How Mountain Biking Works

Physics of Mountain Biking

As you begin to participate in mountain biking activities, it's helpful to learn or review the physics of mountain biking to gain an understanding of how this sport works. By understanding what kind of forces you're up against, you can learn how to choose the right equipment for your ride -- and even how to reduce your risk of accidents.

Mountain bikers face a variety of forces that can bring thrills or spills, depending on how prepared you are for dealing with them. Bikers will experience tremendous speed along with the pull of gravity as they traverse hills and inclines. Mountain biking physics is a delicate balance between the weight of the bike and the speed and stability of the rider. The forces on both bike and rider increase when jumping over rocks and other obstacles, and can rise exponentially when attempting big tricks during freeriding. Finally, bikers should understand how to deal with rough terrain, including rocks, mud and loose soil on the trails.

Mountain bikes are equipped with certain features that help protect the rider and the bike from the demands of off-road riding. They have strong, sturdy frames to hold up against the forces of mountain biking. Larger brakes are used to prevent brakes from wearing out after heavy use. Tires are very wide and knobbly to increase traction and stability, and handlebars are placed close to the body to help riders maintain better control over the bike. Mountain bikes typically have complex suspension systems to help absorb some of the shock from rough terrain, jumping and quick descents.

To counteract these forces and learn to ride safely, riders should choose a bike based on the type of terrain they plan to cover. A downhill or full-suspension bike is equipped with a heavy-duty suspension in both the front and rear of the bike. The suspension helps to minimize the teeth-rattling impacts of speeding downhill over rocks and other obstacles. Downhill bikes also have a large, heavy frame to improve durability, and a low top bar so riders won't get tangled in the frame during a fall. Large disc brakes are used in place of smaller V-shaped pads because of their longer lifespan.

Those looking for a bike for all-around riding should look for a cross-country or hardtail bike. Hardtail bikes are so named because they have no rear suspension system. The small front suspension minimizes the impact of rough terrain, while the mid-size frame offers a balance of strength and low-weight. These bikes are faster than a downhill bike, but are less tough and stable. Their reduced weight makes it easier to ride them uphill and over a broader range of terrain [source: Mason].