Single-speed bicycle

The term Eingangrad (English single-speed ) means a bicycle that has no gears. Also there is no freewheel available, one speaks of a rigid transition. Colloquially, the buzz word Fixie (from engl. "Fixed gear" ) is often used for this. In Fixies is also sometimes omitted brakes; is then slowed down by back pressure on the pedals.

History

The history of the bicycle starts with the Eingangrad without freewheel, the it, and neither was in the 1860s, as the drive was invented about pedals and chain, such as the gear shift. The gears in the rear hub with freewheel was invented in 1902 and was from 1924 a significant spread, so that the proportion of input wheels has since declined significantly. Nevertheless, there are still bikes without gears, usually combined with a coaster brake. This design around the world remained prevalent until recent decades, affordable only with broad advent switching hubs have been displaced this. Input wheels with coaster today are almost exclusively found in the inferior area, an exception are Dutch bikes and children's bikes.

Reasons for waiving a gear shift

Nowadays, there are three main reasons for not using a gear shift on the bike:

• Cost: bicycles without gears are in many poorer countries continues to be the rule, since such bikes are also much cheaper to buy. Moreover, the absence of a circuit facilitates the construction of a bicycle from old bicycle parts. Even with factory bikes is sometimes omitted for reasons of cost (acquisition and maintenance) on a circuit.

• Special bikes: Input wheels without freewheel are the Radball, artistic cycling and BMX usual because it also moved backwards and the bike on the pedals is held in position. For rail wheels, a rigid gear for safety is required. Since these special bikes are not moving on public roads, bypasses a brake. For details, is explained in the main article rigid gear.

• Fashion and bicycle culture in Europe, Japan and North America, the absence of a gear change for used bikes on the road is a fad, especially among bicycle couriers. In these circles is sometimes dispensed with brakes.

Benefits

• The bike is lighter.
• The rigid steering allows the different cycling experience.
• The cleaning and maintenance of components of the gear shift is eliminated.
• Many input cyclists take pleasure in an optically " clutter " bike.

Disadvantages

• The range of application is limited due to the lack of transitions.
• The chain elongation must be compensated on a regular basis, unless you have a chain tensioner is used.
• In industrialized countries, Fixies are often expensive bespoke systems, as they are not available as an inexpensive mass-produced here.
• The absence of brakes to the rigid transition makes it difficult to stop considerably, is unsafe and also illegal in many countries.
• There are ground contact of the inside pedal during rigid transition possible, track frame also have lowered bottom bracket.
• With new chain adjustment if necessary to readjust the rear rim brake is required.
• Track frame are only suitable for road transport; the short wheelbase and low bottom bracket require high driving skills.

Technology

In the derailleur hub sprocket assembly is replaced by a single sprocket, the place of the deleted sprockets occupied by spacers.

Translation

The translation is determined by the number of teeth of the chainring and sprocket. It must be long enough to allow on level ground or downhill a reasonable speed, but at the same time short enough to allow the starting and driving on slopes.

In the mountain area is known as the standard 2:1 ratio. This means that the front chain wheel having twice as many teeth as the rear sprocket. To ride in the alpine area easier translation is gladly taken. If you drive mostly on the flat, selects a bigger gear. When racing the usual translation, depending on the application and force between 2.1:1 ( winter training road, eg 39/18 ) and about 3.3:1 (eg 52/16, a widely used standard in translation Six Days ).

For comparison, the driven road cycling race at flat route profile translations are, however, between 3.2:1 and almost 5:1. However, even requires, a translation of, eg, 53/11 in the final battle ( at speeds up to 70 km / h) a cadence of about 115/min, reflecting the importance of cadence -oriented training - for example, with the rigid gear - underscores.

Chain tension

Prerequisite for trouble-free driving is always a sufficient chain tension. The gradual chain elongation during operation requires regular re-tensioning. There are several methods:

• Special input frames have - like many older bikes and frames for IGH - often horizontal dropouts. This allows the rear wheel to move forward and backward to tension the chain. Under certain circumstances it also the position of the rear brake must be adjusted. These horizontal dropouts facilitate tensioning of the chain and a properly fitting mounting the rear wheel by laymen.

• Wherein dropouts an optional disc brake is shifted to the impeller, so that a correction of the position of the rear-wheel brake is not required.
• With an eccentric hub, the position of the axis of the rear wheel is movable. This is possible in any bicycle frame.
• With eccentric bearings, the position of the bottom bracket is adjustable so that about the chain is tensioned. The disadvantage of this construction is that to change the effective seat angle and the distance from the saddle to the pedal during the tensioning of the chain slightly. By integrating into the shell, this is the most unobtrusive device for tensioning the chain. Since the rear wheel always has the same position, there is no correction of the position of the rear wheel brake.
• On the chain tensioner the chain while running a small role, their position by spring force is variable. There are also designs with multiple roles.
• A so-called half-link chain can be cut in smaller increments than an ordinary chain, so that a correspondingly smaller adjustment between chainring and rear is required. This can greatly simplify the adjustment work, for instance because the adjustment of the brake pad position is not required.

Rigid transition

For the rigid drive up into the 1950s rear hubs were prepared which had a rigid transition and on the other hand, a 3-fold sprocket with freewheel on one side. The rear hubs used until the 1980s could be converted to rigid transition without much trouble, because the freewheel was integrated into the sprocket. The ring gear together with freewheel could therefore easily be replaced with a rigid pinion. With the advent of integrated into the hub freewheel this simple possibility no longer exists. The use of the rigid transition is only possible using appropriate hub, mostly railway hubs.

Legal situation in the absence of brakes

In the public road brakes are mandatory in most countries, often two independently functioning braking systems.

Germany - § 65 of the Road Traffic writes " two independent brakes " before. There's a court decision, according to which a rigid drive counts as a brake, because you can brake the rear wheel with the pedals. Accordingly, bicycles need with rigid transition only a "real" brake.

Austria - The Road Traffic Act ( Highway Code ) refers in § 66 Abs 2 with respect to nature of bikes on the bike Regulation ( FVO). This includes in § 1 para 1 lit 1 required two independently acting braking devices with a minimum delay.

Switzerland - Bicycles must be equipped with " two good brakes ", of which " one on the front and the other on the rear " acts (Art. 214 VTS).

France - To be allowed to participate in the road, it requires two brakes. This law is, however, rather little enforced, and the emergence of officially non-aviation -grade bicycles is relatively high.

Denmark - All bicycles must have a working brake on each wheel.

United States - The use of bicycles without brakes on public roads is illegal in many places, but the wording is often like " ... must be equipped with a brake that enables the person to slow down the bike on dry, clean pavement planierter and ... " and allows the argument of braking with the legs and the rear brake. In the retail sale of fixies with no brakes by the U.S. Consumer Product Safety Commision is prohibited.

An exception to this are track bikes ("... is a bike which made ​​for sale as racing bike with tubular tires, one gear and no freewheel, thought. ").

United Kingdom - The Pedal Cycles Construction and Use Regulations 1983 require bicycle " with a saddle height over 635 mm, two independent braking systems, one for the front and one to have for the rear wheel. " It is generally accepted that a front brake and the fixed rear brake meet this requirement.

Australia - In Australia bikes need at least a working brake.

New Zealand - The legislature writes for all bikes at least " ... a good rear brake ..." and for the bikes that were built after January 1, 1988 " ... a good front brake " before.