Get dual hole. You may outgrow the 150s pretty quickly. I ride my 29 muni on 125s on the road.
Get spirits, 127/150, or if you want to save money try to find dual hole moments on the trading post or around the Internet.
150s on a 29 will get old once your skill increases.
I as well would suggest duals 127/150.
The shorter the crank the less control you will have. but once you get used to your new 29er with 150’s you just might want to try out the 127’s.
What about getting the 138mm since that’ll be between the 127s and 150s?
Would the 138 (in the drop down tab upgrades) be the best since it’s more speed than the 150s but more control then the 127s? Wondering myself.
It’s really personal preference and riding skill/technique. You probably won’t want shorter than 125 even for road, and you wouldn’t want much longer than 150 or 160 for muni. That’s why everyone keeps suggesting dual hole 125/150
5.5"/137/138/140/whatever seemed pretty much ideal when I started riding my 28" road uni with just a couple months’ unicycling experience. That’s on the limit of what I could handle going down hills in my neighborhood without having learned to use a brake. Going up hills was never a problem.
110/137 seems like it might be a better dual-hole solution if udc can be talked into an upgrade not listed in the drop-down. Lots of folks ride on the road with cranks as short as or shorter than 110. With it not being a mountain unicycle, I don’t see the usefulness of a 150 mm option.
As Dane mentioned it’s somewhat related to preference & riding skill. I very seldom use my 150 crank option on either my 29 or 36 but if I’m having a bad control day then I switch to the 150’s and things just seem to feel better.
At least with dual hole units (regardless of what combination you chose) you get some variety without having to pull the crank arms off.
Duel it is… Thanx
Hi all … Appreciate the guidance and for taking time to provide… Looks like Duel it is then… Jimmy
Yeah this is exactly what I’ve been pondering for awhile. After getting the 127/150, I sorta like the 127s for the speed and smoother pedaling and 150 for the better control and easier stops and then I’m wondering why not have a bit of both and get 137.
I also would think that the 110/137 would be the most ideal combination if UDC lets you choose. The 110 would be fantastic for speed on the road and the 137 would satisfy those that want the inbetween of the 127/150 spirits.
But the dual hole suggestion in general is a sound idea even though that’s a $95 upgrade 
Because it doesn’t work that way. You don’t get the benefit of both. It’s not like you gain control AND speed. You lose from both sides.
But without trying them you will never know what YOU prefer. People can tell you all day here what they like, but in the end, it’s what feels right when riding yourself. You can always get 127/150, and if you find you want the shorter variant of dual, sell them here. They will sell quick and pretty close to full price if not damaged. Then you just buy the pair you prefer from udc with the free shipping code going on right now.
From my point of view, with just a bit more experience than the OP and doing similar riding, 137s give the benefit of “just right” without the disadvantages of “too long” or “too short.” 
Down the road with more experience and braking skill, 110s would be excellent for long rides, with 137s as a fall-back for big hills or more control on bad days.
I’ve got 150s on two unicycles and they’re fine on trails but I hate them both on the road. Too much monkey motion, and I’ve got fairly long legs. More wobble, less control…
But looking through old topics at rider preferences for 36ers (easier to find, more discussions about) you’ll find an advocate for every length from 100 mm to 165 mm. So yeah, personal preferences…
Very good point. Good ISIS cranks always seem to move pretty quickly so it’s not quite an irreversible commitment.
150 seem painfully long on a 29er for me. Even when I was very new to riding I quickly moved to 125’s for road. Some of the hills around here are pretty steep, and I don’t think I could have controlled my uni with those cranks without a brake. So, if you are going to have a brake shorter cranks can be an option. I found that for regular all around riding, or XC MUni 140’s were the most comfortable.
I guess I’m the odd man out on this one, but I do think the 140’s offer better spinning, with very little loss of torque for climbing. For me they ended up being the perfect length on 36, and the perfect longer crank on 29. That said I have dual hole 120/140s that are just about perfect for everything.
So, I guess another vote for dual holes.
Unnecessarily dogmatic - several people have already posted that they prefer 150’s on their 29-ers. I’ve been riding close to 20 years and still prefer 150’s.
Not saying that some don’t favour 125’s or even shorter, but, to tell a beginner that they will dump 150’s when their skill improves, is just not true- they may, they may not.
As many others have already said, dual hole 150/125s are a good way of deciding which length is suitable- I had some and enjoyed the ability to dismount and easily switch lengths, they helped me conclude that, for me and the terrain I ride, the 150 setting was best (though I currently use quax cranks, which are either 145 or 140mm?)
No, I’m with you. I think of the default 125 mm cranks as being the compromise, in between 137/140 for hills or better control and something shorter for serious spinning on fairly flat routes. Still being a pretty new rider and with nowhere to get in any hurry, I’ve been sticking with the longer of those lengths.
Who makes those? I don’t remember seeing them and can’t find such on the UDC or UDC/UK sites.
They are square taper Trek “Dialed” cranks with the chainwheel removed. You won’t find them on any Uni site.
They also have 127/152 Dialed cranks.
Cute. I particularly like how the holes are labeled “7 & under” and “8 & over” on the longer ones.
I just have a bag full of steel United cranks in various lengths to try out on mine, as well as on my Avenir.
For me, a 29" for flat road riding would have 102mm or shorter. But you are not me. If the two hubs are of the same type, I recommend starting off by going the cheap route. Take the 125s off the 29" (but give them a try first) and swap them with the 150s on your other uni. Both will be great. You might need to get crank puller too, and learn how to use it, which is worth doing.
To add another riders point of view…
I’ve been pretty much only riding 29 for a year now. Have done most of my riding on 125’s and 110’s, with some riding on 150’s and some on 137’s.
Most of my riding has been road riding, I live in a fairly hilly area.
If I could only have one set of cranks it would probably be 137’s. They would be a bit long for road (but not too long, very usable). They would be on the short side for off road use, probably too short, but most of my riding is on pavement.
In the beginning I would have been all for 150’s, it took a while to get comfortable on the uni, but outgrew them after two weeks. Was very happy with the 137 and 125 for a long time. If I lived in a flatter area I probably could have settled into the 125’s for good. But then I started riding longer and wanted to see if I could go faster, went to 110’s. Pretty good for a road machine, I definitely was not as confident with them, mounting became much harder, control in dicey areas suffered as well. I wouldn’t want the 110’s if I was in high traffic areas, or where road conditions were not great.
I hope this helps. The truth is one size doesn’t cut it. 125’s would make the most sense to me in your situation, but there is going to be a longer learning curve at the start. Also every one is different, some people like to spin big, some people like to spin small. Some have good strong knees, some have bad weak knees. It’s good to have a few different sets of cranks anyway.
I’ve got a set of 150’s, 137s, and dual hole 127/110. It really lets the uni shine on almost any terrain, it actually amazes me how versatile my 29er has become.
Ordered the KH duel cranks
The Duel 125/150 KH Cranks were ordered with the New Nimbus 29"Road and am starting out with the 150s … Thanx again … Jimmy
Great choice. I think they are much cheaper when you order them with the uni.
Well its an “upgrade” price. You lose the stock cranks and upgrade to KH cranks, that’s why the cost is lower when added on.