1934 Ariel Square Four
Making it’s first appearance at a London show in 1930, the Ariel Square Four was something of a sensation and it remained in production for over a quarter-century.
The initial offering, the 4F/5, was a 498cc “sports” model. The following year saw a new model, the 4F/6, with the engine boosted to 601cc. In 1936 the Square Four’s power plant became a heavier 995cc and the model was known as the 4G.
The power plant was originally designed in 1929 by the newly hired Edward Turner, who had taken the design idea to other manufacturers before it was picked up (along with Turner) by Ariel. At the time, the Square Four was a refreshing alternative to the established v-twins and inline fours.
Ariel’s parent company went bankrupt in 1932 and Jack Sangster bought the rights to the Ariel name, along with much of the tooling at reduced cost.
Under Sangster’s new company named Ariel Motors (J.S.) Ltd., Ariel continued to produce the Square Four. After World War Two, Ariel voluntarily allowed itself to be absorbed by BSA.
Sometimes known as a “Squariel” the Square Four had two cylinders directly behind the front two in the same cylinder block, and as might be imagined, it was plagued with heat problems. Despite the heat problems, the motorcycle remained in production until 1958.