The AA used over 2000 of the M20, and later M21 models
BSA motorcycle combinations were the mainstay of the AA's breakdown fleet in the 1950s and the early 1960s. The AA used over 2000 of the M20, and later M21 models, and was the last purchaser of the M21 when production ended in 1961.
The M21 combination was an unsophisticated but robust machine, powered by a 600cc single-cylinder sidevalve engine producing a modest 15 bhp, which propelled it to barely 50mph.
The AA ordered a different specification from standard, which included a stronger front brake, a 12v alternator instead of a dynamo to power the two-way radio, and higher, 'western-style' handlebars.
600cc single-cylinder sidevalve engine
Various types of sidecar, leg-guards and fairing were produced.
During the 1960s the need to carry more equipment (not to mention the desire of AA patrols to keep out of the weather) meant that the motorcycle combination was gradually replaced by the Mini van. It was the end of an era – the traditional AA patrol salute was abandoned in 1961, and the last BSA was retired in 1968.
There are 4 BSA M21s on the AA's heritage fleet, looked after by various AA breakdown patrols around the country.
There is also a BSA M20 on display at the Meadowhall shopping centre near Sheffield.
(10 June 2013)