So you've seen those bikes with the thick wheels and thought, "What's up with that?" Maybe you've heard friends talk about the fun of off-road biking, seen people trekking into wooded areas and parks with bikes in tow, or even watched the more adventurous types explore mountainous terrain on bikes that look like the two-wheel equivalent of a Hummer.

Maybe the thought of hiking on a bike appeals to you, or maybe you just like the idea of being able to bike through town without worrying about every pothole and bump the way you would with a "traditional" road bike. If you fit any of the above descriptions, chances are mountain biking appeals to you and you'd like to find out more about this great sport.

Okay, let's start with the basics, beginning with - surprise, surprise -- the bike itself. The first thing you'll find is that buying a bike is decidedly more complex than it once was. There are a bewildering and dazzling array of bikes to chose from, ranging from the three-speed Schwinn of your parents' generation to futuristic designs with prices approaching that of a Mazda Miata. How to choose?

First, let's define the term "mountain bike". Simply put, mountain bikes are regular bikes with big tires. That definition would certainly offend purists, but for the beginner it's "good enough for rock and roll."

Mountain bikes are the sport utility vehicles of the two-wheel world. Like SUVs, they go where their traditional brethren will go, but they can also do a lot more. And, to continue the comparison, if what you're after is a sleek, smooth, racing machine designed for speed on even terrain, they're not the choice to make. (You wouldn't pick a Jeep for high-speed highway driving, either). The larger wheels and generally heftier design allow them to survive uneven terrain, dirt, bumps, potholes, and all the other vagaries of off-roading that would cause a wipe-out on a traditional thin-wheeled road bike. Which in turn, makes them a lot more versatile.