Automatix

Brand: SRAM

Two-speed internal gear hub with AUTOMATIC shifting, a technical curiosity from SRAM born of Sachs-Torpedo know-how (SRAM took over Sachs' bicycle division in 1997). It has no shifter and no cable: the change from the direct ratio (1.00) to the overdrive ratio (1.36, i.e. a 36% step) is made by centrifugal force. Internal weights, held by a calibrated spring, are thrown outwards as the wheel speeds up; beyond a threshold (around 135 rpm, i.e. ~16 km/h with a 26-inch wheel in the 36-hole version) they engage the splines of the shell and bring in second gear. The return to first happens automatically as speed drops. Offered with coaster brake, disc brake or Rollerbrake, steel or aluminium shell (940 to 1384 g). Sold until 2017.