One of the most common responses I get when I tell people I race a one-speed bicycle is "Why?" There are many ways to interpret this response. If I'm talking to a non-cyclist, they probably meant to say "You mean a pedal bike? Why don't you ride something with a motor?" or "Wouldn't you rather sit on the couch and watch TV?" If I'm speaking to a cyclist, however, the response is triggered by a more involved thought process. "Wouldn't you go faster with gears?" "Why would anyone choose to make it harder?" Of course they are right, a rider who is fast on a single speed bike should be faster on a geared bike. I, however, am not. I've seen evidence that I am not alone in this. So the big question, again, is "why?"
A bike with only one gear has the frictional and weight advantages of a shorter chain, no derailleurs, and no dueling rings. A bike with multiple gears, however, has the efficiency advantage of letting it's engine spin a perfect cadence nearly all the time regardless of terrian. Seems like an unfair fight.
Here's where I think the meat of the issue is: We are all thinking and feeling beings. I don't ride single speeds, or any bicycle, just because the technology is efficient. I don't even ride (usually) just to get from point A to point B. Most of the time, I'm just going around in loops of varying size and shape, only to end up back at the same spot, dirty and tired, faced with the task of cleaning the bike again. How efficient is that? Riding is something we do, most often, for how it makes us feel, during and after. The exertion and the challenge feel good, and the resulting fitness really feels good. There are several ways our brains and emotions interact with the riding experience, which are just as powerful and important as the physical factors like bike weight, body fat and aerobic threshold.
I get pleasure from riding my single speed Surly. I enjoy riding it more than my geared bike which cost much more. I almost always go faster on the Surly.