One of the more curious types of bicycle is the tandem bicycle, more commonly known as a bicycle built for two. The tandem bicycle has two seats -- one seat behind the other -- two sets of cranks for pedaling, and two handlebars for stability and control. Only the front set of handlebars move, as the person sitting in front is responsible for steering while the person in the rear is responsible for added pedaling power and balance. While the tandem bicycle has been around for many years, it has evolved in recent decades to accommodate not only the casual couple strolling around town, but also racers and more serious bicycling enthusiasts.
The tandem bicycle has a much longer wheelbase than a regular bicycle and can therefore be more difficult to control. In addition, because there are two people on the bicycle instead of one, the extra weight can cause the bicycle to shift in various directions more severely. Therefore, while riding a tandem bicycle, it is important for both riders to communicate with each other and work together to maintain balance. The tandem bicycle requires that both riders work together not only for balance, but also for power: because there are two cranksets on the bike, both riders must pedal in unison.
There are several different varieties of the tandem bicycle. The most common is the cruiser-style tandem, which is perfect for strolling around town. In recent years, the tandem road bike has hit the scene, mimicking the design and purpose of a road racing bicycle featuring skinny tires and aerodynamic geometry. This allows riders to either race their tandem bicycle or use it for training purposes.
The newest addition to the tandem bicycle family is the tandem mountain bike. This tandem mimics the style and geometry of a typical mountain bike but allows for two riders. The tandem mountain bike -- like all tandems -- has a much longer wheelbase and reinforced frame for strength. Tandems in general tend to be very heavy because of the extra frame material, parts, and accessories, and they are therefore somewhat inefficient for racing purposes. But for the general enthusiast looking for a different approach to a fun activity, a tandem might be a worthwhile investment.