BIKES YOU’VE NEVER SEEN BEFORE: 1955 ARIEL 500 HS MOTOCROSS

The Ariel 500 HS Cross was both a last gasp for Ariel’s 500cc four-stroke engine, but also the end of the era of the Big British Single.

To many motorcycle fans the Ariel brand is best known for its innovative 1931 Ariel Square Four 500. The Ariel Square Four, with a 500cc engine designed by Edward Turner, first appeared for the 1931 season. Around this time the company went into receivership and when a new company was formed, the Square Four displacement was increased to 600cc.

During the Second World War Ariel made bikes for the British Army. After the war, Ariel was bought by BSA and they produced the Ariel 500 HS Cross, which was a true enthusiast design. Today, the Ariel named was licensed to be used on a lightweight, two-seat, sport cars called the Ariel Atom.

The Ariel name came from the Shakespeare play “The Tempest.” In the play, Ariel was a spirit, loosely based upon the Roman messenger, Mercury. The first motorized Ariel was a tricycle in 1898 and the first Ariel motorcycle followed in 1901. It used a 211cc Minerva engine. Until 1926 Ariel motorcycles were equipped a variety of other brand’s engines, including JAP, MAG, Minerva and AKD V-twins.

In 1925 Ariel employed Val Page as their new designer. Page was fresh from JAP and by 1926 he had designed Ariel a totally new four-stroke engine. It would come to be known as the Red Hunter engine and in various configuration had an almost 30-year lifespan.

In the 1950s, as scrambles and trials became more important, Ariel worked on building its HS line. The 1954 Ariel 500 HS single gained a swingarm frame, new alloy cylinder head, 34 horsepower and and a straight-through exhaust pipe. The single-cylinder, air-cooled engine displaced 497cc, the bore and stroke was 81.8mm X 95mm and the compression ratio was 7.5:1.

The street-legal Ariel 500 HS was not a light motorcycles—pushing 365 pounds, but for the Scrambles/Cross model they shaved weight by eliminating the lights and generator, and using alloy fenders.

Most of all the Ariel 500HS Cross delivered great performance and its look were embraced by off-road racers in England and the Continent—thanks in no small part to the attractive bright red gas tank. It was the bike of choice for scrambles or trials (with both the 350 and 500 HT models). The 500 HS shared the same frame as the road going model, but the motocross frame used high-tech Reynolds tubing.

The 50cc Ariel 3 had nothing to do with the proud Ariel brand. It was built by BSA as they approached the brink of insolvency.

Sadly, the last model to bear the great Ariel name was the 1970 Ariel 3, a tricycle moped produced by the BSA, and also sold by BSA (who owned the Ariel name). It had a 50cc Dutch-built, Anker, two-stroke engine and a front wheel that leaned into corners. Ariel owners were least likely to buy a 50cc moped and the Ariel 3 was a flop—and an everlasting blight on the good name of Ariel.

The Ariel name lives on with the minimalist Ariel Atom sports car.