How Mountain Biking Works

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].

Before you head off for the mountains, it's important to learn proper riding form. When sitting on your bike, your legs should be just shy of fully extended on the downstroke (when the pedal is at the lowest point). You should still be able to apply some pressure to the pedal at this point without stretching or reaching. If the bike fits you properly, and you're using the right technique, your knees will never be locked at any point during your ride [source: Shrieves].

Once you've got your legs in the correct position, take a look at your hand placement. Your thumb and forefinger should be wrapped around the handlebars, while the other three fingers on each hand should rest lightly on your brakes. Notice that this position keeps your knuckles pointing out ahead of you, rather than toward each other like on some road bikes. Keep your shoulders relaxed and don't lock your elbows. You can place your hands as close or far as your handlebars will allow, but keep in mind that the wider your hands are placed, the more control you'll have over the bike.

Now that you're comfortable on the bike, it's time to review the basics of pedaling. Pedaling is one of the most basic mountain biking techniques, but also one of the most difficult to master. On a mountain bike, pedaling speed is known as cadence, and it's measured in revolutions per minute (RPMs). Cadence on a mountain bike is typically lower than it would be on a road bike. Lower RPMs mean less efficiency as you pedal, along with a lower speed, but also result in greater stability and endurance over longer, challenging rides. When you're first starting out, focus on keeping your cadence steady and building awareness rather than aiming for a fast speed [source: Mason].

As with all outdoor adventure sports, mountain biking will present new challenges around every turn. As you pass over difficult terrain, you'll be able to vary these basic riding techniques to help increase stability and comfort. When the trail is rocky, try sitting very low on your bike and leaning forward over the handlebars. Relax and shift your weight as you ride. Go slowly to increase your confidence, gradually building speed. Remember that the faster you ride over rocky surfaces, the more comfortable the ride will be.

If the trail is wet or muddy, focus on riding slowly, staying in control to avoid skidding. Don't brake hard when you see mud. Instead, allow your cadence to slow gradually and switch your bike to a low gear. Lean back to keep the weight off your front tires, which can keep you from getting bogged down in heavy mud.

Hills can pose their own challenges, though riding techniques will vary dramatically depending on whether you're traveling up or down. To travel up a steep incline, try lifting out of the seat slightly to increase the strength of your pedaling. If the ground is too unstable, stay in the seat and lean forward to keep the front wheel grounded. Maintain a steady cadence on hills to avoid burnout -- and to improve your chances of making it to the top.

When traveling downhill, pump your brakes instead of holding them in the entire time. Lean way back in your seat, or move your backside so it's elevated over the rear tire. This will keep gravity from pulling your body forward over the handlebars. If you do fall in this position, you'll tumble off the back of the bike instead of the front, which often results in fewer injuries and easier recovery.

Now that you've mastered the basics, let's look at some of the more advanced mountain biking tricks. Before heading out on the trails, riders should understand how to control their bikes and, more importantly, how to stop. Mountain bikes can have a variety of gear configurations depending on the type of bike you're using and the model you've chosen. Use your low gears for climbing hills, riding into the wind or for excursions that involve frequent stopping and starting. On these low gears, you'll travel a smaller distance for each revolution of the pedals, which can help with maintaining control.

When traveling downhill or on flat, easy courses, stick with the higher gears. High gears allow the bike to travel a greater distance with each revolution, which can make your ride more comfortable. As you gain more experience with your biking, you'll learn how to switch your gears for any kind of riding scenario.

One of the most important parts of riding is knowing how to stop safely. While brakes may seem self-explanatory, it can be easy to panic while out on the trail, which may lead to injury. To stay safe, practice proper braking techniques at all times, and know how your brakes operate. You should always keep your hands on the brakes so you can respond quickly to unforeseen conditions. The rear brake is usually on the right handlebar. This brake is used the most often and is less sensitive than the front brake, which is typically on the left handlebar. Always brake slowly instead of squeezing too hard. If you squeeze the rear brake too quickly, you may skid out of control, while squeezing the front brake too fast may flip your body over the handlebars. As you ride, learn to combine the front and the back brakes to stop easily and with control [source: Jones].

Once you can stop safely and control your bike, it's time to step it up a bit. Advanced mountain biking isn't simply about fancy tricks and bigger airtime. Many advanced riders can find a new challenge in learning to improve endurance, which can make riding smoother and more fun. After all, it's hard to enjoy the view when you can't catch your breath. Start by checking your cadence. The ideal cadence on a mountain bike should range from 80 to 100 revolutions per minute (RPMs). This will give you maximum speed and control while allowing you to enjoy long rides comfortably. To get your cadence in the right range, focus on pedaling in a circular motion. Think of pushing and pulling each pedal rather than simply moving your feet up and down. You'll get more distance for each stroke, resulting in a smoother ride [source: Burke].

Ready for even bigger thrills? Experiment with a few jumps and hops. Try lifting your handlebars slightly as you go over a small hill or log. This will lift your front tire and give you the feel of freeriding. If you find that you enjoy these types of mountain biking tricks, look for local freeriding or freestyling groups. They will often have courses designed so you can practice advanced tricks in a safe, controlled environment before moving out on your own.

No matter what kind of terrain you plan to ride, there are some basic mountain biking tips that riders of all levels should follow. Whether you're a newbie or a skilled rider, it's important to use the right bike for the job. The variety of bike models available can be overwhelming, as can the cost. Consider renting a bike before buying one to ensure you find a unit that you'll enjoy. When you're ready to make your purchase, don't mistake high prices for quality. A mid-range bike will work well for all but the most advanced riders. If you're new, choose a bike with a fairly simple suspension system, as more complex suspensions can make bike maintenance difficult.

Before taking your bike on the trails for the first time, get familiar with your bike on a more forgiving terrain. Take the bike out to the parking lot and ride to get used to the controls. Learn how to get your feet into and out of the pedals quickly, so you're prepared for a fall. Try measuring your cadence by counting your RPMs. Start slow, and get used to the feeling of smooth, easy pedaling. Test your breaks, and experiment with the amount of pressure needed to stop at various speeds. Practice stopping until it becomes natural and you're able to find the breaks automatically without taking your eyes off the trail or road. To mimic the feel of rough terrain, try riding over a graveled path, or up and down the curb [source: Jones].

In addition to your bike, you should be equipped with adequate safety gear when mountain biking. A helmet is a must -- it can save your life when you take a tumble. Consider knee and elbow pads, safety glasses and gloves to protect your hands.

If you plan to take a longer ride, be sure to pack plenty of water and food for energy and hydration. Small backpacks can be used to carry these items while keeping your hands free, and hydration packs make it easy to take sips of water while you ride.

Like all adventure sports, mountain biking poses some serious risks to riders. To minimize your risk, take basic first aid supplies with you every time you ride, and learn how to treat common injuries as well as more serious ones. Remember that you're more likely to get injured when you're tired, so start small and build up to longer rides. Stay clear of local wildlife when biking, and give any animals that you see a wide berth to help avoid attacks.

Stay on marked trails to avoid getting lost, and consider handlebar-mounted GPS units to help you find your way. Use up-to-date trail maps, and check your location often so you don't end up lost. Make sure you understand how to read your trail map before heading out for your ride.

According to the Shimano Research Group, more than 50 million Americans have tried mountain biking [source: Shimano]. While this seems like a huge number, it's nothing compared to the huge benefits that this sport offers in terms of physical and emotional well-being.

Mountain biking isn't only an adventure: It can also help you stay fit. Depending on the speed of your rides and the terrain you're covering, mountain biking can burn between 10 and 16 calories a minute, or 600 to 1,000 calories per hour. At that rate, biking can help you lose extra pounds or maintain your current weight. Over time, biking can increase muscle strength, improve cardiovascular health and help you build endurance that will carry over to other parts of your life. Biking just two to three hours a week can improve your lung capacity by up to 20 percent, making hiking up the stairs in your home a breeze [source: Adams].

Beyond its physical benefits, this sport also offers a number of emotional benefits that contribute to an overall sense of happiness and well-being. According to Dr. Andrew Lepp at Kent State University, outdoor activities can prevent and reduce stress, increase self-esteem, and offer a sense of challenge and adventure. Mountain biking also provides social benefits, and can help riders build a strong community [source: Lepp].

As mountain biking becomes increasingly popular, it's also becoming a major economic influence. Between local and destination biking, this sport contributes an estimated $26 billion to the U.S. economy each year. This spending includes retail sales of bikes and equipment, tourism and services directly related to expanding biking to a wider audience. A Shimano study indicates that for every one dollar spent on trail investment for biking, the United States realizes a benefit of three dollars in health-related savings as riders lose weight and get fit [source: Shimano].

Even those simply looking for outdoor adventures are sure to enjoy the many mountain biking benefits that come along for the ride.

With all the fun and other benefits that mountain biking has to offer, many people will be surprised at how much controversy surrounds this sport. Critics argue that bikers can negatively influence the local environment. Some suggest that the environmental impacts of mountain biking may outweigh the benefits, particularly in terms of trail erosion. This erosion increases storm water runoff, destroys habitats and ruins the trails for other bikers, hikers and runners. Others worry that the behavior of the reckless mountain biker is also affecting trails. These critics suggest that as riders look for new challenges, they cut into preserved lands and damage plant-life and local habitats.

Fortunately, dozens of independent studies on mountain biking and the environment, many of which are published on the International Mountain Bicycling Association's (IMBA) Web site, refute these claims. A June 2003 report posted on Wildlands CPR.com cited several different studies that found no difference between hiking and biking in terms of environmental impact [source: Lathrop]. A March 2007 study posted on the National Trails Training Partnership Web site concludes that "mountain biking is no more damaging than other forms of recreation, including hiking." This same study reported that mountain biking has far less of an impact than equestrian activities [source: Sprung].

The IMBA maintains a strong focus on protecting trails so that future generations of riders can enjoy biking at its finest. IMBA has partnered with the Sierra Club in some areas to help balance preservation needs with building and maintaining bike trails.

To protect the environment as you bike, follow the IMBA's Rules of the Trail:

These basic rules will not only help protect the environment, but will also help to build strong relationships among hikers, bikers, equestrians and other trail users [source: IMBA].

If you see a problem while on the trails, take a few minutes to help maintain the trail for other riders. To cover a muddy or wet spot, lay sticks in a criss-cross pattern across the ground. This quick fix can last for a full month or more, and will minimize erosion and protect the future of the trail. If you see a spot where riders are frequently cutting off the trail for any reason, try blocking this area with rocks or a pile of sticks and debris. This will help keep bikers on the planned trails and protect local wildlife and plants. Finally, if you see an obstacle on the trail that may require riders to take a detour, stop and remove the obstacle as best as you can to make it safe for other riders. This will also help keep bikers from veering off the trail to by-pass the obstacle [source: Adams].