Due to this post by @pierrox I got curious and ordered a pair of Prowheel 127mm cranks.
It seems Amazon have 127mm/140mm/152mm cranks available both in the EU and the US.
Here is a quick photo comparison with some KH Spirit 117/137mm cranks.
For a second you had me excited thinking there was a new triple hole option on the market 
It will be very interesting to see how you like them. They are very affordable.
I wonder if the the Prowheel cranks are strong enough for a uni. The Prowheel cranks are made of “aluminum”. The Spirit cranks are made of aluminum 7050 alloy. 7050 aluminum is a heat-treatable alloy which is known as a commercial aerospace alloy. The alloy offers a combination of high strength, high fatigue strength and high resistance to stress corrosion cracking.
Pure aluminum has a lower yield strength, around 30 MPa (4,000 psi), while high-strength alloys can reach 476 MPa (69,000 psi.
According to the listing, the Prowheel cranks are made with 6061, compared with the KH’s 7050. What that means for crank strength… I will leave for somebody else to explain since I am not too familiar with different grades of metal 
That is Yield Strength:
6061-T6 (Heat-treated and artificially aged) Around 40,000 psi (276 MPa). 6061 is less then 60% as strong as 7050.
I’d guess the electric bike cranks don’t have to be as strong as uni cranks.
Nice!
My guess is they’ll be fine for uni, but muni is another question.
After all, the Quax are made of a butter-aluminium alloy and they’re fine with road riding:
https://www.unicycle.co.uk/product/qu-ax-lightweight-isis-cranks/
Agree. Mad4one also makes their cheaper cranks (unicycle stuff and blueline) in 6061-T6 so they are likely fine for general use.
would you say that MaxQ is better or worse for muni? By having it wider you create more of a platform and balancing should be easier, but possibly for maneuverability narrower would be better. As I tend to ride with 150mm cranks, I possibly should look into a 150mm Q-factor as well. A bit like that other pic I showed with the tractor wheel 
Last tech spec (for 127mm pair): 391g
They are beefier than the butter Qu-ax ones and definitely heavier.
Nice Q and affordable. I am very confident they will do fine for road and even on fire roads they will hold their own better than the Sinz ISIS used back in the days 
You’re asking if the Q factor is good for muni? While I think Q factor is mostly personal preference, I think more Q is more of a disadvantage when you need to spin really fast like for road or track riding. So for muni usually less of a disadvantage. For slow-speed muni uphill like the half-rev–pause–half-rev, the higher Q can also add to your power.
I would also add that a bigger Q-factor may induce a better stability. That’s at least what I seem to have experienced.
Nice find, always good to have options
What is Q-factor? 
Fair question. Easier to show a picture than try to explain.
Source: What is Q-factor and does it matter to you? | Cyclingnews
Obviously a unicycle is a bit different than a regular bike as larger q-factor does not introduce more wobble on a regular bike - however I personally also believe that it’s mostly a matter of finding a setup for your body that works well to avoid injuries. I haven’t been able to recognize any difference when riding cranks with different q-factor myself yet.
Agree. I‘m not really comfortable with the large Q factor that is a result of the 125mm hub of my 36er Oracle - my heels regularly touch the cranks. But I‘m fine with the same 125mm hub (except it is steel vs. alu) on my Nimbus Oregon muni.
It is strange, but I realised that I don’t have problems touching the cranks with any of my shoes on the road (as long as I don’t try to shift gears obviously). So I switched back to 0 Q many years ago. Even though my Schlumpf is somewhere in between 100mm and 125mm wide. Also no problem with 0 Q on the 19" trial btw.
I would argue that less Q factor should help not touching the cranks. The further out you bring the pedals, the more likely it is that your feet would naturally want to sit closer together and rub on the crank.
I see how high Q-factor cranks will help by placing a “barrier” to help against accidental shifting for some Schlumpf users though.
I can’t really make sense why a wider stance should help balance. Doesn’t matter how far you put the pedals apart, you are still standing on only the small contact patch of the tire on the ground. Whenever I’ve played around on one of these:
Riding trials with a lot of seat out a wider stance helps “lean” the unicycle with your feet with the added leverage. Same on a MTB where you ride fully standing up and the bike actually has a decent amount of room to move. On a Muni where the seat is caught between your legs, I don’t see much ability to use any extra leverage. (At least not for me).
Long story short, I tend to agree with @MUCFreerider mostly personal preference (likely whatever suits your body) with the main noticeable difference that narrower is a bit easier to pedal smoothly.
With some luck, maybe they use the same forging for all sizes and someone could drill out some extra hole(s) in the the 152 mm cranks. 127mm/140mm/152mm is not adviseable though, since the threads would overlap…
At first glance I could agree with you, but now that I think of it more, having shorter cranks, it makes it harder to balance for me, like I have need to be more in the middle of the uni than with 150mm cranks. To me it feels like with shorter cranks you have a smaller platform to balance with, so possibly when having my feet further apart, makes it easier for my body to balance. It doesn’t matter so much that the area that actually touches the ground is only 1 square cm small.
Also in that way, handle bars make that area of balance bigger. Then again when there are oncoming cyclists I tend to sit upright and not touch the handle bars, coz I feel more in control that way. Prolly depends on what you’re used to as well.
I have like 7 holes in my UW. 3 is like nothing compared to that. Now that I’ve seen the Korean guy moon ride his big UW, I might also play around with placing the pedals closer together.
