Modern Derailleur Types
The major innovations since then have been the switch from friction to indexed shifting and the gradual increase in the number of gears. With friction shifting, the rider first moves the lever enough for the chain to jump to the next sprocket, and then adjusts the lever a slight amount to center the chain on that sprocket. An indexed shifter has a detent or ratchet mechanism which stops the gear lever, and hence the cable and the derailleur, after moving a specific distances with each press or pull. Indexed shifters require re-calibration when cables stretch and parts get damaged or swapped. On racing bicycles, 10-gear rear cassettes appeared in 2000, and 11-gear cassettes appeared in 2009. Most current mountain bicycles have three front chainrings; road bicycles may have two or three.
Read more about this topic: Derailleur Gears
Famous quotes containing the words modern and/or types:
“Miss Nancy Ellicott smoked
And danced all the modern dances;
And her aunts were not quite sure how they felt about it,
But they knew that it was modern.”
—T.S. (Thomas Stearns)
“The bourgeoisie loves so-called “positive” types and novels with happy endings since they lull one into thinking that it is fine to simultaneously acquire capital and maintain one’s innocence, to be a beast and still be happy.”
—Anton Pavlovich Chekhov (1860–1904)