40 bhp, 425 lbs and 100 mph:


The Square Four was designed by Edward Turner and first produced in 1931. Initial bikes (4F) were 500cc and then 600cc. In 1937 the 997cc model 4G was introduced and in 1949, with the 4G Mark  1 model, alloy heads replaced the previous cast iron heads. The final version was the 4G Mark 2 which had four separate exhaust pipe outlets from the head - thus improving cooling to the rear cylinders. In total 15,639 Square Fours were built of which 3,828 were the 4G Mark 2. It was complex and expensive to produce and needs good technical skills to keep on the road.

The Square 4 is very smooth to ride, has a unique and distinctive sound and has loads of torque - pulling in 4th gear from under 20 mph. The front brake, however, leaves a lot to be desired.

This bike has matching numbers and has had a nut and bolt restoration undertaken by Reeds Classics. It is original apart from 12 volt electrics.

1957 Ariel Square Four - 4G Mark 2 [997cc Square-4]