I plan to hop my 36er up a flight of 66 stairs as another birthday challenge, so I was wondering if crank length would make a difference? Since the cranks are horizontal when hopping it seems the main difference would just be in the distance between your feet, from front to back. If I hop the same steps on my feet, either forward or sideways, my feet would be parallel. So I’m curious if anyone thinks shorter cranks, like 110s-125s might be more of an advantage than longer cranks in the 150-165mm range?
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I kind of thought it might be the opposite. It seems to me that long cranks give you more leverage to correct for any imbalance front to rear while hopping.
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Longer cranks would be more stable, but also more weight… ideal crank length would just be whatever your most comfortable on and use to the most… I think tire pressure would have much more of an effect on this challenge than crank length.
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Yes, that was my initial assumption. I have hopped that flight of stairs on my 36er several times and always used 150s, but I started wondering whether shorter cranks — which bring your feet closer together, forward and back, and more closely mimic how you would hop on foot — might be more appropriate. Guess I’ll just have to try it to find out.
Cheers,
Terry
Interesting thought. I’d personally think having enough leverage to stabilize when you get of balance outweighs any biomechanical gains from shorter cranks. At least in a “normal” range of crank lengths (let’s say 110mm to 160mm).
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Maybe the best compromise would be to go as short as possible without sacrificing control. Trial & error time. 
I wouldn’t think it would make any difference, the best performance is most likely going to come from what you are most used to doing.
If I was going to do it, I’d attach 66 big-ass helium balloons to my waist.
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Cheers,
Terry
Your hopping skills are clearly superior to my own. Whenever I have tried hopping on my 29/36 I’ve always had better success with longer cranks like 150mm. I can hop on 125mm reasonably well too but I can’t hop with 110mm at all.
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Cranks “actually flex” so think of the diving board effect.
Longer cranks “if flexing” at the right frequency will increase the momentum for the unicycle rise.
Quick test:
a.) Try bunny hopping with your feet on the hub.
b.) Try bunny hopping with your feet on the cranks.
What do you feel?
Short stumpy cranks are for rotational speed, not leverage and power.
Anyways, happy anniversary Terry and keep on riding. Why don’t you call the local news reporter, I’m sure they will want to come out, again!! You are a southland Legend!!!
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I’d think that shorter would be more efficient. The longer the crank is that more horizontal force (wasted energy) you put on the pedals.
If you think of extreme ranges, with zero length cranks all your effort is vertical. However the longer the cranks are, the more wasted energy is pushing the feet/pedals away from the hub. Put you feet 3’ apart and see how high you can jump and compare that to jumping with the feet together. It is clear that you could jump higher with feet together.
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This was my initial reasoning, but I’ll just have to do a little trial and error and see what works best. Thanks everybody for your input!
Haha, thanks slamdance. The local news has already covered a lot at this point so I doubt they’d be interested. Maybe if I make it to 100 and try a ride-my-age it might spark some interest. 
That’s obviously true when taken to extremes. I don’t think it matters that much though as even with 170mm cranks it’s still a rather narrow stance. Taken to the other extreme, you’d be taking about hopping on a BC wheel, which are nearly impossible to ride in the first place, much less hop repeatedly on with no forward movement.
I think what’s more key here is control rather than hopping power. Notice that trials riders tend to favor some of the longest cranks they can put on a 19”.
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Very interesting. I’ll have to look into that.
I think 137mm is largely the norm for trials and street, (but I could be wrong), and that’s pretty darn long for a 19" wheel.
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Yes, that seems to be the default (138mm also) crank length for most 19" trials, however the KH trials has dual 117/137mm cranks.
True. However, I was wondering if they favor long cranks for jumping stability purpose or for pedal grab max reach?
Any trial rider that can chime in ??
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Another question would be whether cranks with or without q factor would be the best choice for hopping. Pretty sure trials unis have zero q cranks. Might be that there’s more stability when your feet are closer to the wheel, as in uni racing for example. Also why it’s harder to ride an actual uni wheel (with hub and cranks) as a UW, compared to an actual UW.
Regarding q factor, I’d prefer a large pedal platform. It just seems to give you the best of both worlds.
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