redlined. The AMT can be switched to a clutchless manual mode wherein one can upshift or downshift using a console-mounted shift selector or paddle shifters. It has a lower cost than conventional automatic transmissions. These transmissions are not to be confused with "manumatic" automatic transmissions, which are marketed under trade names such as Tiptronic, Steptronic, Sportmatic, and Geartronic. While these systems seem superficially similar, they are closer in design to automatic transmissions than manual transmissions. Sequential manual transmissions Several semi-automatic transmissions used by motorcycles and racing cars are actually mechanically based on sequential manual transmissions. Semi-automatic motorcycle transmissions generally omit the clutch lever, but retain the conventional heel-and-toe foot shift lever. Semi-automatic motorcycle transmissions are based on conventional sequential manual transmissions and typically use a centrifugal clutch. At idle speed, the engine is disconnected from the gearbox input shaft, allowing both it and the bike to freewheel—unlike with torque converter automatics, there is no idle creep with a properly adjusted centrifugal clutch. As the engine speed rises, counterweights within the clutch assembly gradually pivot further outwards until they start to make contact with the inside of the outer housing and transmit an increasing amount of engine power and torque. The effective "bite point" or "biting point" is found automatically by equilibrium, where the power is transmitted through the (still-slipping) clutch is equal to what the engine can provide. This allows relatively fast full-throttle takeoffs (with the clutch adjusted so the engine is at peak torque) without the engine slowing or being bogged down, as well as more relaxed starts and low-speed maneuvers at lower throttle and RPMs. Usage in passenger cars 1900s—1920s In 1901, Amédée Bollée developed a method of shifting gears that did not require the use of a clutch and was activated by a ring mounted within the steering wheel. One car using this system was the 1912 Bollée Type F Torpedo. 1930s—1940s Prior to the arrival of the first mass-produced hydraulic automatic transmission (the General Motors Hydra-Matic) in 1940, several American manufacturers offered various devices to reduce the amount of clutch or shifting input required. These devices were intended to reduce the difficulty of operating the unsynchronised manual transmissions, or "crash gearboxes", that were commonly used, especially in stop-start driving. An early step towards automated transmissions was the 1933–1935 REO Self-Shifter, which automatically shifted between two forward gears in the "forward" mode (or between two shorter gear