Flats vs Clipless Pedals

Power comparison using flat pedals with mid-sole foot placement versus conventional "clipless" clip-in pedals

by Jerry Nolan

When I took up the sport of triathlon. I soon discovered I had a problem with my calf muscles cramping after transitioning from the bike to the run. To solve the problem, I decided to minimize the use of the calf muscle by placing my foot mid-sole on the pedal. Naturally I had to switch from "clipless" clip-in pedals to flats to do this. My initial impression with the mid-sole foot placement was "Wow! I feel so much stronger this way." I rode mid-sole for the duration of my triathlon career, about six years, then continued to ride this way for the next four years. I took a lot of grief from my roadie friends ranging from disbelief to being told I could gain 30% more power by switching to clip-in pedals. In Fall of 2019 I decided to try clip-in pedals again. My reaction was "Wow! I feel so much stronger this way." Okay, what's going on here? I decided that I'd better conduct a scientific experiment to see what's going on.

I felt that the mid-sole foot placement meant more power because the calf muscle is the smallest and weakest muscle in the power chain of the cycling stroke. Most power comes from larger muscles in the body, namely, the gluts, hamstrings, and quads. I thought the small calf muscles were a power bottleneck for the larger muscles. This was the reasoning behind my sticking with mid-sole flats for so long.

When I switched back to the clip-in pedals, I seemed to be ride stronger than ever, but I learned long ago not to trust my judgement in such matters. I needed to be scientific. I designed an experiment where I would ride one day with mid-sole flats and the next with clip-in pedals. I could quantify the results with a heart rate monitor and power meter and then use statistical analysis to see if there was any significant difference.

I used Garmin Vector 3 power meter pedals to measure power. My plan was to ride my Specialized Roubaix on a Kurt Kinetic Road Machine fluid trainer for three months, December, January, and February. For the mid-sole foot placement, I used a pair of Flypedals. Flypedals are adapters that convert clip-in pedals to flat pedals. They are designed for bike commuters who don't want to deal with two pairs of shoes when commuting to work.