I am a newbie muni rider and wanted take advantage of the collective wisdom on this forum! It seems that the size for a 24" muni cranks range from about 150 to 175mm. I realize the shorter cranks will give you more speed, while longer one give you more climbing ability/power, right? I am currently riding on a local bike trail which is fairly hiily/bumpy in some areas, but overall it is not too severe. For a newbie like me, wanting to build leg strength and lung power, what would you all suggest as far as crank length? I am prepared for those who might tear me a new one for asking such stupid questions 
(But I really appreciate the help!)
Btw, I searched the FAQ section first, but nothing came up for “muni crank length” or other similar phrases. Thank you all! I am gearing up for Moab!
the logical answer would be 162.5mm cranks… but that aint possible!
If you’re getting ready for Moab, you want long cranks, probably 170mm. The Slickrock Trail is all very steep up and down, and you’ll need all the leverage you can get. Shorter cranks can be more fun on less steep or less technical terrain, because you can ride more smoothly and get places faster.
I use 170mm Cranks on my 24" Muni. I often think about changing it to 150 and I still keep a set of 150 in my house but at least I prefer more Controll and this you got with 170 Cranks.
My biggest Problem is always to change the Uni after some weeks on the 24" with 170 to my 20" with 114 Cranks 
It needs some minutes to got control.
I rode 170’s on my 24x3 Muni when I first started, but switched to 150’s. My inseam is only 30" and the 150’s seem to work better for me (less wobble)
Go with 170’s, at least to get started. Later on you can experiment with shorter stuff if you like. Ive been using 170’s 3+ years and they are perfect for the type of muni i do. Also, 170’s are the most common crank length for 24x3 munis.
165 or 170, the top brands currently all (i think) use 165 but my old KHs are 170s. I started on 152s and 170s are deff more powerful, although they are more likely to bend or break either themselves or the hub (larger moment). I also occassionally use 140s on my 24", they’re good for things like BMX tracks where there are no very steep up or downhills, but where speed is important. Hell I even used to do trials on them because I couldn’t be bothered to change them, but basically 165 or 170 will see you right for Moab.
It really does depend on your riding style and where you ride. I ride 150mm and can pretty well ride what I like with them.
Roger
I like my 165s. If anything I’d go shorter, though. i tried 150s and they were really nice and fast. not so good on slickrock, though. (this was at moab last year.)
The more experience and fittness you have, the shorter cranks you can use. I just switched to 150s (from 165s). Steep uphills are doable, and with time you can roll out steep drops easier, and descend steeper rock, since your legs aren’t moving so wildly. It takes some time to get used to the reduced torque, and you have to use a brake on the turbo-steep stuff (I never used a brake with the 165s), but over time I think I’ll start doing stuff I couldn’t do before.
I got the idea from riding with Kris H., who also recently converted to 150s. I’m not quite where I was with the 165s, but am getting there. . . One thing is for sure–the speed increase is pretty remarkable.
That much said, I started with 170s, and figure that’s pretty much where everyone should start unless you’re Muniing on low tech flat stuff.
JL
I’ll vote for the 150s also.
Things to note:
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When you say 24", it could mean a “regular” 24" tire, which is about 24" diameter. Or it could be one of those really fat MUni tires, like a 24x3, which is more like 26" diameter. When I used to ride a 24" uni on trails, I used 140mm cranks.
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The best crank length for you depends mostly on your personal taste, and the steepness of your terrain. Sounds like your terrain isn’t real steep, so 150 should be a good place to start. Yes, if you go to Moab get some longer ones though!
Meanwhile, I have the 170s that came with my Wilder, but most of the time they seem long for me. I’d like a pair of maybe 160s… yes, even for Moab!
i’ve ridden 150s 170s and currently 160s, on 24x3 munis. i prefer the 160s as the best all around. Around thanksgiving i rode almost everything at moab on 160s. i think 170s (in general) are too slow and after a while they start to hurt my knees. 150s are great for flatter, longer courses, but lack serious leverage when climbing. i think 160s are the best all around crank length for muni.
I rode 24"x150’mm cranks at Moab last year, and on the whole slickrock trail was able to ride up every uphill I came too.
Towards the end, I realized why the majority of people were walking up those steep hills… I was pooped!
I’ll still have 150’s at Moab this year, but I think I would like best 160’s or 165’s. I’ve briefly ridden 175’s, and I think they’re only suitable for very technical riding, if not all out trials.
I found these 165mm cranks at bikeparts.com. Does anybody know if these will fit the torker dx 24"? It is 10 splined just like the torker. Go here to read specs.
http://www.bikeparts.com/search_results.asp?ID=BPC102116 
