Bicycles are simple. Two wheels on a metal frame adorned with handlebars, saddle, and a bunch of gears. Yet these basic elements can be configured in a multitude of ways, creating a diverse bicycle kingdom for every pedal-powered activity under the sun. So which bike species should live in your garage?

DID YOU KNOW?
More than 100 million bicycles are manufactured each year worldwide, adding to the estimated 1 billion bicycles currently in existence.

Pedal for speed
Hit the road! Road bikes are the speedsters of the cycling family, the type you see tearing through the Alps in the Tour de France. Everything about them is geared toward maximizing velocity with minimal effort. Lightweight frames and components improve acceleration (the more you pay, the less they weigh). Drop-down handlebars and frame design position the rider in an aerodynamic posture. Narrow tires are kept at high air pressure to reduce rolling resistance. High gear ratios provide power and acceleration at speed. Road bikes perform best on smooth asphalt. They don't like bumpy streets and potholes, which can send jarring shocks to your wrists and backside. The road bike genus ranges broadly in price, from roughly $600 for a basic model to $2,000 and up (way up) for high-end racers.

Ride long, ride far
Cruise the countryside! Touring bikes are load haulers and long-distance travelers. They often resemble road bikes, with drop-down handlebars and narrow tires, but feature sturdier frames to carry gear for multi-day adventures. The distance between seat and handlebars is usually greater than on road bikes, creating a more comfortable riding position for long days in the saddle. Lower gears make full-load pedaling easier, especially uphill. Styles designed for rougher conditions incorporate wider tires, upright handlebars, and an even stouter frame. Touring bikes are a good all-purpose choice for everything from multi-day trips to bringing home groceries from the corner store; the touring class starts around $800.

Go anywhere
Head for the hills! Mountain bikes thrive in rough, uneven terrain. They feature strong, beefy frames for maximum abuse, wide knobby tires for traction, and low gears for charging up steep inclines. Most incorporate some element of shock absorption, or suspension, typically a spring-like component over the front tire. Full-suspension mountain bikes include an equivalent mechanism for the back tire and provide a much cushier ride over rough terrain. They also provide a much bigger hit to your wallet ($1,000 and up). If the back is rigid, the bike is dubbed a "hardtail" and typically costs much less, approximately $400 to $1,000. The tires and heavier weight make mountain bikes a high-friction, high-effort ride on asphalt.

Get out and about
Off to work! In between road, touring, and mountain bikes is a broad phylum of styles that incorporate elements of all three. They go by many names—commuter, urban, hybrid—but all have one thing in common. They are workhorses for the pedaltariat, utilitarian designs for regular urban commuting and around-town riding. Most are less expensive than more specialized bikes. They feature saddles and handlebars that put the rider in a more upright position, improving comfort and increasing visibility. Tire size varies; wider versions provide better traction and a more comfortable ride but increase pedaling effort. Some models feature front suspension for rougher roads and trails. One notable subspecies in this arena is the cyclocross bike, which merges a lightweight, road bike-esque frame with narrow, knobby tires; they provide perhaps the maximum versatility of any bike, from city riding to long-distance touring over diverse terrain.

Roll in comfort
Pad your backside! Recreational and cruiser bikes are for casual spins on flat or gently undulating pavement. Comfort is paramount. Large cushy seats and relaxed, upright riding positions are the norm. Some feature springy, suspension seatposts to further minimize bottom shocks. Fatter tires make for smooth riding; cruiser bikes feature oversized balloon tires for maximum stability and comfort. Recreational bikes typically feature a handful of gears, while cruiser bikes are usually only single gear—not the best choice for hills.