At Andrés' repeated urging, I bought a road bike last week. All my previous bikes have been mountain bikes, so this one has taken some getting used to. It took a few rides before I was able to turn without feeling like those tiny tires were going to lose traction and I was going to fall in a tumbling heap of Dan parts.

What's more, this is a single speed fixed-gear bike, which presents its own set of novelties. The first time I took it out for a ride, I got up to speed and then reflexively stopped pedaling, expecting to coast. The bike politely informed me that it wanted me to keep pedaling, and I was nearly launched out of my seat.

As I'm getting used to it, I'm really liking the smooth, easy ride of those thin, treadless tires, as well as the simplicity and the direct feeling of being mechanically connected to the road. It's a lot like driving a stick-shift car versus an automatic — you just feel a lot more directly involved in the working of the machine, rather than being a simple passenger along for the ride.

It feels incredibly light, too. This bike is at the very bottom end of the road bike price range, so it has a steel frame, rather than the aluminum frames of more expensive bikes. It weighs 20 lbs, which I'm sure is far heavier than the $1000 bikes, but it feels like a featherweight compared to the mountain bikes that I'm used to handling. Which is good, because I live on the third floor.

I really like how you can brake simply by applying reverse pressure on the pedals. I don't even keep my hands down by the brake levers anymore — I do all my speed control with my feet, and it feels perfectly comfortable. It's tiring as hell, though.

And oh, man, do I get tired. I think the fixed gear has been pointing out even more dramatically how out-of-shape I am. The first time I rode the bike, I took two laps around the apartment complex parking lot and I was exhausted — I barely had the energy to carry the bike up the stairs.

The rear wheel has a flip-flop hub, which is threaded on both sides so you can install a second cog on the other side of the wheel and simply flip the wheel around when you want to use it. The chain has to be re-tensioned etc., so it's probably not the kind of thing you want to do at a whim, but it's very nice to have that flexibility. I ordered a single speed freewheel cog to mount on the other side of the hub — if the fixed gear gets overwhelming, I'll have the option of switching to the freewheel cog for a bit of an easier ride. The freewheel I ordered also has one more tooth than the fixed gear I've got now, so it'll be a slightly easier gear ratio as well.

So this is it — I've made the investment on a bike, so now I've got to ride it. It hasn't been a problem so far. I've been really excited about it, rushing down the stairs to take another five-minute ride as soon as I've caught my breath from the last one. Sure, it's pathetic that I get tired so quickly, but I figure if I keep riding this frequently, that will improve quickly.

I think this is one instance where my tendency to get way too into a hobby might actually help. When I get really excited about something—be it photography or music or astronomy—I'm constantly eager to engage in the activity. In the case of photography it often gets frustrating because it requires creativity; I'm often consumed by an overwhelming desire to go take pictures, but have no ideas about what to actually take pictures of. Whereas with a bike, creativity isn't a factor. When I'm overwhelmed with a desire to get out there and use my bike, I can just go do it. I don't need to wait for inspiration to strike. That tendency towards obsession may work in my favor.