Bicycle any ground

The bicycle any ground , shortened VTT , or bicycle of mountain (in English mountain bike , shortened MTB ), is a bicycle intended for a use any ground. It robust and is adapted to the breakable grounds. In their jargon, the vetetists also use the term spad to indicate their VTT, probably in reference to biplane S.XIII regarded as a floret of aviation.

The competition

The VTT is a discipline dating from the Années 1970 coming from the United States (it should be noted that the precursors of this sport are Parisian beginning of the Années 1950: the Bicycle Cross-country race Parisian Club).

Several disciplines exist, the principal ones are the trial, the descent, the descent marathon and the cross-country race. The latter is an Olympic discipline since 1993 and appeared three years later with the Olympic Games of 1996 with Atlanta. One also counts several more directed disciplines spectacle like the dual slalom or the 4 cross-country race, inspired by the Ski and the Snowboard.

Other disciplines, the street, the freeride and the dirt seem with competitions. They are disciplines coming from BMX.

The street is practiced exclusively in urban environment. It is a question of using furniture with disposition.
The dirt consists in carrying out figures at the time of the jump of a large bump on a série.
The freeride is as for him more one frame of mind that a discipline. One will seek more the ludic side of a technical path, than the performance and the output suitable for the cross-country race. That is not without pointing out the ski or the snowboard.

There exist tests of endurance, over 12 midnight, disputed by shift teams like those of Spa organized since 2001.

Although very little mediatized compared to cycling on road, there however exists of many compétions of VTT: local and regional qualifications, isolated races, national and international championships, etc Including/understanding the popularity of the VTT, the manufacturers and equipment suppliers invested themselves in the competition while engaging of the professional pilots.

The excursion

The practice of the excursion with VTT is a widespread sport. The French federation of cycling sets up marked out routes especially adapted to excursions VTT. There are some for all the levels. These routes are recognizable by the formed beacons of two discs and a triangle indicating the direction to be taken. the color of this logo varies according to the type of course,

yellow logo: small communal excursion (it is generally a loop, on a limited territory);
red logo: seldom numbered, inter-commune excursion even interdépartementale or great crossing, it is not a loop;
maroon or dark logo: it is about a site classified natural park it is doubtless a loop.

The color of the numbers on the beacon indicates the difficulty of the course:

toll-free number: very easy course. In general short and easy at the same time, accessible to the children;
number blue: easy course. Longer, up to 20 km or some difficult passages, sometimes accessible to the children;
red number: , difficult course. Superior to 20 km with several difficult passages, that requires a physical fine shape;
black number: very difficult course. They are really difficult, long circuits (35 km and more) and techniques.

It is requested from all the hikers to close again the barriers which they open to pass, to completely clean their zones of snack or wild camp-site before setting out again. He is advised, even for excursion, to carry a helmet, he is of course advised to prepare his route with if possible a topographic chart , for very left as a recluse or out of the marked out circuits. If you only leave, carry your cellphone, your chart and your compass because in the event of accident it will be easier to ask of the assistance or of the help if you can define your position.

Moreover many clubs of VTT affiliated to the federations, organize all the weekends or almost marked out excursions accessible on all the levels for a participation going from 3 to 5 €.

Itinerant excursion

Several courses of itinerant excursions exist in France:

the Great Crossing of the Massif Central (GTMC) which rejoins Clermont-Ferrand with Sète in 10 days. The course is marked out on the ground and of the guides supplement description.
the Great Crossing of Vercors which rejoins Grenoble with Die is the first part of the route Grenoble - Sisteron of the Ways of the Sun. Several courses are available for the GTV.
the Great Crossing of the Jura (GTJ) which as its name indicates it cross-piece the Massif of the Jura of North to the South by traversing the departments of the Doubs, of the the Jura then of the Ain.
the Ways of the Sun also called Great Crossing of Préalpes, are traversed either in the North-South direction of Grenoble to Sisteron, or in the West-east direction of Valence (Drome) with Gap.

Disciplines

The VTT is declined in various practices - or disciplines.

Dirt

The dirt is a practice close to BMX, in the fact that the goal is to carry out jumps (ex: camel, double, table, drome, jump flat) which is noted by a jury and that using natural obstacles or not. But contrary to BMX, the practice of the dirt is carried out with a generally semi-rigid VTT (which has a fork with damping but not back shock absorber); indeed this last would dissipate the energy of the forces of pédalage. The VTT are slopping , i.e. the higher tube is prolonged in the tube connecting the tube of saddle to the bases (it is very tilted backwards). This practice thus consists in carrying out figures in the double bumps or other tables which compose the field of bumps (or dirt tracks). The bicycles weigh between 12 and 15 kg and have a fork before very hard in the neighborhoods of 100 mm clearance or less.

Some examples of typified VTT Dirt:

Cannondale Drives out
Specialized P.3
Giant STP (created by Jeff Lenosky)
NPJ Haussmeister
Specialized P.2
Candida titanium
Scott Voltage

Street

The street , or urban assault , approaches BMX. It is a question of rolling in a park or of adapting the city, while making use of urban furniture (walls, staircases, benches, low walls, trees etc). The executives of VTT street are very slopping , generally out of steel chromo 4130, and are often assembled with wheels of 600 mm (24 inches), which makes them more handy. The equipment is tiny room to bare essential: no the Shifting track (singlespeed), and brake only with the back (singlebrake), but it arrives sometimes that they are assembled without brakes (brakeless). The forks have between 80 and 100 millimetres of clearance or have a rigid fork quite simply, as in BMX and Trial. The bicycles of Street weigh between 12 and 16 kg. It is perfectly possible to make dirt with a bicycle of street and vice versa. Even the professionals of marketing did not separate their ranges street and dirt yet.

Some examples of typified VTT Street: Blk Markt Mob, Union Street Bikes Molly, 24 Moon

Trial

It is a question of crossing obstacles (rocks, tree trunks, etc). The sequences are done has very low speeds. Sometimes even, the trialist remains in balance on an obstacle, jumps on another obstacle, stabilizes his bicycle and so on. Sometimes the bicycles used have a very small framework without saddle, a long bracket and are equipped with powerful brakes, generally with disc or hydraulic shoes (for a highher degree of accuracy with the touch).

two alternatives are possible:

the bicycle trial, with wheels 20 inches in diameter (used for the children to begin, but also by the adults). The pedals are protected by a shoe because the ground clearance is low.
the VTT trial, with wheels 26 inches in diameter.

Some marks are specialized in the trial, such as Koxx and Monty.

Excursion and cross-country race

Marathon

The courses of marathon are slightly less less technical than those of cross-country race, but especially much longer with sometimes 5 hours of continuation on the saddle. The proportion of all-suspended bicycles is thus more important than in cross-country race country, for reasons of comfort mainly.

Enduro, all mountain

This discipline is generally practiced in mountain. It is a question of climbing the slope before descending it. The solidity-clearance ratio/weight-output varies according to the bicycles. Indeed, more the framework is solid and more there is clearance plus the bicycle will be effective in the uneven negative ones; but that will result in to weigh down the bicycle and to make him lose output (the more there is clearance, the more the bicycle “pumps”, to see low), which will make it less effective in the uneven positive ones. The bicycles of enduro weigh between 14 and 17 kg and have a clearance generally ranging between 120 mm and 170 Misters.

Some examples of typified VTT Enduro: Specialized Stumpjumper FSR (enduro light, 120mm of clearance), Scott Ransom (Enduro average, 160mm with before and 165mm with the back of clearance), Scott Nitrous (Large enduro, limit freeride, 170mm of clearance)

Furnace-cross-country race or 4X

Descent

Freeride

Geometry of the very suspended VTT

As for the fork, the addition of a suspension to disunite the movements of the aft wheel of the bicycle has several objectives:

to offer a better contact between the wheel and the ground, to have an optimal motricity even on the escarpés grounds.
to give to the pilot a higher comfort of use by filtering part of the vibrations resulting from the ground and while avoiding transmitting them to the saddle.
to allow a more permissive and approximate piloting, or to authorize a more committed practice on fast courses and victims while keeping the control of its machine.

Of course the implementation of a suspension on a tallies must be considered to limit the undesirable effects, such as the effect of pumping, which dissipates part of the energy emitted by the pilot at the time of the pédalage in a movement of from top to bottom framework, in particular during the rise of slopes at uneven fort. The suspended executives have a second disadvantage: the weight, more important than that of a rigid framework, which strongly limits their use within the framework of competitions XC or the weight is a determining factor on the not very technical races. A too flexible suspension will give a “soft” framework and little reagent, but a great comfort thanks to a filtering of the asperities of the very full ground. On the contrary a very hard suspension will bring a very sharp and reactive behavior, going until approaching a rigid framework, but will imply a comfort of second choice logically. The whole is to find the compromise ideal according to the practiced discipline, associated with a technology of suspension and an adapted geometry.

History

The all-suspended bicycles did much progress since their appearance with the beginning of the year 1990. The first all-suspended executives tended to be very prone to the effect of pumping. The effects of a powerful braking deteriorated them also qualities of a suspended whole. Indeed, as soon as the cyclist touched the brakes, the bicycle lost its capacity to absorb the shocks.

These problems of pumping and undulation to braking were partly solved with the beginning of the year 1990. One of the first effective bicycles all-suspended was conceived by Mert Lawwil, a former champion of motor bike. Its bicycle, Gary Fisher RS-1, appeared on the market in September 1990. It had adapted the multiaxis suspensions of the sport scars, and it was the first “furnace bar linkage” in VTT. This design made it possible to eliminate the problems with the pédalage and braking. But the design of Lawwlil was not perfect, indeed, this last could not use the v-brakes and could accommodate only disc brakes. It is not that in the middle of the 90 qu years ' appeared light and powerful disc brakes. The disc brakes of the RS-1 were thus its principal defect.

In 1991, whereas he worked for AMP Research, Karl Nicolai designed a bicycle which used the system furnace bar linkage and which accepted the v-brakes (brakes out of V). The bicycle, was marketed under mark AMP and a version reaches a mass production under the name of Specialized FSR. This model became a reference. Specialized repurchased several of the patents of Nicolai and now, all the users of furnace bar linkage pay rights to Specialized (including the inventor of the Nicolai system).

Since, the geometries, like the shock absorbers, did not cease evolving/moving to offer increasingly satisfactory qualities.

Types of geometry at present

The Mono-pivot

This system is of a great simplicity. It calls upon a triangle postpones simple and interdependent (of a part, without articulations) composed of the bases, stays, and of a stem replacing the tube of saddle. This triangle is connected to the remainder of the framework (front triangle) via one only and single articulation, located at the level of the case of pedals. For reasons of output (to limit the effect of the tension of chain resulting from the pédalage on the movement from the suspension), this articulation is generally positioned just with the top of the case of pedals, with the height of the second plate. It is used by Morewood, Orange, Cannondale, Trek, Mountain Cycle, and is usually used on the bottom-of-the-range models of supermarket.

The Furnace bar linkage (and its alternative the False bar)

This advanced system is based as its name indicates it on a " triangle" back either made up of three but of four elements, with an aim of carrying out a deformable parallelogram which will activate the suspension. These elements are:

a tube replacing the tube of saddle of the triangle before
the bases
the stays
a rod located at the lower part of the aft wheel, between the stays and the tube of saddle.

These elements are associated with the four following joints to allow this deformation:

high pivot, which carries out the connection between the tube of saddle and the rod. This connection can be present as well in front of as behind the tube according to the implementations, but is found most of the time just in lower part of the horizontal tube of the front triangle.
low pivot, located between the tube of saddle and the bases. This pivot is in the majority of the case located behind the case of pedals.
pivot of wheel, which establishes the link between the bases and the stays. The position of this pivot dissociates the Furnace Bar linkage False Bar: for the Furnace Bar this pivot (called Horst Link , under patent Specialized) is present on the bases, in front of the aft wheel, which dissociates the back wheel axle of the circular motion of the bases compared to the front triangle. On the contrary, on the False Bar this same pivot is located at the top of the back wheel axle, on the stays, which gives to the aft wheel a movement interdependent of the bases, and thus circular compared to the front triangle, with the manner of the mono-pivots. The False Bar is not thus any more a Horst Link is not of this fact concerned with the problems of patent.
pivot of rod, between the top of the stays and the rod, closes the parallelogram.

The Furnace bar linkage include the bicycles Norco " VPS" , almost all the Specialized bicycles, the Kona bicycles, Ellsworth, and Turner

The VPP (Virtual Pivot Not - Not of virtual pivot)

It is a geometry which varies the operation of the suspension according to the way in which this one is activated. System VPP belongs for the moment to Santa Cruz which also sells it in Intense. Lapierre holds also an important patent with its system FPS2 which equips almost all its all-suspended. The Yeti bicycles use a system of rail (see photo higher of Yeti 303) reducing pumping. One will note also the Maestro system of Giant. The patents of each manufacturer limit much the production of the other manufacturers.

The Tail Software

This system, deprived of articulation, rests on the back flexibility of the bases. This geometry starts to fall in disuse because these principal qualities (simplicity, reliability and lightness) are now reached by other geometries, more effective on the successions of small shocks and the large jumps. This geometry is used in cross-country race, and called having upon materials of the precise mechanical properties (titanium is very usually used). The Software trail is used by Cannondale, Vitus.

Technologies of shock absorbers

Almost all the geometries of all-suspended bicycles profit from progress in the technology of the shock absorbers themselves. The geometry of the framework and the positioning of the points of inking of the shock absorber will modify considerably the way in which this last will behave. Indeed, the ratio " height of rise of the wheel arrière" /" compression of the amortisseur" is specific to each implementation of suspension, and which more is this ratio can evolve/move during compression thanks to the use of a specific geometry, or with the addition of additional rods to obtain a nonlinear compression.

The principal manufacturers - of which Fox Racing Shox, Manitoban, Shox Rock'n'roll, DT-Swiss - shock absorbers create limiting pumping.

Composition of a shock absorber

A shock absorber is composed of two parts: a spring, which store energy during the compression and which restores it then, and a system of damping, charged to dissipate this energy to avoid an indefinite swinging of the suspension. there

the spring, systematically composed before of a metal spring, gradually left place to shock absorbers with Air on the models requiring little clearance (lower than 180 mm) for various reasons, of which the possibility of easily regulating the force of the rebound by modifying the pressure of the principal room. According to the model of suspension, required hardness and the weight of the pilot the pressure necessary can go from 3 bar to more than 8. The metal spring is all the same preserved on the executives at strong clearance (200 mm) such as those used for the descent, with an aim of having a better rigidity and a linear compression, and also equips the majority with the bottom-of-the-range models of large surface for obvious reasons of cost.

the system of damping is with rare exceptions close implemented by an oil mixing. During compression/relaxation of the suspension, a stopper having weak openings crosses a cylinder filled with oil, located in the central part of the shock absorber. This movement forces oil to pass in the openings, and thus dissipates the energy stored by the spring. The index of viscosity of oil as well as the size of the openings (sometimes adjustable without having to dismount the shock absorber on the current models) modify the behavior deeply.

Dual Air

The search for a compression increasingly more effective and more significant on the small asperities forced the manufacturers to propose specific implementations in order to dissociate competitors. Rock Shox proposes on the majority of its range of the versions Dual Air, which lay out in addition to the traditional spring formed by air under pressure in the principal room, of a secondary room whose behavior is opposite. This second room thus tends to compress the spring, giving him a better sensitivity mainly on the very small asperities.

Shock absorber with extension

Scott Bicycle developed for its Genius (model XC) a shock absorber functioning contrary to the conventional direction. Indeed, instead of being compressed, this shock absorber is extended on the suspension of such kind to being stretched at the time of the recess of the aft wheel, giving a better behavior to the spring air.

Lock

To gain nervousness on the travelling passages, of many shock absorbers have an external serrated roller of locking, which closes the openings of the system of damping, and returns of this fact the completely ineffective suspension. By pushing this principle of Lock further, certain marks, such as for example Fox Racing Shox, developed shock absorbers multi-position which offer behavior radically different by modifying the position from a valve, which influences on the size of the openings of the system of damping. The operating processes of the system of damping are then optimized for the nervousness, or comfort, or a maximum clearance, or an optimal motricity, etc This system obliges the pilot all the same to have to modify the shock absorber while rolling, which is not inevitably easy matter to achieve according to the position of the shock absorber on the framework. To solve this problem, certain manufacturers propose in option an ordering of blocking of the back shock absorber to the handlebar, with the manner of the fact that it is done for certain models of fork.

Brain

Specialized presented in 2003 Specilazed Epic, having the shock absorber Brain (French brain). This shock absorber - manufactured by Fox - uses a spring simple Air having a room of compression, but is very particular in the operation of the system of damping him even. Indeed, even if it takes again the system of lock present on much of model competitors, activation or the desactivation of the lock is left here with the load of a mass of inertia, positioned in a vertical tube. This runner (called valve of inertia) manages the opening of the system of damping while letting pass more or less from oil according to its position. By defect it is maintained by a mechanical spring so as to complete completely, thus depriving the bicycle of its suspension and then offering a behavior close to that of rigid. The movement of pédalage of the pilot will not change absolutely anything in this state, and the effect of pumping so much dreaded is removed. as soon as a shock occurs, the inertia of the runner makes him compress the mechanical spring, and opens the passage of oil then. The suspension then finds the operation of a traditional framework very suspended. Once the asperity of the ground deadened, the spring gradually repositions the runner opposite the opening, blocking the suspension again. The first bicycle equipped with this technology had the role to attack the closed circle of semi-rigid typified X-Country by proposing a system of suspension which offered even higher identical performances (better motricity on the breakable passages, better control of the trajectory). Besides Epic counts among the few executives all suspended used in international competitions (Olympic Games for example). Unfortunately, the surplus of weight caused by this suspension limited its democratization.

Piloting

To benefit from its VTT, it is necessary to know the bases of piloting. In cross-country race , one can summarize them as follows:

support: the vetetist uses 5 fulcrums: 2 with the handlebar, 2 with the pedals, and the saddle;
attitude: to always look at far in front of oneself, to be able to anticipate the difficulties;
trajectories: a gold rule to the approach of a turn: after having adapted his speed, one takes the turn “outside-interior-outside”, which means that one approaches the turn outside, one then comes to touch the interior with the cord, then one sets out again towards outside. This technique makes it possible to keep a broad radius of curvature, therefore a good adherence;
turns: to always keep the external pedal in low position, the interior pedal being thus raised, and thus not being likely to hang; one exerts a pressure on the external pedal, to maintain the VTT on his trajectory;
assembled:

position: it is necessary to advance on the saddle, and to approach the handlebar; for the particularly difficult rises, with little adherence, the vetetist rises saddle and sticks himself to the handlebar (technique of the “plated dancer”);
anticipation: it is advisable to change gear before the effort; in VTT, it is necessary “to roll flexible”: to always pedal at the same rate/rhythm;

descent:

position: it is necessary to take off of the saddle (to even lower the saddle), and to place its basin of before behind according to the situations; the feet are on the pedals (use your legs like shock absorbers, therefore be neither too stiff nor too soft), cranks with the horizontal one. While placing the weight on the back, one reduces the nose gear wheel for less undergoing the obstacles - with the detriment of the control of the direction. In the same way, while placing the weight on the front one, one gives adherence to the direction - but one is constrained to better anticipate the trajectories to avoid the obstacles.
braking: should be adopted a flexible braking: neither blocking, nor mollesse; the usual distribution is 60% with before and 40% with the back; One council to use braking that when one for of requires really, that makes it possible to take turn more quickly and to make better times, the majority of people believes the limit of adherence much more close it is not it actually (obviously it is necessary to be at ease with his mounting);

technical passages: in front of a difficulty (stock, stones, etc), the vetetist rises on the pedals, and keeps the cranks with the horizontal one; the arms and the legs semi-are bent; Speed is adapted to the encountered difficulty; thus, it is possible to control its bicycle; once the speed of adapted approach, one should not any more fix the obstacle but look at far in front of (the trajectory follows the glance); during any technical passage, one constantly keeps two fingers on the brakes and there is always necessary to remain concentrated on the ground.

Federations of cycling

There exist two main confederations of cycling in France :

the French federation of cycling.
French federation of bicycle touring.

The FC organizes the championship of France of VTT, like various competitions. The FC deals only with excursions.

There exists also the French Union of laic works of physical education, which organizes competitions and training courses of VTT.

Some marks

Bianchi, Brodie, Cannondale, Canyon, Commencal, Cubic, Diamond, Decathlon, Devinci, Giant, WP, Intense, KHS, Kona, KTM, Lapierre France, Sailor, MBK, Merida, Merlin, Mountain Cycle, Msc, Nakamura, Nicolaï, Norco, Orange, Orbéa, Qbikes, Rocky Mountain, Santa Cruz, Scott, Specialized, Sunn, Titus, Trek, Turner, Vario, Viper, Vitus, Yeti, etc

Champions

French champions

AsCaroline Slipper 12 times world champion of descent
Julien Absalon:

Champion of France 2004,2005,2006,2007
Champion of Europe 2005,2006
World champion 2004,2005,2006,2007
World cup 2006
Olympic champion cross-country race in 2004

Miguel Martinez, Olympic champion cross-country race in 2000
Nicolas Vouilloz, 10 times world champion of descent in 11 years
Cédric Gracia, champion Red Bull Rampage 2003, World cup of descent and 4-cross-country race.
Fabien Barel, victorious of the championships of the world of descent 2004 with Gets and 2005 in Livigno, champion of Europe, France. It gained a sleeve of world cup of descent in 2005. He is vice-champion of the world 2007.
Sabrina Jonnier, world champion of descent 2006.
Emmeline Ragot, world champion junior of descent 2002 and 2003.
François Gachet, world champion of descent 1994, champion of Europe 1995, victorious world cup 1994
Eric Barone, Recordman of the world from speed with VTT on snow to 222,223 km/h and ground to 172,661 km/h

Belgian champions

Alain Crickx
Filip Meirhaeghe: champion of Belgium 2006
Bastien Peralta: champion of Belgium 1989
Niko Vink

Canadian champions

Marie-Helene Prémont: 2nd 2005-2006, Money with the Olympic Games of Athens
Roland Green, world champion 2001-2002

Swiss champions

Nino Schurter :

world champion Junior 2004, U23 2006;
World cup U23 2005,2006,2007;
Multiple champion of Switzerland.

Christophe Sauser:

Vice world champion 2005,2006;
World champion of marathon VTT 2007.

Florian Vogel :

3rd of the Championship of the world 2007;
Championd of the world of the TEAM relay 2006,2007.

See too

References

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