The kei truck class specifies a maximum size and displacement, which has steadily increased since legislation first enabled the type in 1949. They evolved from earlier three-wheeled trucks based on motorcycles with a small load-carrying area, called
san-rin (三輪), which were popular in Japan before World War II. Since 1998, the law admits a maximum length of , a maximum width of and a maximum height of with a maximum displacement of 660 cc. They weigh about , and when ungoverned, can reach up to . Due to the limits established with regard to vehicle length, most, if not all, current trucks in this classification are built with the "
cab over" approach to maximize load-carrying abilities; the
Suzuki Mighty Boy is one of the rare historical exceptions. Despite the size and engine displacement, most kei trucks have a bed load capacity of , and the bed dimensions are comparable to crew cab versions of far larger vehicles such as the
Ford F-150. Kei pickups generally have pickup beds with fold-down sides; dump and scissor-lift beds are also available, as are van bodies. For export markets, kei trucks are usually fitted with bigger engines to allow them even more carrying capabilities. An Indonesian version of the originally 543-cc Suzuki Carry was built with a 1.6-litre unit – nearly three times larger. They are built with a strong, full, box-frame design with fully enclosed
cabs,
seat belts,
windshield wipers,
AM radios, heaters, lights and signals, and catalytic converters, and are claimed to have a fuel efficiency of . Typical manufacturers and model names include:
Daihatsu Hijet,
Subaru Sambar,
Suzuki Carry,
Mazda / Autozam Scrum,
Mitsubishi Minicab. Honda has ended production and sales of kei trucks with the end of production of
Honda Acty in 2021. The first kei truck to go on sale was the
Kurogane Baby, manufactured from 1959 until 1962. Many of these have been produced under license abroad, such as the
Piaggio Porter. In South Korea, Daewoo and
Asia (Kia) produced rebadged Suzuki Carry/
Every, and Daihatsu Hijet vans as Daewoo Labo/Damas, and the Asia/Kia Towner. == Uses ==