Non-synchronous transmission

Non-synchronous transmissions are found primarily in various types of industrial machinery; such as tractors and semi-tractors.

Most early automobiles were rear-engined, using a single-speed transmission and belt-drive to power the rear wheels.

In big rigs and semi-trucks, the driver may have to complete 24 or more gear changes when accelerating from a standstill to 70 mph (110 km/h).

[7] Non-synchronous transmissions are mostly used in semi-trucks, large industrial machines, older agricultural tractors (e. g. Massey Ferguson 135) and power take-offs.

[10] Sequential manual transmissions, which are commonly used in motorcycles, ATVs, and racecars, are a type of non-synchronous (unsynchronized) manual transmission, where gear ratios must be selected in succession (order), hence direct access to a specific gear ratio is not possible.