For a number of cyclists, chain rings are simply the round metal objects attached midway along the right side of the bicycle. In truth, chain rings contribute to propelling the bicycle forward, by helping rotate the bicycle's chain. Chain rings also serve a crucial role in allowing the cyclist to choose among various gears. Chain rings come in various sizes to suite the individual needs of the cyclist.
Each chain ring is lined with individual "teeth" over which the chain rides. The size of a chain ring helps determine the "feel" of a particular gear choice. A larger chain ring, or higher gear, requires greater effort to turn than a smaller chain ring. However, a larger chain ring causes the bicycle to travel further per rotation of the crank than a smaller chain ring. For this reason, cyclists sometimes choose a chain ring setup that is the most ideal for a particular terrain.
A compact bicycle crank has two chain rings. A typical compact crank will consist of a 50 by 34 combination. The two figures refer to the number of teeth on the large and small chain ring, respectively. The relatively small size of the chain rings makes the compact ideal for use in mountainous terrain. Turning the smaller gears allows the cyclist to maintain a higher cadence while battling gravity.
Like the compact, the standard bicycle crank consists of two chain rings. The rings, however, generally measure 53 by 39. The 53-tooth chain ring makes it ideal for flat terrain and high-speed efforts. The 39-tooth gear may be used for climbing hills and fighting head winds. A trained cyclist may also be able to use the combination in mountainous terrain. The standard setup is common among professional and competitive road cyclists.
As its name implies, a triple crank set consists of three chain rings. Common chain ring sizes for triple crank sets include 52 by 42 by 32 and 53 by 39 by 30. The wide range of gearing options provided by the triple chain ring setup makes it ideal for leisure cyclists or for anyone riding in a variety of conditions. The large chain ring provides effective gearing to enjoy flat roads and tail winds, while the smaller chain rings help reduce the effort needed to conquer various levels of climbs.
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