It has been said that one cannot appreciate joy without first experiencing pain. In this same vein, I proclaim a cyclist can never fully appreciate fixed crank arms until you have attempted a ride on a set of PowerCranks.
What are PowerCranks? PC’s are a training aid aimed at improving a cyclist’s pedal stroke. A ratchet mechanism (like a free-hub) is used so that each crank arm only accepts torque in one direction. To get forward motion one must keep constant pressure on the pedal, both pushing on the downstroke and pulling on the upstroke. Each crank can be turned independently of the other. This clip shows a guy demonstrating just how far out of phase you can turn these cranks.
Last year I built up a separate bike for experimenting with PC’s. I bought into the hype about increased VO2 and delayed fatigue. I had also read horror stories of professional racers being unable to pedal around the block with them, much less complete a ride. The PC’s force the rider to use small, rarely used muscles/flexors/hamstrings to pull up on the back stroke. These muscles tend to fatigue quickly.
My first ride lasted 30 min. Initially, I thought, “This is easy!” I actually felt more powerful for just a short burst. Then reality and pain set in. I could only pedal for 90 sec before having to coast to recover. Remember when you first started riding, how painful even the smallest climbs were? Yeah. It’s like that all over again. I arrived home impossibly tired questioning why on earth anyone would ride these things. An hour later I could still barely raise foot off the floor to put on a pair of shorts.
I stuck with it. Grinding out a low cadence was the only way to make it through. Within a couple of weeks I had built my way up to an hour. Riding them was still no fun. The only solace I found was how incredible it was to ride fixed cranks again. Eventually I got used to them. I did a three hour ride one day. It still sucked. After using them for two hours per week for four months, I mostly leave them on the trainer and do a warm up and cool down on them for every ride I do on my normal bike.
Results: My Powertap has been underwhelmed by the changes in my pedal stroke. I cannot say that my VO2 or my threshold has leaped dramatically. My first race is next week, so maybe there is some untapped potential there.
So what are the benefits on normal cranks after 6 months of PowerCranks?
1. Increased cadence – Without trying my cadence jumped 8-10 rpm for any given situation. Previously, my avg cadence would sit in the low 80′s. Now if I concentrate on keeping my cadence up I can easily avg high 90′s during four hour rides.
2. Less fatigue – I feel incredibly fresh at the end of long days in the saddle. I have to believe this will be a benefit in longer road races this year.
3. Increased power @ low rpm – On super steep pitches where even my lowest gear yields rpm down into the 60′s, I have so much more torque available out of the saddle. You can pull up so hard out of saddle.
4. Fixed cranks are so much more fun after using PC’s!!! You truly appreciate how sweet normal cranks really are.
Disadvantages after 6 months of use?
1. Wallet is $500 lighter… picked up the PC’s used on ebay.
2. Pain… oh so much pain.
