bike - Racing bicycle
Photograph by Thirteen Of Clubson Flickr.
SRAM: Red (10s), Force (10s), Rival (10s). In the mid 1990s Mavic, known for their wheelsets, introduced an electronic shifting system which was pioneered in the Tour de France by American bike Road bicycle Greg LeMond and later on by Briton Chris Boardman, who liked the fact that the system allowed him to shift from his aerobars and his brake levers. A racing bicycle, commonly known as a road bike, is a bicycle designed for road cycling according to the rules of the Union Cycliste Internationale (UCI).
Dual control addressed the problem of having to reposition a hand to change gears. Campagnolo and SRAM have introduced carbon fiber for their high-end shifters and brake levers, cranks, and parts of their derailleurs.
Recently, Shimano have announced that their 2009 Dura-Ace groupset will include both manual and electronic shifting options. Carbon fiber has also become more popular for components. Other than this, the general design of a racing bicycle has changed little since the development of derailleurs. The road groupset levels that these companies offer are as follows, from highest to lowest level.
Recumbents were excluded from the UCI definition of a bicycle on 1 April 1934. Time trial bicycles are a subset of racing bicycles that are designed for time trial events. They are inflated to a high pressure, typically around 8 bar (820kPa/120psi); track racing tires can be inflated up to circa 14 bar.
The advantages of carbon fiber are low weight as well as increased vibration dampening leading to a more comfortable ride. For recreational road cycling, the racing-style bicycles with drop handlebars used to be the norm in the 80s, along with the touring bicycle, (a drop-handlebar bike with a slightly longer wheelbase to provide suspension). The Mountain bike geometry with its straight handle bar and comfortable sitting position (resembling the city bike), have moved into the high-performance spaces, and high production volumes have brought down costs significantly. Owing to the lower air resistance and better body stance for pushing, road bicycles tend to be more efficient for use on smooth roads.
At the same time, a product launched in 2008 to dynamically alter the rotating inertia of bicycle wheels claims to have outperformed the standard, equivalent wheel by 5.6sec/mile. For aerodynamics and rotating weight, it is generally better to reduce the number of spokes in the wheel. Until recently, most racing bikes used tubular/single/sew-up tires which have no beads: they are sewn around the tube and glued to the rim.
Some manufacturers create tubular-clincher tires, where the tires are sewn around the tubes and have a bead, but there is some debate as to the effectiveness of a tubular-clincher tire. To this effect racing bicycles may sacrifice comfort for speed.
STI was followed by the competing Campagnolo/Sachs Ergolever. The system did not catch on due to technological hurdles, but it has been rumored that Campagnolo has been developing an electronic groupset and has been field tested as recently as the 2005 Giro d Italia. In early March 2006, some pro riders were seen riding with Shimano electronic shifting groupsets; further testing in the pro-ranks continued during the next 2 years.
The front and back wheels are close together so the bicycle has quick handling. STI is characterized by its combined brake and shift levers, or brifters .
Advances in tire technology, however, have seen the far more practical (due to greater ease of changeability) clincher (beaded) tire close the gap. However, a particular benefit of the tubular-clincher design is that the risk of pinch flats is very low (like the tubular tire), yet it allows the use of the more popular clincher wheel. Race bike components (excluding frame, fork, wheelset, bars, stem, pedals, saddle and seatpost) are collectively referred to as the groupset.
In 2006 SRAM introduced their Force and Rival racing groupsets . The two major groupset manufacturers of complete groupsets for racing bicycles are Shimano and Campagnolo.
These designs, called road bikes or colloquially, roadies or racing bikes , have become less popular in recent years. For hill climbs, however, energy losses due to the higher weight of most aerodynamic rims are greater than the aerodynamic drag reduction that they offer, so a traditional lighter box-sectioned rim is often used. Wheel moment of inertia is a controversial subject.
These tires provide an advantage in weight (lacking the relatively heavy wire bead), rolling resistance, grip and pinch flat protection, but their greatest advantage lies in the ability to use a very lightweight simple box-section rim, rather than the U-shaped clincher rim. The quality of the groupset determines how refined the bike feels, how much maintenance it requires, and contributes to the performance of the bike.
Proponents believe that it has all the advantages of a tubular tire made to fit a clincher rim, but critics argue that the design includes disadvantages inherent to both systems---the rim weight is still high, the tire is more expensive than a standard clincher tire, and repairing a puncture on a tubular clincher is as inconvenient as it is with a standard tubular tire. Previously, the shifters were mounted on the stem, handlebar ends or the down tube of the frame.
Other racing bicycles, especially those used in time trialling prioritize aerodynamics over comfort. Bicycles for racing on velodromes are track bicycles; bicycles for racing offroad are mountain bicycles, cyclo-cross bicycles or cycle speedway bicycles; bicycles that race according to the rules of the International Human Powered Vehicle Association include faired recumbent bicycles which, on flat ground, are the fastest bicycles in the world. Campagnolo: Super Record (11s), Record (11s), Chorus (11s), Centaur (10s), Veloce (10s), Mirage (10s), Xenon (10s).
Shimano: Dura-Ace (10s), Ultegra SL (10s), Ultegra (10s), 105 (10s), Tiagra (9s), SORA (9s), 2300 (8s). Using a molded carbon fiber rim reduces weight compared to a metal rim.
Therefore, wheel moment of inertia effects are neither noticeable nor important. (See rules 1.3.020 to 1.3.023) Triathlon bicycles are governed by International Triathlon Union (ITU) rules, which allow more recent technological developments than do the UCI rules. The wheels greatly affect the performance of a racing bike.
The rim of the wheel can be shaped for greater aerodynamic efficiency making a triangular cross-section to form a teardrop with the tire. Riders who race often choose to own at least two pairs of wheels: a heavier, more durable, and cheaper wheelset for training, and a lighter, more aerodynamic wheelset for racing. To reduce both air resistance and rolling resistance on the road, tires are lightweight, narrow, and have a thin, smooth tread.
The companies have different design philosophies, and some cyclists have great brand loyalty for one or the other. In the early 1990s, Shimano introduced dual-control with a system called Shimano Total Integration (STI). The number in the brackets indicates the number of cogs on the freewheel.
The drop handlebars are positioned lower than the saddle in order to put the rider in a more aerodynamic posture. They have wider, treaded tires and cantilever brakes instead of caliper brakes but are still less efficient than racing bikes at higher speeds. The UCI rules currently specify that a racing bicycle have the following characteristics, : Note that the regulations regarding the dimensions of the bike are allowed exception, given that the rider can demonstrate a morphological need for the exception based on limb size or other factors. UCI ProTour • UCI Women s Road World Cup World Championships • Olympic Games • National championships • UCI Continental Circuits: Africa Tour • America Tour • Asia Tour • Europe Tour • Oceania Tour Grand Tour • Race stage • Classics • Criterium • Individual time trial • Team time trial Racing bicycle .
In this article: wheel theory, the author does some calculations on wheel effects. Cyclo-cross bicycles, which are used for racing on off-road circuits, are closer to racing bikes than to mountain bikes.
Carbon fiber stems, handlebars, shoe soles, forks and seatposts are also more commonplace, including integrated stem/handlebar combinations. Using exotic materials, race-grade wheelsets are very expensive.
Moment of inertia changes result in a decrease in watts of between .004 and .022%, while lower mass provided between .2 and .46%, and better aerodynamics provided between .6 and 1.8% decrease in wattage. The UCI rules were altered in 1934 to exclude recumbent bicycles. The most important characteristics about a racing bicycle are its weight and stiffness which determine the efficiency at which the power from a rider s pedal strokes can be transferred via its drive train and to its wheels.
The UCI rules for these bikes are slightly less prescriptive than those for massed start road races . For high-end wheelsets, the spokes can be shaped to have a bladed cross-section, further reducing wind resistance. The most common material for a wheel rim is aluminum alloy.
