Fixed freedom

This morning I went for my longest-ever fixed gear ride. I did a little over two hours on the fixie, dodging the season’s first snowflakes over the rolling hills of Canton and Stoughton. I enjoyed the ride, though getting out the door was a trial. When I headed to the basement, I knew I had two quick tasks to accomplish before I could head out: I needed to mount a computer on the fixed-gear bike, and I had to flip the rear wheel around from the freewheel side to the fixed gear side. Together, these should take about five minutes. Here’s how it actually went down:
8:35am – Felt a quick flush of satisfaction when I found the computer mount without having to rummage through a pile of junk
8:37 – Flush started to fade as I realized I only had one of the three zip ties I needed to secure the mount to the fork.
8:38 – Back on top of the world after I improvised with a little vinyl tape.
8:40 – Realized the screw that holds the computer bracket on the handlebar is missing. The flush started to feel more like embarassment. In a flash I decided to cannibalize the screw from another bike with the same kind of mount.
8:45 – After much fumbling with screwdriver, mount is secure. I decided to pump up the tires before removing the rear wheel and flipping it around. Good thing, since I ripped the valve stem out when I removed the pump. If that had happened after I had taken the rear wheel out and put it back again, I would have been really bummed.
8:53 – New inner tube mounted on rear wheel.
8:55 – Bike is ready to go, but I had to dash upstairs to get the chain grease off of hands.
9:00 – Finally out the door.
With that frustration behind me, I was free to enjoy two hours of Just Riding Along Without Coasting. The fall colors aren’t as spectacular as I’ve seen them in previous years, but even with the snow it beat the heck out of another day on the trainer.
After the ride I just had to sit down and figure out how fast my legs moved at max speed. My top recorded speed was 27.3 MPH, or 43.9 Km/h. The bike’s wheel circumference is nominally 2096mm, so at 43.9 Km/hI was doing about 349 wheel revs per minute. The bike had a gear ratio of 2.625, so my max pedal RPM was about 133, which is fast but not blazing (I’ve heard that track racers will hit 170 in sprints).
So, how fast were my feet moving? The crank has a diameter of 345mm, 133 Revs/min * .345 m/rev * 3.14 = 144 m/min = ~8.6Km/h = 5.18MPH. Which is not nearly as fast as it felt.