Bike geometry

When I was first talking about doing a triathlon with my riding buddy Rob -- he of "I could tell by the look on your back something was wrong" fame (yes, eventually I'll tell the story) -- I was talking about wetsuits and aerobars and tri-suits and --

"You like stuff," he interrupted. "You only want to do this so you can get more stuff."

There's a small -- okay, maybe not so small -- element of truth to that. I tend to like hobbies that involve gear. I can't help it. I'm a guy.

One piece of gear I've been neglecting is my bike, probably because, in recent memory, I've ridden regularly, whereas I haven't run or swum competitively in 30 years. (And I wasn't much competition back then, either.) I've been focusing on my swimming and running because they're weaker.

But my thoughts turned to the bike the other night. I have a great city hybrid, as I've mentioned before, but I really wanted to find a Web site where I could, component by component, custom-build my own bike. I'd love to give you the link, but I couldn't find one.

But I was, and am, of a mind that I might want to do something more custom for my next bike. I figured I should start by learning a little bit about frame geometry.

This is not a little bit. This article on SlowTwitch.com's Tech Center by retired bike designer Dan Empfield is pretty exhaustive when it comes to the whys and hows of bike frame design and geometry. Despite the heavy technical content, it's a breezy and sometimes very funny read. If you're fantasizing about designing and building your own bike, this is porn for you. If you're actually considering doing it, it's a necessary primer.