Track bicycle

A wheel ( also web machine ) is a road bike for track racing. It has no brakes and a circuit or freewheel and has a different frame geometry to as road racing bikes.

Track bikes are basically constructed according to the same design principles, which are also in racing bikes for road bicycle racing application, but some of them are more prominent: The focus is on the driver's maneuverability on the bike - that is, the wheel is on as directly as possible the driver's steering maneuvers respond.

Basic principles

The following basic principles thus arise for railway wheels:

• Wheelbase: while already have road racing bikes compared to a usual use wheels shortened wheelbase of 95-100 cm, this usually is railway wheels under 95 cm;
• Head tube angle: while sought for road bikes head tube angle 72-74 degrees, have train wheels on steeper head tubes with angles that are sometimes far more than 74 degrees. The head tube angle affects the tracking of a bicycle: the steeper the angle, the lower the overrun. Since the lag dampens independent of the driver fixes precession steering angles, a wheel carrier with high overrun, but directionally stable. Since this property is not desired in track cycling, the lag is kept low: the wheel is thus more maneuverable, but also in his straight nervous by the steeper head tube.

Specific design principles and technical characteristics of railway wheels

While the above-mentioned properties, the wheel differ only in degree from road racing, track bikes have more specifics on:

• Bottom Bracket: During road racing wheels relative to use wheels have a markedly Lowered bottom bracket, the bottom bracket is in turn placed 3-5 cm higher at train wheels, to exclude a touchdown with the cranks in the curves or performing evasive maneuvers.
• Lack of derailleur and brakes, rigid response: To reduce the risk of falls in the high speed and the cramped conditions on the track, track bikes have no freewheel nor brakes, the so-called rigid gear is required, which is why they also have no circuit. The rigid transition causes must be mitgetreten while driving permanently. In order not to drive on and another driver deviates from you - especially to the right, because the speed is then immediately reduced by the train cant. In an emergency, the speed can be against the rotating pedal, also reduced by " Abkontern ", ie counter- hold with muscle strength. As the road traffic licensing regulations, inter alia, requires at least two brakes, track bikes are not approved for use on public roads.
• Stiffness and weight: train wheels must especially the special forces ( esp. acceleration, direction changes and centrifugal forces in curves ) are good enough. For this reason, there is no so much of the weight as the stability.
• Tyres: The tires are mainly 27-inch tube tires. They can be more inflated than the known normal bicycles clincher and thus hold heavier loads Stand In track races are prescribed Tubular by the UCI for security reasons.
• Axle width: Unlike the standard axle width of 130 mm or 135 mm in the normal road bike when mountain railway wheels due to the lack sprocket assembly reduced to 120 mm wide at the rear wheel.

The driver's position

The position of the rider is leaning more on the wheel in the rule. It is run in competition almost exclusively in the " the drops ". Because of the high pressure in the curves and to allow for permanent the drops a more comfortable position of the hands on the handlebars, many drivers turn the Barends more down, so that compared to the usual 15 to 25 degrees inclination often inclinations are to be found up to 45 degrees. It is also popular, the saddle not level, but to assemble with a clear tendency of the tip down.

Because of the higher cadence and the shorter cranks used on the web, a lower of 0.5 to 2 cm seat position is adjusted.

Speed ​​, translation, cadence and crank length

Basically, there are three parameters speed, translation and cadence in a fixed ratio: The greater the speed, the greater at constant translation, the cadence, the smaller the ratio, the greater turn at constant speed cadence.

On the train both is to be found: higher speeds with consistently smaller translations. Therefore, the crossover frequencies are in track racing with 110 to 170/min consistently higher than on the road ( 85 - on the mountain even to under 50 - to 120 rpm ). Higher ratios that would allow a lower cadence does not correspond to the power structure of the track events and inhibit the driver in its mobility on special maneuvers. Standard translations are in professional as in the amateur 52/16 (Bruno Risi), 52/15 ( Joan Llaneras ) and 49/15, notwithstanding this particular translations are in individual disciplines (ex. 64/14 in the pacemaker race, 50/ 14 in the Sprint ).

In assessing the effectiveness and appropriateness of a translation in addition to the nominal translation and the crank length has to be considered as a numerical ratio of chainring to sprocket assembly. They determined not only by the translation and the speed with the speed of contraction of the muscles. To allow a crank length of 180 mm with a translation of 53/17 example, the same rate of contraction and the same average power use as a crank length of 170 mm with a translation of 53 / 18th

Whether these two " equal " Translations the one or the other is selected, depends on various conditions. These include:

• Body size and physique of the athletes
• Type of stress: endurance exercise or Sprint.

While endurance performance on the road or train longer cranks are preferred, use sprinters extremely short cranks because they, in the course of the whole pedaling cycle will move possible in virtue of the optimal range is. ( For example, chose Eddy Merckx during his hour record with 52/14, although a relatively high ratio, but also used with 175 mm cranks longer than on the web at its body size are common. )

As in road racing are for the students, youth and junior classes translation restrictions.

Regulations

The UCI has exactly defined, must like train wheels look like. The form of time trial bikes in track cycling is compulsory for record attempts such as the hour record and largely corresponds to the technical status of the bicycle, with the Eddy Merckx in 1972 set the hour record of 49.432 kilometers. Disc- wheels are standard and approved, but not exclusively used.

New Trends

Mid-1980s, began in New York bike messengers to use Railway wheels for their work on the streets of Manhattan. This trend planted continued in European cities. Special shops, usually in combination with bicycle courier services, offer converted road bikes with fixed gear, fixie called (of English. Fixed gear ), for use on the street. For this, however, brakes are not always mounted, which will void the approval for use on public roads. Some drivers, it is sufficient to reduce the rate by muscle power over the rear wheel. There are also so-called " track bikes " available. It is at first only to racing bikes without gears and brakes. Meanwhile, there are special " Straßenfixierahmen " for a variety of purposes, such as Kurierrad or Trickrad. These bikes have, however, apart from their outward appearance has nothing to do with track bikes, they have to drive on the track inappropriate and prohibited.