Derailleur gears a detent or ratchet mechanism which stops the gear lever, and hence the cable and the derailleur, after moving a specific distance 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 either. Many modern, high-end mountain bikes have begun using entirely one chain ring drivetrains, with the industry constantly pushing the number of rear cogs up and up, as shown by SRAM's Eagle groupsets (1 by 12) and Rotor's recent 1
What Is to Be Done? (Tolstoy) the same Biblical reference (Luke 3:10–14). What Is to Be Done? (Tolstoy) What Is To Be Done? (sometimes translated as What Then Must We Do?) is a non-fiction work by Leo Tolstoy, in which Tolstoy describes the social conditions of Russia in his day. Tolstoy completed the book in 1886, and the first English language publication came in 1887 as What To Do?. A revised translation with the current title was published in 1899. The English title was also used for two better-known works by Nikolai Chernyshevsky and Vladimir Lenin; Tolstoy's Russian title is similar but not identical to Chernyshevsky's