Not all tandem bikes are created the same. There are tandem bikes designed for different things. Tandem bicycles that are built for cruising and have a single-speed are better suited for smooth surfaces, like paved roads, sidewalks, or bike trails. Limited hills and uneven terrain. Most tandem bikes will fall into this category. Tandem bicycles that have front wheels suspension and multiple gears can be used off-road on gravel, brick roads, and dirt. Though off-road terrain is not highly recommended for long distances because bumps in the road can throw off the simultaneous pedal motion needed to keep the bicycle going. If you are going to ride on rugged terrain, be sure to be an experienced tandem bike rider with a bike made specifically for bumps and curbs.