Mountain bike

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A cross country mountain bike race

A hardtail mountain bike

A mountain bike, mountain bicycle (a.k.a. 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 aren't rugged enough for such terrain.

Mountain bikes have fat, knobby tires for extra traction and shock absorption. In recent years front 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 a recent trend in riser handlebars (as opposed to a flat straight handlebar) fewer riders use bar end extensions. The bikes normally have 26 in (559 mm) wheels although 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. See below, at Tire Sizes.) The larger wheels are said to roll better over obstacles, but critics cite increased rolling resistance and a lack of variety in aftermarket tires and forks (which are becoming more readily available). The larger wheel diameter also increases rotational weight, resulting in slower acceleration.

1 Designs
- 1.1 Discipline oriented bike designs
2 History
3 Modern Bikes
- 3.1 Suspension
- 3.2 Disc brakes
4 Tire sizes
5 Protective equipment
6 Latest trends
7 Future technology
8 See also
9 External links
- 9.1 Manufacturers

[edit] Designs

Freeriding on a Hardtail freeride bicycle

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

Hardtail: frame with no rear suspension, often has a front suspension fork
Fully Rigid: sub-type of hardtail, with a rigid fork
Dual or Full suspension: front suspension fork and rear suspension with a rear shock and linkage that makes the rear wheel move on pivots.
Soft Tail: frame with small amount of rear suspension, but activated by flex of the frame instead of pivots.

[edit] Discipline oriented bike designs

There are several different styles of mountain biking, usually defined by terrain, and bikes to suit those styles. 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 tend to have only a small amount of suspension (usually 80-100 mm) on the front and/or rear, and are fairly light. This is achieved via the use of lightweight materials in both frame construction and components. As a consequence of their lightweight material they are often weaker 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 at all and use a rigid front fork; saving weight and relying more on rider skill to negotiate rough terrain. XC bikes are often as light as 20 pounds (9 kg), or as heavy as 30 pounds (14 kg). XC riding is one of the more common types of riding and in its extreme form can be entirely uphill, hence the lightweight rigs. Cross country terrain typically is considered as having as many, or more, ascents than descents and does not include any kind of stunt riding.
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, often as much as 150 mm of front and rear travel, often adjustable on newer mid and top range bikes. These bikes 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 Mountain Bikes are similar to Enduro bikes, but with less emphasis on weight and better suspension. Freeride bikes tend to have up ample suspension, with 8 or more inches of travel fairly commonplace. The componentry is built from stronger, consequently heavier, materials. Freeride bikes are designed to be more versatile than any other bike. They are somewhat capable of being ridden uphill; however, their moderately steep head tube angles make them difficult to maneuver while angled up hill or traveling at a low rate of speed. yet also 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, with uphill travel usually for the purpose of reaching this terrain, hence the necessity for a freeride bike to be able to travel uphill somewhat efficiently. The most durable (and expensive) 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 Mountain Bikes typically have 8 or more inches (200 mm) of suspension travel. They are built as light as possible for racing and range from 45-35 lbs. They are very strong, and due to the typically large, high gears and long, soft travel, 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. Competition downhill mountain bike racing is where most mountain bike technology is innovated, as most bike manufacturers sponsor a number of riders. Downhill biking is just as it sounds, downhill. 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. Downhill mountain biking is the most high profile category of competition biking.
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, and as many as nine gears and as few as one. Tires on these bikes are usually fast-rolling, slick or semi-slicks.
Single-speed Singlespeeding is as much a life style as it is a type of mountain bike. A singlespeed is a mountain bike with 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 singlespeeds are fully rigid, steel-framed bikes. These are typically ridden by very fit individuals on mild to moderate cross country terrain.
Mountain Cross or "4X racing" 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 unridable terrain, riders began building bridges over swampy or muddy areas. These bridges evolved into complex, oftentimes 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, such as those by manufacturer Norco are much like freeride bikes in their geometry and downhill bikes in their componentry 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.

[edit] History

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 late 1960s and early 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. Riders used balloon tired beach cruisers and modified them with gears and motocross style handlebars. They would bomb (ride fast) 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 wasn't until the late 1970s and early 1980s that road bicycle companies started to manufacture mountain bicycles using high-tech lightweight materials. Gary Fisher is normally credited with introducing the first purpose-built mountain bike in 1979. The designs were basically road bicycle frames 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 and were configured with 15 gears.

[edit] Modern Bikes

A full suspension Mountain Bike

Until recently, mountain bicycles had road bicycle style frames and geometry. Mountain biking has 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. Also, many riders are now jumping on mountain bicycles and taking on a more BMX style of riding. Newer mountain bikes have either 21, 24, 27 or 30 speeds, with 3 gears in the front and 7, 8, 9 or 10 gears at the rear wheel.

[edit] Suspension

Many newer mountain bikes have a full suspension design. In the past, mountain bikes had a rigid frame and a rigid fork. In the early 1990s, mountain bikes started to have front suspension forks. This made riding on rough terrain easier on a rider's arms. 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 smoother ride throughout the ride.

Newer suspension frame and fork designs have reduced weight, increased amount of suspension travel, and improved feel. Many lock out the rear suspension while the rider is pedaling hard or climbing, in order to improve pedaling efficiency. Most suspension frames and forks have about 4 inches (100 mm) of suspension travel. More aggressive suspension frames and forks made for downhill racing and freeriding have as much as 8 or 9 inches (200 or 230 mm) of suspension travel.

Many riders still prefer to ride a hardtail frame, and almost all mountain bicycle riders use a suspension fork. Well-known suspension fork manufacturers include Magura, Manitou, Marzocchi, Fox, Rock Shox, and (to a lesser extent) White Brothers. Some Cycle manufacturers also make their own suspension systems to fully complement the bike set-up. Specialized have done this to great effect with their 2007 Enduro range.

Full suspension mountain bike technology has made great advances since first appearing in the early 1990s. Early full suspension frames were heavy and tended to bounce up and down while a rider pedaled. This movement was called pedal bob, kickback, or monkey motion and took power out of a rider's pedal stoke — especially during climbs up steep hills. Input from hard braking efforts (known as brake jack) also negatively affected early full suspension designs. When a rider hit the brakes, these early designs lost some of their ability to absorb bumps — and of course this happened in situations where the rear suspension was needed most.

The problems of pedal bob and brake jack began to be solved in the early 1990s. One of the first successful full suspension bikes was designed by Mert Lawwill, a former motorcycle champion. His bike, the Gary Fisher RS-1, was released in 1990. It adapted the A-arm suspension design from sports car racing, and was the first four bar linkage in mountain biking. This design solved the twin problems of unwanted braking and pedaling input to the rear wheel, but the design wasn't flawless. Lawwill's design was hindered because it couldn't use traditional cantilever brakes and had to use disc brakes. A lightweight, powerful disc brake wasn't developed until the mid 1990s, and the disc brake used on the RS-1 was its downfall.

In 1991, while working for AMP Research, (owned and run by another motorcycle racer named Horst Leitner) Karl Nicolai designed a bike that utilized the four bar linkage design and accepted a normal cantilever brake. This bike was initially marketed under the AMP brand and a version came to the mass market as the Specialized FSR. It became the standard by which all other full suspension designs were judged for the next decade. Specialized bought several of Leitner's patents in May 1998 and other manufacturers (ironically now including Nicolai himself) must now pay licence fees to Specialized for the use of the 'Horst Link' suspension design.

The amount of travel on full suspension bikes has steadily increased with 100mm now acceptable for XC race designs and up to 150mm on trail or enduro bikes. For freeride and downhill even more suspension travel is the norm. Technological advances have enabled these machines to be of similar weight and cost as high end hardtails of the mid 1990s.

Several different full suspension designs are now well established in the marketplace.

The simplest — the Single Pivot — which bcd, Morewood, Orange, Cannondale, Santa Cruz, Mountain Cycle, and even cheap department store bikes still use.

The Four Bar (and its variant the Faux bar) use several linkage points to activate the shock. A 'true' Four Bar will have a pivot behind the bottom bracket, one in front of the rear wheel drop out (this pivot being the venerated "Horst Link"), and one at the top of the Seatstays. A Faux Bar will be similar but will have a pivot above the drop out instead of in front of the drop out (ie no Horst Link and no patent problem). The importance of this one pivot is heavily debated with supporters on both sides of the debate. Four Bar designs include Norco "VPS" bikes, almost all Specialized bikes, Kona, Ellsworth, KHS, Turner (although their new 06 Flux has lost the Horst link), and Ventana.

The VPP (or Virtual Pivot Point) is a linkage designed bike that is built to activate the suspension differently depending on what inputs the suspension has received. The VPP design is currently owned by Santa Cruz who also licenses the design to Intense. Yeti Cycles have created a unique rail system to eliminate pedal jacking The DW-Link is another design licensed to Iron Horse and Independent Fabrications. Giant's Maestro is yet another design. Patents have drawn definite lines among the manufacturers.

The Soft Tail, which relies on the flexing of the rear triangle and a rear shock placed in line with the seat stays, is one of the simplest designs introduced. Soft tail designs are a variation of the original Amp Research Mac-Strut design (technically a 3 bar suspension design). The design is currently falling out of favor because its main benefits — simplicity and firm pedaling — can both be achieved with other designs with more, and possibly, better suspension. It does not do well over small ripples or any kind of large bumps.

A full-suspension mountain bike with a single-pivot suspension.

Almost all of the full suspension designs have been able to benefit from advances in new suspension technology. A stable platform shock is the latest design to hit the market and reduces unwanted bob. There are several different designs that have come to market with Fox, Manitou, Rock Shox, and several smaller companies now in the fray.

Specialized, long an innovator in the bicycle industry, introduced the Specialized Epic, featuring the Brain^(TM) shock. This makes the frame a hardtail until a bump comes from below. This turns the bike into a fully active full-suspension bike until the lack of additional bumps resets the frame to rigid mode. The Brain shock, produced by Fox Racing Shocks, has an inertial valve that makes this possible. It was this technology that enabled the Specialized Epic to become the very first full-suspension bike to ever win the World Cup.

The VPP (Virtual Pivot Point) system used by Santa Cruz and Intense, also claims to have reduced the problem of pedal bob. Soon after the VPP was introduced, the creation of the Progressive Suspension 5th Element rear shock (based on Currnut's platform damper) near the beginning of the Millennium allowed riders to adjust almost any frame, regardless of design, to be pedaled without the pedal bob that plagued earlier designs. Other companies have followed Progressive's lead (mainly Manitou with its SPV system based on the 5th Element and Fox's ProPedal which uses a shim stack rather than an air pressurized valve) and a revolution in suspension design is underway. However, these 'intelligent' shocks always have to compromise between their resistance to bob and performance with small bumps.

Many think the tried and trusted technology of the four bar linkage with a comparatively simple shock still offers the best performance. Ironically, as shock manufacturers compete to have the latest 'pedal platform' technology four bar riders are pushed to the most expensive dampers on which it is possible to switch off the pedal platform! With the rise of more complicated shocks and a larger market share of full suspension bikes mountain bike suspension tuners have now arrived. It is now possible to have shocks tuned to individual rider's desires.

[edit] Disc brakes

Most mountain bikes now feature disc brakes. Disc brakes offer improved stopping power and modulation over rim brakes. Their increased height keeps them out of puddles, and rotors don't get bent as easily as rims do. The downside of disk brakes is their increased price compared to rim brakes and their slightly increased weight. Also, while the disc brake pads tend to last longer than rim brake pads, maintenance tends to be harder especially with Hydraulic brakes, which work by moving brake fluid through a hose or line to squeeze the pads together. Mechanical brakes, which are cheaper, work in a similar fashion to rim brakes by pulling one pad towards the disc with a cable. Most disc brake companies, among which are Avid, Shimano, Hayes, Tektro, Raceface and Magura, also produce rim brakes.

A Mountain Bike Disc brake

Disc brakes on mountain bikes are still moving forward. Hope have recently released their "Moto" brake which is an oversized single-pot design, but the real improvement has been in the rotor which is not only a floating disc, but is also vented as well. This means that it runs 15% cooler than a standard floating rotor, virtually eliminating brake fade on long descents and meaning that there is always plenty of bite. Also the braking power of a disc brake depends on the size of the rotor. For example, the Hayes V8 8inch rotor has 30% more stopping power than the V6 6inch rotor making it more usful when speeding down a hill. That said most riders will not notice the difference between the two unless they push their brakes to the limits.

[edit] Tire sizes

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, and are predicted to be the choice wheel size on Downhill Bikes within a few years by some. The first production 29 wheeled dh bike is made by bcd.

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 tyres 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.

[edit] Protective equipment

Part of the thrill of this sport, besides the beauty of being in the country, is the risk of a spectacular wipe-out. This can be due to equipment failure or mis-judgement on the rider's part. Many companies (Fox, RaceFace, Dainese, 661 etc...) 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.

[edit] Latest trends

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 2 inches (50mm) width or more; the increased diameter wheel is able to roll over obstacles better and offers a greater tire contact patch. The singlespeed 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 1970's 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 ride singlespeed 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.

The rise of downhill biking has led to the development of chairlifts which are adapted to bikes. The obvious example is Whistler Mountain Bike Park, which opens during the summer at the popular Canadian ski resort Whistler Blackcomb. Similar parks usually offer a number of trails of varying difficulty. It is often possible to rent bikes suitable for that terrain at the resorts, thus an unexperienced downhill rider can get a feel for downhill biking without spending the $3000 to get the bike.

[edit] Future technology

The first gearbox downhill bike was made and raced by Alex Morgan of bcd bcdracing.comIt 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.

Nicolai gearbox freeride bike

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.