One length to rule them all

Back problems have made me give up on rough muni and real trials, so I swapped the trials uni 140mm cranks for 125mm to make it more general purpose. And since I was doing more XC style riding, rolling over everything instead of starting and stopping and hopping, I went for more speed, and moved the pedals on my 26" and 27.5" muni rides from 150mm/145mm to the 125mm holes.

Meanwhile my experiments with 100mm/110mm cranks on my 29" and 36" road wheels made me decide that:

  • I prefer the extra control of longer cranks vs. a little speed that I don’t care that much about
  • Atlanta is hilly enough that short cranks make things a real struggle
  • and biomechanically, my legs prefer longer cranks anyway. On short cranks, the “power stroke” part of the pedal circle is too small relative to the “power stroke” part of my leg extension.
    So I’m using 125mm on those wheels too.

End result, the fleet looks like:
19" trials - 125mm
26" muni- 125mm
27.5" muni - 125mm
29" road - 125mm
36" road - 125mm

I guess one size fits all!

(there is also a 24" wheel that has 140mm cranks; I mostly use it for walking the dog or crowded street events where speed is irrelevant, and the leverage to haul on the leash when the crazy foster dog takes off after something is handy. Also I don’t have any more 125mm cranks…)

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Nice… !!!

Please be warned, if you come out to Seattle, most locals consider the STP (Seattle to Portland) a flat ride.

My physical therapist would agree that one size, if possible, will be best!



If you’re looking at selling some of those old crank I have a 26 nimbus MUni with 165 cranks and interested in shorter or mult-hole cranks. Looking for 150ish. If you have any extra from your recent modifications, I would love to buy them.

Agreed that 125mm is the most versatile crank length, and if I could only have one size that would be it. I do run different lengths for different unis to keep me on my toes though.

2 out of 3 of my unicycles are on 125mm currently, the 26" Muni and the 19" Street/Flat. Completely different use cases and reasons for choosing them, the lower moment of inertia (flips faster) being the main reason on the 19", and the ability to pedal fast with relatively high amounts of control being the deciding factor on the 26". Only the freestyle has 100mm cranks (which is still pretty long)

But I agree with you, to me it also seems like it’s a good size biomechanically. I feel like 125mm-140mm all work pretty well for me on a unicycle. Over 140mm I feel like there is diminishing returns when it comes to control. 140mm and 150mm feel almost the same control wise, but 150mmm feels a lot slower to me. Below 125mm the decrease of control feels drastic to me (but at least I still get noticably faster). Probably something to do with how much of the pedaling you can do through the ankle vs. hips and knees.

Anybody ride a “Three for one” Crank?
My VCX “plus” crank has 3x holes 150/125/100 mm’s.
I mostly ride with 150mm, because I like to ride offroad and do flat land tricks.
Longer crank=more climbing power and allow for slower/more accurate control for stunts like stalls/idles/backwards/going over obstacles.

I have experimented with 125mm sometimes, but the shorter leg pump=increased instability and wobble.
However, my biggest concern is the “extra length sticking out” when I use the shorter crank length options.

I’m curious if there are any unicycle riders with “multi-hole” cranks that have had UPD’s or injuries from the “extra length stub” when installing pedals on shorter holes?
I appreciate any feedback and stay safe ride away from public.

I agree with your thinking. However, I have not quite gone for 1 size fits all.

I prefer 150s for all round riding on the 36. I ride on and off road without a brake and prefer the easy mounting, and control of the 150s to the 125s.

I prefer 150s for off road on the 29, and 125s for general riding.

I have settled on 150s on the 24 Muni.

I have 114s on my lightweight 28.

I have used shorter cranks (down to about 75 mm on the 28 (and 20 when I had it)) and longer (170s on the 24 (and 26 when I had it)) but have concluded that "mid range (125 to 150) is best for everything. I’d rather lose 1 mph peak speed for the extra control. You can learn to spin long cranks a bit faster, but there is a limit to how much torque you can apply to short cranks.

Chacun à son goût. There is no right answer, only personal preference.

Eat more Christmas pudding :wink:

I tend to like something shorter on smaller unis but probably because I do a lot of road riding. That said I have been running 125mm on nearby trails of late, with my 24". Mainly because the route I have been riding is so steep that I don’t think I could manage anything less and still get up the hills. Also this experience has taught me that 125mm isn’t as bad for all-round road riding as I thought. It is certainly doable and makes hills easier.

I was until recently using 125mm on my 36" but after lending it to a new friend (who I thought might be better served by longer cranks) I switched it to 150mm and never got around to switching back. These also worked out better than I recall and were much easier on hills and mounting, which has made me re-think things here as well. I suspect in the long run I will run this with 140mm.

What I take from all of this is that 125mm is a good compromise, all round size but personally I still appreciate other sizes more. If we could only have one, then sure 125mm seems reasonable.

Yes but I run them at 100mm 90%+ of the time.

Not once that I recall have I had a UDP because of this.

slamdance, I did have one instance where my instep strap on my gaiters was too loose and caught the extra length on the crank.
Luckily I was climbing and was able to get my other leg down just in time.

150 for Muni. 24, 26, 26 fat, 27.5
138 for 36, 29 Guni
125 for 29 road


Not for me, but with qualifications. I have 127/150s on my G36 and my 26" Muni. Mostly they both get ridden in the 150 holes, but I haven’t ever had my foot get lifted off by the end of the crank, nor have I noticed it at all while riding in the 127 holes. Note that I use grippy pedals with 5.10 shoes, so my feet don’t move around unless I want them to. :slight_smile:

That said, one size does not fit all. It may for some of us, but in general, it’s like saying one wheel size to rule them all. That’s a NOPE for me. It really depends on the type of riding you want to do with each wheel. For me, Muni in the 125 holes is great, unless it gets steep or technical. Part of this is because I’m used to the 150s (previously 145s on my old Wilder), but part of it is also me wanting to be kind to my knees. Also my formative years of Muni riding were on a 24" wheel with 140s. This was a 24 x 1.75" wheel, mind you, at 60 psi to keep the rim off the ground. That’s a different kind of Muni, but really all that was available at the time.

For Road riding, the crank size you need depends also on the terrain. On level ground you can get away with 102s and have a great time, though none of the places I like to ride are that flat, so I used to go between 114 and 110s before I got my Schlumpf. The Schlumpf has had me at 150 since day 1, and that size seems to be appropriate for the mix of riding I do.

For Freestyle, or most types of riding on a 20" wheel outside of extreme tricks/jumps/drops, 125 is pretty darn long, hitting the ground as you make turns. I currently have 114s on my Freestyle uni, but that’s because I learned with 125s. I really need to work my way down to 102 or 89.

125mm is too short for me. I like the 150mm on my 26" and up very much. No probs with mounting or riding uphill. Sure it isn’t superfast, but that is less important to me.

I have the same VCX 100/125/150 on my 36 and have never had any problems or any worry about the crank sticking out (same goes for my Spirit 127/150 where I have done lots of time off-road in 127s without problem/concern).

On the 36 I really like the triple crank: 100s for fast road (but I can switch to 125s if I get tired or have more climbing), and 125s for XC and 150s for anything more technical where I need more control.

Interesting info here… I’ve been experimenting with crank length a lot in the last year or so, especially with shorter cranks for DH and XC. On the one hand I am really happy with the shorter cranks, and I think practicing has improved my overall riding (but you have to first improve your skill a lot and fitness before you can try shorter cranks!).

I have been riding 125s on my 36 for XC and now feel very comfortable (at first the lack of control was scary and it totally exhausted me physically). I have also successfully tried XC with 100s on the 36, and while possible, it’s just too short for most XC (#1 exhausting! but also climbing ability is reduced to momentum only).

However, recently I’ve been having a little pain/discomfort in my previoulsy injured right knee (ACL reconstruction and miniscus damage) and unfortunately I think the short cranks are part of the problem… About a month ago I did a big muni tour that I have in the past done with 150/127 cranks where I did >600m climbing on 137mm cranks on my 29+ and afterwards I really felt it in the joint :frowning: Then last week I did a big muni tour with >1200m vertical (didn’t ride all the uphill) with 137mm cranks on my 29+ where I rode probably close to 700m vertical uphill and afterwards my previously injured knee again felt overworked and weak for 2-3 days (I did an XC ride 2 days later on the 36 with 125s and could still feel the weakness).

After riding primarily 125mm on the 36 and 127mm on the 29 for XC for most of the winter, the last 2 weeks I rode the 36 XC with 150s, the 29+ XC with 137s and enjoyed the longer cranks. This week I did 2 big muni tours with 137mm cranks on the 29+ and intentionally walked more uphil than I usually would: 3 days ago I did 1800m vertical with a lot of walking and around 400m uphill riding and today I did another big muni tour (1030m vertical) where I walked a lot and rode about 300m uphill. While my muscles seem able to push the 137mm cranks pretty well even on steep uphills, the 150mm I used the last years seem to be nicer to my knees. If I really push with the 137s I seem to overtax the knee.

To summarize (what’s used to mostly be in my signature but that seems to be gone in the new forum update):
freestyle 20" 89mm (although I would like to try 100s some time)
trials 19" 140mm
26" muni 117/137
29"+ muni 117/137 or 127/150 — ideally 120-130 for XC, 120-137 for DH only and 137-150 for muni tours with lots of climbing.

As for technical downhill (no major uphill): On my ride today I rode a DH trail with 350m vertical drop for the first time but rode it twice, back to back. The first time I rode with 137s and the second time with 127s. The trail was not extremely steep but very narrow and pretty rocky but without any big drops. The upper part of the trail was difficult while the lower part was less technical (so faster). On my first run with the 137s I had no major UPDs (although a number of controlled dismounts) while I had 2 major crashes with the 117s – bruised my knee a little :frowning: – and successfully rode 3-4 key passages with 137s that I had to dismount on the 117s. However, some of the downhill sections felt easier and more flow with the 117s. I guess my feeling was this: as I was riding with the 117s, even in pretty technical rocky/rooty downhill sections, I felt better with the 117s up until I lost control and then it was much harder to gracefully recover on the 117s as compared to the 137s… of course, I’m not used to riding DH with 117s so that might improve with practice… I was wanting to compare my speed from analyzing and comparing the two tracks but haven’t done that yet.
So I may switch back to the 127/150mm cranks on the 29+, as I feel more comfortable with 127s on downhill and XC, and the 150mm seems to be better for long uphills, although I think I would ideally like 125/145 but the KH spirits don’t come in 125. (a triple crank 125/135/145 or 120/130/145 would be awesome but the spacing is too close).

Uh, sorry for the near stream-of-consciousness disorganized rambling… but kind of my thoughts and been riding alone all the time (I guess most others are too now, and I should be thankful I can even ride in these strange times).

except for the 20" and 19" (on 125) all cranks are now on 140mm (really my prefered size)…

These days I ride the 36" 99.9% of the time…and I use 114mm. I tried 100mm last year and it was horrible. I thought I’d be able to spin faster but it just seemed like too little leverage, and oddly enough it greatly increased my saddle soreness somehow. 125mm was my favorite but the 114s seem perfect, and I will go no shorter. I can still even handle a moderately bumpy trail and drop off many curbs with speed with the 114s too whereas with the 100s that would seem impossible.

137s for the 20" hands down. I don’t ride the 24/26/29 anymore but I’d probably use 114-137mm for those.

@DSchmitt, what’s the rest of your 36er setup?

I, like you ride my 36" almost all of the time now and I’m running 110s there. I’ve been running 110s for years now though and since moving to the Nightrider Lite I’ve considered going a little shorter.
If I end up getting myself a carbon rim at some point then I feel like that might push me into the 90-100mm region.

I’m looking for a set of ISIS 150 cranks.

Not intentionally but all my unis have 138s I find them to be very versatile