cranks and rpm and bikes

I have been reading the threads on crank length theory and have not seen any direct reference to rpm. I have been riding a uni for 30+ years and racing bikes for 20+ years, and have just recently started to consider different crank length options for my unicycles which have 140s and 150s.

Obviously a uni has 1 to 1 gear ratio, which is about as low a gear I use for climbing while racing a mountain bike. For maximal efficiency 90 to 110 rpms is my optimal aerobic range, and max power is obtained between 140 and 160 rpm. At 6’1" I prefer 177.5mm cranks for road and moutain bikes and 172.5mm for fixed gear or track bikes.

I can’t see myself buzzing around on my uni at 100+ rpm for any significant distance, which is my comfort zone on bike.

What kind of rpm are some you guys spinning, and for what kind of riding?

Re: cranks and rpm and bikes

I think maximal efficiency for a particular RPM depends on your crank length- I would not feel very efficient trying to spin a set of 170’s at 140rpm, but I regularly spin 140rpm on 100mm cranks without too much effort. Your comfort zone/aerobic threshold is definitely crank length dependent.

I need to check out some video footage of uni racing or coker speed riding. I have only watched trials and muni stuff.

I have some videos from last summer’s Nationals here:

Because we do not have the luxury of gears, we talk less about rpms as they are not a constant. You “rpm” as fast as you can, and look for the right wheel and crank size to help you do it better!

If you race on the track, until we get the 700c class up and running, you’re on a 24" wheel with 125mm cranks.