How can I improve my cadence on the 26 and 36"? More sprints? What worked for you? Any suggestions welcome.
Without changing the Crank lengths.
practice practice practice. go to a school running track and ride that for a while
Ride with someone faster and try and keep up with them 
Yeah, trying to keep up with 3 very fit guys riding 29ers while I was riding a 26er definitely helped increase my cadence!
Advice often given to roadies is to consciously take leg weight off the rear pedal. How this works on a uni is anyones guess…ouch
Crank length plays a part, I can’t spin my 165mm cranks on my 36" in muni mode for crap, struggling to hold 10 mph average, going to the 137mm hole I can hold 12-13 and even 14mph at a push
Handle bar may also help and is something I keep thinking about.
But really it is just practice as has been said, I ride with the Endmondo app running on my phone tracking my riding and have it telling me my minute mile time so I will constantly try and beat my previous mile time or my fastest ever mile time, this means i have to go faster and therefor spin faster but I am not thinking about the spinning as it sorts itself out naturally, I feel that concentrating to much on the actual act of spinning will just make it worse (like unicycle riding in general) just think about going faster or beating a time
Ride a lot.
Ride as far as you can without stopping. Develop that muscle memory.
During the ride, do short bursts of 5 or 10 revolutions as fast as you can.
Ride a lot.
Pro bicyclists train where I train all the time.
You want to increase your speed, right?
They have advised me to focus not simply on pushing down during the down stroke, but continuing to pull back (on a pedal with teeth) until its 90 degrees behind you in the revolution. If you look at your foot circle as a pie, the only place you have minimal press is the quarter slice just before your foot reaches the highest point of the circle. It’s the next best thing to being hooked onto the pedal. It allows BOTH legs to work during MORE of the foot circle.
Also, prevent the slight wobble side to side, if you run through water, your tire track should be absolutely straight, not snaky.
Once you get the technique, then work on power sprints, full out! Push through the burn!
What I’ve found useful:
- stay relaxed, you should have very little tension in the upper body and upper body movement
- keep as little pressure on the pedal as possible. Let it feel like it’s ‘floating’. Just enough pressure to keep yourself on the unicycle and adjust balance.
- get a standard class unicycle for practice
- lose weight. Beefy legs are no good for spinning fast.
What BillyTheMountain said goes a long way. If you work on peddling in a circle instead of mashing the peddles straight down like most people tend to do you should see some improvement.
That’s perfect, Mike. +1 
Yes.
Considering weight being throwed fore and back (not only up and down), be sure that you have tried different adjustments of the height of the seat.
Easy said. A thing that might should not be said loud, riding a bicycle with proper pedals, only one foot clicked in at time, will force you to push and pull the whole circle (its not a point to ride with high cadence when doing this). Keeping in mind that the power on the pedal should be equal the whole circle (while relaxing the upper body as much as possible), you will soon get the “round” feel. Transfering to a uni, your legs will be able to do work allmost 75% of the circle. Still keeping in mind not pushing the pedal hard down, you might fleet, with high cadence.
Thought I would simply go faster when I got a schlumpf and could keep the same cadance… boy was I mistaken!!!.. I think the biggest thing is to learn keeping your balance at a higher speed… 2 years ago I basically hit a wall when I tried to go over 10mph for any distance on either G29 or fixed 36 … now I have the same problem at 12mph… at least its improving… but slowly 
I agree with ken. You get speed by relaxing.
I have started doing more track bike riding and what I have found is that I am actually slow in the high cadence sprints. What I excel at is the big gear sprints, particularly uphill. Not what I would you would have expected. I am working hard on my high cadence sprints. Look out dusseldorf!
Ken? Sam? Have you found the same?
Roger
Roger … if I remember correctly last year you averaged 169!!! your going to go faster???
Yes
I was on the road Uni (ungeared 29 w/125’s) for the first time in a long time Thursday afternoon and after 30 minutes or so my spin started getting much better. Speed was up and not too much wiggle. My road set up has a higher saddle and I ride holding the seat (no handle) which helps keep everything quiet.
Seat height is key if cadence is the only consideration. Not the case off road.
Back on the muni today I really noticed the difference and cadence was notably higher.
Like Roger my old road bike is set up with a track style fixed wheel and 165 cranks for summer riding. This helps my spin a lot and I’ll be 140 rpm plus down hills and ‘relaxing’ is the only option.
30 years ago I used to do devil-take-the-hindmost sprints on that fixed wheel bike with the local roadies and was never the first eliminated despite being seriously out geared. Old muscle memory paying dividends on the Uni.
Make sure you don’t cramp up going crazy fast spinning down hills!
pax
I don’t believe in the whole pulling up on the pedal business. It’s a myth in biking, and even more so in unicycling.
Almost all power is generated on the downstroke, with the upgoing leg relaxing to allow the hamstrings and gluteus muscles to elongate. You might get some power out of your hip flexors and quads pulling up, but I think it would only be useful in a high power sprint. Over long distance, that extra muscle contraction would add to fatigue for very little extra power output. I’ve tried it on my bike and it seems to waste energy.
At high cadences, it becomes even more superfluous. You want the upgoing leg to relax as quickly as possible before the next phase of contraction. To be actively pulling up is going to slow your cadence down.
That’s not the same as ‘pedaling in circles’. You want a smooth pedal stroke without actively pulling up (which makes things choppier). I do that on a unicycle by putting very little pressure on the pedals on the upstroke- it should feel your foot is floating on the pedal as it comes up.
Indeed - I was going to suggest exactly the same issue. I am going faster on my Schlumpf, but only ~20% faster than on the same size unguni (admittedly that is also with longer cranks - at some point I might get the confidence to go back to the same length as on the unguni). Though I have managed to average almost 13mph on a (non-flat - had to change down once) loop after 3 months of riding it 
I agree with all of Gizmoduck’s advice. Increasing the cadence depends on being able to maintain a certain speed without too much stress or vibration. It’s a gradual process. Everybody has experienced when you hit a speed where you tend to bounce up and down, or otherwise jangle about and it’s very inefficient. Sometimes pedaling a little faster can get you out of that. But if not, concentrate on smoothing everything out.
Ultimately you want to only be working the muscles required to pedal fast. Your upper body should not be working hard at all. Different crank lengths can make a big difference. You will tend to do better with some lengths than others. Mostly this is because those are lengths you are used to. But it’s possible to pedal very quickly and efficiently even with 175s. I remember trying to keep up with George Peck at one of the early MUni Weekends; he with 175s and me with 150s or maybe even 140s. I couldn’t catch up!
Yes, your feet need to make good circles. Anything other than round, and your feet will come off. When pedaling fast, the power stroke kind of takes care of itself. If your feet are on the pedals, you’re doing pretty well in making those circles. You can only apply “useful” power on the downstroke and across the bottom.
Also I don’t know if ankling is useful at really high cadences. For me it always seemed to reach a point where it was too fast for the ankles to maintain the rhythm, and my feet were more static at those very high speeds. I used to be able to get my Track unicycle up to 17.5 mph, which is pretty darn high RPMs!