Lever resistance (or load). It is common to call the input force "the effort" and the output force "the load" or "the resistance." This allows the identification of three classes of levers by the relative locations of the fulcrum, the resistance and the effort: These cases are described by the mnemonic "fre 123" where the fulcrum is in the middle for the 1st class lever, the "r"esistance is in the middle for the 2nd class lever, and the effort is in the middle for the 3rd class lever. The lever is a movable bar that pivots on a fulcrum attached to
Shimano Total Integration lever applying tension to the gear cable, the smaller one incrementally releasing it. The Rapidfire mechanism was subsequently adapted to be used in STI levers. In 1990, Shimano introduced their STI shifting levers for road bicycles, which completely integrated the brake lever and shifter. It also redesigned the brake "hoods" where riders commonly rest their hands. This new design worked like a normal brake lever in the longtitudinal plane, but also allowed the rider to shift to a larger cog by pushing the lever so that it pivots laterally. Behind the brake lever, there is a smaller lever that shifts