Crank length: can’t tell the difference?

I’ve got two kinds of dual hole cranks (125/150 and 137/165), and can definitely tell the difference when I move the pedals to the other holes.

Recently I was halfway through changing out a set of cranks, and thought, why not try riding around for a few minutes with 150 on one side and 165 on the other. To my surprise I couldn’t tell the difference. Even I had to look again to see which side had the longer crank.

I wasn’t intersted in a longer experiment and am anyway not fundamentally interested in crank length. Yet sitting on the train this morning, I find my self idly wondering, how much of the different feeling of different crank lemgths is just in my head? Can we notice a 25mm difference but not a 15mm difference? Do we notice differences more in the shorter vs longer ends of the length range? Does it become apparent only with a longer ride over varied terrain? Or should I do some meditation exercises to focus my attention on the precise diameters of the circles that my lower legs are tracing out? :roll_eyes:

Had a similar thing happen to a friend, he actually did it on accident. I think it was 137mm and 145 on the other side. He didn’t notice at all, someone else borrowed his uni and thought it felt a bit weird

If we compare 85 mm to 100 mm, and 150mm to 165mm, the difference you feel is going to be much bigger on the shorter combination, despite both being 15mm. It’s all relative.

Some of it is in our heads, for sure. I once rode a borrowed 36" and thought: man, these cranks are long. Checked at the next traffic light, and it turns out they were 125mm, just like I’m used to.

I’m pretty sure I really feel 125mm vs. 140mm. 150 vs 175 I’m not sure. All relative.

I think how much you would notice it would be related to your skills

If you’re a decent rider then you’re already used to adapting within milliseconds. So right leg adjusts… then left… then right…etc…
Kind of like having bad foot placement for 1 or 2 revolutions or having a foot come off of a pedal and then recovering.
You deal with it.

Your brain does what it takes to keep you riding.
Humans adapt… unicycling humans adapt even faster.

Rookies need all the stars aligned, pedals flat, 5-10’s, special tire, and… the exact same crank lengths because everything about it is hard.

Too much emphasis (physical and mental) on the individual components is common for the rookie looking for an answer as to why this is so hard.
Better riders compensate and keep riding.


You guys are still using cranks???! You should learn to just will the unicycle to do your bidding.

Back in my hardcore Freestyle days, I think I could probably detect at least a 3mm difference between one side and the other. This is when you’re working on backward figure-8s one-footed and stuff like that, where it really matters.

But for straight-ahead riding on longer cranks? Now you make me curious to try it. I’m sure I would feel the difference, right away, but how much would it affect me? It would be more fun to try it out on the trail. I have 127/150s on my KH Muni. I wonder if I switch it on one side, then on the other, if one side will find riding the hard stuff easier than the other? How much does one’s dominant foot have to do with making it through technical sections? Interesting questions!

Interesting thread! New to unis but experienced with bicycles and so I am accustomed to thinking of crank lengths in terms of their leverage, whether longer for climbing hills or shorter for speed, etc. But I am catching on as to how crank length could affect the performance of unis, that longer cranks could be more sensitive in terms of traction and directional control, especially as bicycles rarely ever go backwards, for instance. I just now took delivery of my brand new beginners model 20" uni and crank length was part of my choice in selecting this particular one as my first uni. Of the 20" models, shorter cranks typically go on the Freestyle unis and longer cranks typically go on the Street and Trials unis, and I figure that much of my early lessons will be done at short distances, from idling to closely nearby, where pedal input sensitivity and control would be most important, similar to the Street and Trials unis. Oh, the Freestyle unis need those things, too, but their performances seem to commonly be done at slightly longer distances.

I am new to unicycles but have experience with bicycles and as a paved road riding commuter I could fairly quickly notice a difference of crank arm lengths on a bicycle but fortunately bicycle cranksets come in matched sets and so it would be unusual to have mismatched crankarm lengths on a bicycle.

I have VXC+ cranks. Today when I was switching them from 125 to 100 I remembered this thread. So in the spirit of experimentation I tried moving one first and attempting to ride. It was not half as strange as I had expected and certainly I could ride like this with no issues. On the other hand it was still a little weird and I could feel that one leg was doing bigger circles.

Of course the difference from 125 to 100 might feel greater and this was on a 26" wheel which might also effect things.

Sorry, I meant VCX+

Another curious one here! I’m going to have to try this!

I can definitely tell the difference between different matching crank lengths on my unicycles, but when you’ve been riding the same setups most days for a number of years, you get used to exactly how things are.
On other people’s unicycles, it think I could work it while riding, but the whole experience is normally so different anyway.

On a similar note, has anyone else tried offsetting a crank by just one spline on one side? Now that is weird.

LOL. Only a uni nut would think of trying that. Although I remember, as a kid working in a bike shop, accidentally installing both crank pins in the same direction, probably about the same result.

Totally doable, but definitely an odd way to ride…

Pushing further, putting the two cranks in the same position would be like riding one legged, only with both legs.
The motion should be funny to look at :smiley:

That’s surprisingly hard, even if your are able to ride one footed. Took me a solid 15 minutes, I thought it should only take 3 tries or so since I can ride onefooted with either foot.

Cranks at 90° are weird, feels kinda similar to riding a series of bumps that come in very regular intervals. Has a weird rhythm to it.

It has been done a number of times before :slight_smile:

A slight offset may be used to compensate leg length discrepancy.

I twisted a non-disk side 135mm SINZ crank and temporarily replaced it with a 137mm Moment crank and ended up keeping that setup for months as it did not feel weird at all.

Never really tried other combinations.

2mm? I would have been super impressed if you did! :stuck_out_tongue:

I put 150mm cranks on a 20" unicycle. It feels terrible to ride compared to 130mm cranks. With the 150s I feel the cranks get “caught” in the 12 and 6 o’clock positions, they just don’t rotate smoothly and I am always getting stuck momentarily. On a 36er… That wheel has momentum to keep rolling along. A 20" wheel doesn’t!

Btw. I never felt this problem when I had these 150 cranks on the 24" uni. The 24" seems to go well with either of the 130s or 150s. I know it’s a bit quicker with the shorter cranks, but it’s a nice and relaxed ride with the 150s.