The Lizzyville Coaster: Inception

If you hang out in the city you can't escape noticing these odd looking bikes, often straddled by even odder looking riders. Unlike the bike your midlife-crisis afflicted dad just bought, which is described by a plethora of buzzwords (OCLV, V-brake, Octalink, SUP, SPD, Exa-Drive, Hyperglide, SiS, ISIS, Hollowtech, every year there's a new few) the beauty of these bikes lies in their singularity of purpose. Designed for the Velodrome (a bicycle racetrack), they can only do one thing: go very fast on smooth, flat surfaces. They don't have any braking mechanism--save for jamming backward on the pedals, since a fixie by definition can't coast--because during a race where riders are speeding upwards of 40mph inches away from each other, one person stopping suddenly can end disastrously for all.

The evolution of these tuned, sleek machines took a sudden turn when someone decided to bring one out onto the streets: a decidedly more hostile environment for both the bike, which is accustomed to well-maintained surfaces, and the rider, who has to deal with cell-phone talking Starbucks-carrying drivers oblivious to anything not blinking on a Blackberry screen. Numerous pitfalls notwithstanding, there are many valid reasons why fixies are great for city riding:

• Less to worry about while riding. With no gears to change, you'll never think about them! Besides, in most flat cities low gears aren't necessary.
  
• Less likely to get stolen. This is less true now than it was 10 years ago, thanks to the boom of fixies and the ingenuity of the aftermarket part vendor devising ways to make something as simple as a chainring look precious. (The word "bling" comes to mind.) In the past though, a bike on the street with one speed was usually a piece of crap, the money hits were the carbon-titanium-aluminum kitchen sinks.
  
• Easier maintenance. I don't care what people say, maintaining a multi-speed bike, especially one with index shifting and a compact 9 or 10 speed drivetrain is a lot of work. Something's always scraping, getting out of true, or not shifting on a dime. Worse, even if you manage to find a sweet spot, all it takes is a small bump against a parking meter or a Chihuahua getting caught in the chain to send it all to hell. Not so with a fixie! All you have to do is check your chain's in good condition, and grease the bearings once a month or so.
• Good workout. Stopping the bike with your legs is hard work! I've heard this is detrimental for real riders because it teaches bad habits and messes with the circularity of your stroke, but for regular folk I see no such drawbacks.
• Teaches excellent riding technique. This is what fixie riders elaborate upon ad nauseam, unfortunately they're right. If you decide to get on a bike without brakes and take it out into the street, provided you're not flattened in the first few days you begin to develop a heightened awareness for the road. You stop looking a body's length in front of your tire and start analyzing activity two, three blocks ahead. If you watched too many action movies as a kid, you also start imagining targeting reticules floating around your vision, an HUD displaying pertinent tactical information and a three-dimensional map overlay (think Google Earth).
  

One must also keep in mind that it's possible (recommended) to ride a fixie with a front brake and a single brake lever. This is often colloquially referred to as the "oh shit handle" or some variant thereon.

Following this brief and altogether too opinionated introduction to fixies, let's turn out attention to the particular bike we'll be assembling.

DESIGN GOALS

The rider is a 5'8" female, about 115lbs. Thanks to her litheness I can relax a bit over the abuse the bike will take, although that's only half the picture as the bike will be ridden around Brooklyn and Manhattan. As the introductory vehicle to single speed riding, I'm opting to go for a single speed freewheel, which means you can coast. There are two reasons for this. One, the initial fixed gear experience is disconcerting. It's like one of those volunteer psychology studies you did in college, where some grad student grasping at a meaningful dissertation topic puts you in a room and make you play a driving video game except the screen's reversed so left means right and vice versa: completely doable with all your concentration, except after 10 minutes you have a splitting headache. Being a gift, I'd like the initial experience to be something other than "nauseating". I dunno, something positive, like "collarbone breaking". Kidding! The other reason I don't want to make it a fixie is that sometimes you want to use the bike to get somewhere without expending a lot of energy. Call me out of shape, but when I ride my fixe I always work up a bit of a sweat braking all the time. Maybe I have poor fixie riding technique, and I should really be coasting through everything totally disregarding the rights of way of others. Whatever. The point is, in the interest of efficiency it's going to be coaster. I'll use a flip-flop hub so that when curiosity strikes there won't be any technical obstacles to going fixed.

To choose the right frame, we need to analyze the rider's body geometry. Fortunately I have a good photo for that purpose. With judicious application of Photoshop, we arrive at the following result:

Help, I'm a ghost!

As I said, this is going to be a freewheel affair. As such, it's commonplace to use a ratio slightly lower than comfortable on a fixed, since going downhill fast won't require spinning the legs. I have a spare 16 tooth freewheel, so I need to determine a chainring size to mate that. I get by just fine with a 48/16, which gives an even 3:1 ratio. The rider in question hasn't done a lot of riding recently, so to make things a bit easier in the beginning I'm going to go with a 42/16 or 39/16. Since 39 is often the second chainring on a multi-speed crankset, I'll go with 39/16, which yields a ratio of 2.43:1. To get an idea of the cruising speed, if we assume there's going to be a 700x28 tire, the approximate wheel circumference is 84 inches. If we further assume she's going at an 85 rpm cadence (she's a runner, and the optimal running/cycling cadence according to my triathlete friends is around 90) that's going to be 85 revs/min × 60 mins/hour × 2.43 rotations/rev × 84 inches/rotation ÷ 12 inches/foot ÷ 5280 feet/mile = 16.5 miles/hour. Okay that's a tad slow, but we're in New York, taking it easy never hurt anyone.

THINGS YOU'LL NEED

Let's go over the BOM (bill of materials). For the structure, we'll need:
A frame, fork, headset, stem, handlebars, seatpost, saddle.

Then the drivetrain, which is usually a whole complicated affair in a multi-speed bike, is reduced to the fundamentals in a single-speed:
Cranks, bottom bracket, chainring, chain, freewheel, pedals.

And this is going to be driving the wheels, which are comprised of:
Rims, rim tape, inner tubes, tires, spokes, hubs.

Next, we need some way to stop, so we're going to need:
Brakes, brake cables, brake levers.

Finally, the finishing touches:
Bar grips/bar tape. Basket. Decals. Lock. Lights.

Find out how to procure these items in the next installment, when we tackle the caprices of eBay!