Mountain bike: Difference between revisions

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A mountain bike, mountain bicycle (abbreviated MTB or ATB (All Terrain Bicycle)) is a bicycle designed for mountain biking, either on dirt trails or other unpaved environments. In contrast, road bicycles are not rugged enough for such terrain.

Mountain bikes have thick, knobby tires for extra traction and shock absorption. In recent years, front wheel suspension has become the norm and full front and rear suspension is becoming increasingly common. Some mountain bikes are also fitted with bar ends on the handlebars, but with the increase in popularity of riser handlebars (as opposed to a flat straight handlebar) fewer riders use bar end extensions. The bikes normally have 26 in (559 mm) wheels, but since 2002 some models have been available with 29 in (622 mm) wheels. (The name given to a rim diameter in inches is different from the rim's actual size.)

Mountain bikes can be classified into four categories based on suspension:

• Fully Rigid: A frame with a rigid fork and fixed rear, no suspension.
• Hardtail: A frame with no rear suspension. Usually used when the bike has front suspension.
• Soft Tail: frame with small amount of rear suspension, but activated by flex of the frame instead of pivots.
• Dual or Full Suspension: front suspension fork and rear suspension with a rear shock and linkage that makes the rear wheel move on pivots.

There are several different styles of mountain biking, usually defined by the terrain, and therefore bikes employed. All of the bikes in this category fall into one of the above four categories and bikes of each of the above style can be found almost any of the following categories.

• Cross Country (XC) mountain bikes typically have only a small amount of front and/or rear suspension (usually 80-110 mm) and are relatively light, which is achieved via the use of lightweight materials and construction in both frame and components. As a consequence, XC bikes are often less durable than other bikes. Suspension, both front and rear, is typically provided by pneumatic (air) shocks and forks, which saves weight. Some XC bike models have no suspension and use a rigid front fork, saving weight but relying more on rider skill to negotiate rough terrain. XC riding is the most popular form of mountain biking, focused on efficient climbing rather than aggressive descending. XC bikes reflect this in their lighter weights and steeper geometries than downhill bikes. However, most XC bikes are poor choices for stunts like jumps.
• Enduro (or "All-Mountain") Bikes are generally heavier than XC bikes, typically weighing between 30 and 35 pounds (14 to 16 kg). These bikes tend to feature greater suspension travel, frequently as much as 150 mm of front and rear travel, often adjustable on newer mid and high end bikes. They are designed to be able to ascend and descend mountains, integrating the climbing abilities of XC bikes with the suspension technology of freeride bikes.
• Freeride (FR) Mountain Bikes are similar to Enduro bikes, but with less emphasis on weight and more on suspension. Freeride bikes tend to have up ample suspension, with 7 or more inches (200 mm) of travel fairly commonplace. The components are built from stronger, consequently heavier, materials. They can be ridden uphill, but are inefficient and their moderately slack head tube angles make them difficult to maneuver while angled up a hill or traveling at a low rate of speed. They are effective on technical downhill trails. Frame angles are typically steeper than those found in downhill bikes. This enhances maneuverability over and around small objects. Freeride bikes typically range in weight from 30 to 45 pounds. Freeride biking usually includes some degree of natural terrain stunts such as hucking (ramping) and is usually more comprised of downhills and stunts. The most durable freeride bikes are designed almost solely for hucking and are incapable of any comfortable level of uphill travel. It is common for freeriders to frequent lift accessed riding terrain, offered at ski resorts during the off season, or simply walk their bikes uphill.
• Downhill (DH) Mountain Bikes typically have 7 or more inches (200 mm) of suspension travel. They are built as strong as possible for reliability during racing and are around 45 lbs. Due to their typically large, high gears and long, soft travel, Downhill bikes are suitable only for riding down dedicated downhill trails and race courses. The suspension is set to sag around 30% front and 50% rear of full travel, creating ample traction around bumpy corners. The head angle is often as slack as 64 degrees. Most riders who ride exclusively downhill do so in competitions or ride almost exclusively on lift accessed terrain. Due to the high speed nature of downhill riding most bikes only have one chain ring, a large bash guard and a chain guide.
• Trials Mountain Bikes are set up very specifically for the purpose of bicycle trials. They typically have no suspension at all, though some still make use of some form of it. Competition rules require bikes to have multiple gears for competition, but most riders never use their shifters. Many non-competitive riders run single-speed, choosing a fairly low-speed, high-torque gear. Most modern trials bikes have no seat at all, as the rider spends all of his time out of the saddle. These bikes are significantly lighter than almost all other mountain bikes, ranging from 15 to 25 pounds. This makes maneuvering the bike much easier.
• Dirt Jumping, Urban and Street mountain bikes lie somewhere in between a trials bike, a BMX bike and a freeride bike. They are typically very strong bikes, with 0 to 4 inches of front suspension, no rear suspension, with as many as nine gears or as few as one. Tires on these bikes are usually fast-rolling, slick or semi-slicks.
• Single-speed mountain bikes have one set gear ratio. The gearing ratio depends totally on the terrain being ridden, the strength and skill of the rider, and the size of the bike (a bike with 29" wheels often requires a different gearing than a bike with standard 26" wheels). Often single-speeds are fully rigid, steel-framed bikes. These are typically ridden by very fit individuals on mild to moderate cross country terrain.
• Mountain Cross or "4-cross racing" (4X) is a relatively new style of riding where four bikers race downhill on a prepared, BMX like, track, simply trying to get down first. These bikes are generally either full suspension with 3 to 4 inches of travel, or hardtails, and have, typically, quite strong frames. They run a chainguide on front and gears on the back. They have slack head angles, short chainstays and low bottom brackets for good cornering and acceleration.
• North Shore mountain biking originated in the hilly, slick, rocky terrain of Vancouver, Canada's north shore, thus it was coined "north shore" riding. Because of the almost, if not completely impasible terrain, riders began building bridges over swampy or muddy areas. These bridges evolved into complex, often extremely challenging, man-made stunts. Because stunts are often narrow and may require the rider to move very slowly regardless of width, north shore riding requires immense balance and bike handling skills. North shore bikes are much like freeride bikes in their geometry and downhill bikes in their component makeup. Because north shore stunts have evolved to not only include simple and complex bridges but also large drops and high speed descents through a series of stunts north shore bikes commonly have as much travel as downhill and freeride bikes, however with much more nimble and maneuverable frame designs, and often lighter-weight.

The French Velo Cross Club Parisien (VCCP) comprised about twenty young bicyclists from the outskirts of Paris who between 1951 and 1956 developed a sport that was remarkably akin to present-day mountain biking. [1]

Mountain biking started to evolve in the mid-late 1970s. At the time, there was no such thing as a mountain bike. The earliest ancestors of modern mountain bikes were based around frames from cruiser bicycles such as those made by Schwinn. The Schwinn Excelsior was the frame of choice due to its geometry. Riders used balloon tired cruisers and later modified them with gears and motocross style handlebars. They were called Klunkers. They term would also be used as a verb since mountain biking was not yet it use. They would race down mountain fireroads causing the hub brake to burn the grease inside, requiring the riders to repack the bearings. These were called "repack races" and triggered the first innovations in mountain bike technology as well as the initial interest of the public. The sport originated in the U.S. state of California, on Marin county's famous mountain, Mount Tamalpais. [2]

It was not until the late 1970s and early 1980s that road bicycle companies started to manufacture mountain bicycles using high-tech lightweight materials. Joe Breeze is normally credited with introducing the first purpose-built mountain bike in 1978. Tom Ritchey then went on to make frames for a company called MountainBikes which was a partnership between Gary Fisher, Charlie Kelley and Tom Ritchey. Tom Ritchey with his skills in frame building also built the original bikes. The company's 3 partners ran into rough times and finally fell apart at the 1983 trade show. The designs were basically road bicycle frames (with heavier tubing and different geometry) with a wider frame and fork to allow for a wider tire. The handlebars were also different in that they were a straight, transverse-mounted handlebar, rather than the dropped, curved handlebars that are typically installed on road racing bicycles. Also, some of the parts on early production mountain bicycles were taken from the BMX bicycle. The first mass-produced mountain bikes were produced by Specialized in 1983 and were copies of Tom Ritchey's frames, but they were not fillet-brazed and they were made overseas in Japan. They were configured with 15 gears.

Until recently, mountain bicycles had road bicycle style frames and geometry. Mountain biking has since become more mainstream with riding styles becoming more aggressive. Newer frames are better-designed, lighter, and stronger, with a geometry that allows for much more spirited riding over obstacles like logs, rocks, wooden bridges, and man-made ramps. Newer mountain bikes have either 21, 24, or 27 speeds, with 3 gears in the front and 7, 8, or 9 gears at the rear wheel. 30 speed mountain bikes are currently unworkable, as a slimmer 10-speed chain is not strong enough.

Many newer mountain bikes have a full suspension design. In the past, mountain bikes had a rigid frame and fork. In the early 1990s, the first mountain bikes with suspension forks were introduced. This made riding on rough terrain easier and less physically stressful. The first suspension forks had about 1½ to 2 inches (38 to 50 mm) of suspension travel. Soon after, some frame designers came out with a full suspension frame which gave riders a still smoother ride.

Most mountain bikes now feature disc brakes, which offer improved stopping power over rim brakes under adverse conditions. Their increased height (near the center of the wheel as opposed to the edge) keeps them out of puddles, and their rotors do not get bent as easily as rims do. The downside of disc brakes is their increased price compared to rim brakes and their, on average, slightly increased weight. Additionally, while disc brake pads tend to last longer than rim brake pads, maintenance tends to be more difficult, particularly with hydraulic disc brakes, which work by moving brake fluid through a hose or line to squeeze the pads together. Mechanical disc brakes, which are cheaper, work in a similar fashion to rim brakes by pulling one pad towards the disc with a cable.

The braking power of a disc brake also depends on the size of the rotor. For example, an 8-inch rotor has more stopping power than an 6 inch rotor of the same design (about 33% more). This is because the brake caliper can apply more torque with the same amount of force because the larger disk provides a longer moment arm.

Most mountain bikes use 26 in (559 mm) wheels, though some models offer 24 or 29 in (520 or 622 mm) wheels. Inch-sizes for bicycle wheels are not precise measurements: a 29 inch wheel is actually a 700c wheel, which has a 622 mm (24.48 inch) bead seat diameter. 700c is an archaic designation that persists because of its early popularity, though the diameter is 700 of no actual unit of measurement. In some countries, mainly in Continental Europe, 700c wheels are commonly called 28 inch wheels, nevertheless these wheels are equivalent to 29 inch wheels in the English speaking countries.

24 inch wheels are used for dirt jumping bikes and sometimes on freeride bikes, rear wheel only, as this makes the bike more maneuverable. 29 inch wheels were once used for only Cross Country purposes, but are now becoming more commonplace in other disciplines of mountain biking.

Wheels come in a variety of widths, ranging from standard rims suitable for use with tires in the 26 in x 1.90 in to 2.10 in (559 x 48 to 53 mm) size, to 2.35 and 3.00 in (60 and 76 mm) widths popular with freeride and downhill bicycles.

Manufacturers produce a wide variety of tread patterns to suit different needs. Among the styles are: slick street tires, street tires with a center ridge and outer tread, fully knobby, front-specific, rear-specific, and snow studded. Tires and rims are available in either tubed or tubeless designs, with tubeless tires recently (2004) gaining favor for their pinch flat resistance. Tubeless tires can also be run at lower air pressures to improve traction and increasing rolling resistance. Popular tire manufacturers include Tioga, Kenda, Maxxis, Michelin, Panaracer and Nokian.

Inherent in the sport of mountain biking is the risk of injury. Many companies now produce protective gear, often referred to as "armor," to protect against injury from crashes, mostly aimed at downhill, freeride and dirtjump riders. Armor ranges from simple knee and elbow pads to full body padding. Some companies market full body armor suits or jackets that allow the rider to remove some of the padding and/or plastic plates that protect the rider's arms. Most upper body protectors also include a spine protector that is comprised of plastic plates joined together, with foam padding underneath. Full face helmets, often resembling motocross helmets (but usually considerably lighter and with more ventilation) are required by some bike parks, although advanced riders often wear these helmets by choice, in order to better protect their heads. Backpack hydration systems such as Camelbaks are also considered to be armor by many riders for their valuable protective effects.

Some of the latest trends in mountain bikes include the all mountain bike, the 29er and the singlespeed. The "All mountain bike" is characterized by 5-6 inch (125-150mm) travel suspension bikes, able to descend well, take on very rough conditions and still pedal efficiently for climbing. The 29er bikes are those using 700c sized rims (as do most road bikes), but wider and suited for tires of two inches (50mm) width or more; the increased diameter wheel is able to roll over obstacles better and offers a greater tire contact patch. The single-speed is considered a return to simplicity-no drivetrain components or shifters, but many times require a strong rider depending on the terrain. These bikes are a celebration of the simplicity of the original mountain bikes of the 1970s at a time in which new innovations in suspension design and implementation were not yet at the forefront of bicycle technology. Many experienced riders own single-speed bikes, finding the lack of complexity and the light weight to be attractive qualities.

Another interesting trend in mountain bikes is outfitting dirt jump or urban bikes with rigid forks. These bikes normally use 4-5" travel suspension forks. The resulting product is used for the same purposes as the original bike. A commonly cited reason for making the change to a rigid fork is the enhancement of the rider's ability to transmit force to the ground, which is important for performing tricks.

Rapid popularity increase has led to the development of mountain bike oriented resorts, similar to or in the same complex as a ski resort. There parks include chairlifts which are adapted to bikes, a number of trails of varying difficulty, and bicycle rental.

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The first gearbox downhill bike was made and raced by Alex Morgan of bcd. It is was a carbon fiber frame with two chains. The first chain goes from the cranks to a 7 speed shimano nexus hub. From there the ratio is changed. Then the second chain to drive the rear wheel. The design that Alex Morgan came up with on this bike is still used today.

Frame mounted gearboxes (generally hub gears adapted to fit) are starting to make an appearance in ultra high end mountain bikes. With the gearing system protected from the elements and from impacts and the weight of the bike held low and central these offer significant advantages over conventional gear systems, particularly for extreme use. These internally geared bicycles are often also referred to as three-speed bicycles.

Nicolai is currently one of the few manufacturers of internal gearbox bikes but other companies such as GT and Alutech have bikes near production. Nicolai use a 'standard' mounting for the gearbox called the G-Boxx, which has also appeared on prototypes from Evil Bikes and Alutech.

The German company of Rohloff also manufactures and supplies a range of internal gearboxes (called the 'SpeedHub') to several bicycle manufacturers and initially also supplied Nicolai. It has since been standardized into the " G-Boxx" This system uses a separate hub above the crankshaft and needs a second set of chains. This gives revolutionary smooth shifting when compared to any external derailleur currently made. The system is also maintenance free and incredibly tough. The main disadvantages are weight and price. Contrary to popular belief the Rohloff 14 speed hub has a gearing range equal to that of a standard 9x3 (27 speed) derailleur drivetrain. Additionally the gears are evenly spaced, unlike a standard derailleur systems where the jump between gears can be inconsistent depending upon the front sprocket. The increased weight of the rear wheel can raise some complaints; the new frame-mounted designs eliminate this problem by moving the weight into the centre of the bicycle. Note that this does not imply that hub gears are excessively heavy: they typically weigh only about one pound more than traditional derailleur setups.

Several companies are working on derailleur based frame mounted transmissions, but the benefits of these are subject to much dispute. Mountain Bike Action magazine reported in October 2004 that Hayes would manufacture and sell a transmission based on the PeteSpeed design. This appears to be targeted at downhill and freeride bikes, where it has the advantage that there is no rear derailleur that can be damaged by contact with rocks and other obstacles. However, the weight compared with a traditional triple chainring and rear derailleur setup would seem to make it less suitable for cross-country riding.

Soon to be available is a rear hub, called a NuVinci CVP, with a self contained CVT (Continuously Variable Transmission) within the rear hub of the bicycle. The external appearance is that of a single-speed bicycle, with one chain ring, one sprocket and a chain tensioner. Their primary disadvantage is weight, but their placement on the bicycle ensures that they will not be damaged by trail obstacles while riding. If this drivetrain design is improved upon in the future, it opens up the possibilities of bikes with motocross style concentric chain rings and suspension pivot points, thereby improving the durability of the bike while eliminating pedal bob.

• UCI Mountain Bike & Trials World Championships
• Mountain unicycling
• Mountain Quadracycle
• Bike trials riding
• National Off-Road Bicycle Association (NORBA)
• Dirt Jumping

• Airborn
• Author
• Berg
• Brodie
• Cannondale
• Christini
• Elan
• Fuzion
• Giant
• GT Bicycles
• Iron Horse Bicycles
• Karpiel
• Kona
• KTM
• Lapierre
• LiteSpeed
• Marin
• Merida
• Monty
• Nicolai
• Norco
• Orange
• Ridgeback
• Rocky Mountain
• Santa Cruz Bicycles
• Scott
• Seven Cycles
• Specialized
• Trek
• Turner

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Wikimedia Commons has media related to Mountain biking.

• Utah Trail Info
• Hick Hucksters Organization promoting Freeriding
• IMBA (International Mountain Biking Association)
• (Mountain Bike Tales Digital Magazine)
• "A Brief History of the Mountain Bike" by Jobst Brandt
• Mountain Bike Roots - photos and race results from 1980's events
• MTBrider - Northern Ireland's mountain bike community
• Rydezilla - Rydezilla is an online community for mountain bikers that features ride scheduling, trail information, and detailed rider profiles
• MTB Bike Community. Social Networking. Bike, Downhill, Cross-Country.
• Online Guide To MTB Maintenance.