What size cranks on 20" Nimbus

Looking for answers to what should be a simple question. I am going to buy a Nimbus 20" trials. ( the Gremlin Chrome ) I want to try my hand at some tricks, but also do some riding around town. Not interested in way out tricks, just some simple stuff right now. My thinking is, would a longer crank arm be a bit more harder to get going ( sorta Kinda ) but once going be less hard to keep up a decent speed? Where as a smaller crank length would make me work more to keep that same speed? Not so worried about the trick end with the crank length. Bigger less turns, smaller more turns? Help!!!

The “standard” seems to be 137mm. They are short for street but not too short for trials. They also seem to be good for flatland. As for riding around, 137mm are great, not too fast and out of control but quick.


Both crank lengths will rotate with the same frequency. What changes is the total distance of the pedals and their linear speed. Longer cranks require you to move your legs over a greater distance during the rotation of the wheel, this means that you have a greater level of control over the wheel’s rotation. However, for each rotation your legs must move faster making it more difficult to keep the wheel rotating quickly.

My recommendation would be for 125 mm cranks. They are probably the shortest (i.e. fastest riding) cranks which still give enough control and stability to make hopping tricks comfortable for a beginner.

137’s would be a bit harder to spin quickly and are really only an advantage when doing rolling gaps or hoping on rocks.

114’s will make the unicycle feel like a gliding form of transport, but be prepared to have the unicycle shoot out from under you when trying some tricks.

I’d agree with the recommendation for 125mm cranks. I recently got a 20" trials with 137mm cranks but my use for that uni is hopping around and learning tricks. If I also wanted to use it to ride around the neighborhood I’d have gone with 125mm cranks.