!