ARIEL SQUARE FOUR BACKGROUND The Square Four engine was originally designed in 1928 by Edward Turner, the man who later came up with the vertical twin for Triumph. In original form, it started out as ...

Ariel actually made a prototype of a Mark 3 in 1954, complete with plush Earles suspension, but the bike never made it into production and the Square 4 – along with all other four-stroke Ariels ...

1952 Ariel Square Four 1952 ARIEL SQUARE FOUR BACKGROUND The original Ariel Square Four was created by legendary engine designer, Edward Turner in 1930. In its original form, it displaced 500cc and ...