Alas, the world was changing, and with it the motorcycle market. The Ariel Square 4 designed decades before, was keyed to another age, one where acceleration and all-out top speed weren’t as important ...

The original Square Four was conceived by legendary motorcycle designer, Edward Turner, who later created the game-changing Triumph parallel twin. His original design for the Square Four was an OHC ...

VINTAGE - 1905 - 1944 Due to the rarity of these and other years and models of Ariel, pricing data is still being collected. These are approximate pricing guidelines. Make sure you're protected!

Pioneered by Ariel and used by a few other brands, it was wonderfully balanced and sounded great. How come it's not in use today? Did you know that a square four engine used to be a thing? In fact, ...