January 2015
ARIEL MOTORCYCLES
A Bit of History
Ariel Motorcycles was a British motorcycle manufacturer based in Bournbrook,Birmingham. It was one of the leading innovators in British motorcycling, and was part of the Ariel marque. The company was sold to BSA in 1951 but the Ariel brand survived until 1967. Influential Ariel designers included Edward Turner and Val Page. The last motorcycle-type vehicle to carry the Ariel name was a short-lived 3-wheel tilting moped launched in 1970.
Ariel had made bicycles before making motorcycles, and had also made automobiles. Car production, which began in 1902, moved to Coventry in 1911, but ceased in 1925.
The 'Ariel' name was reused in 1999 for the formation of Ariel Ltd, a sports car producer.
1950 Ariel Square Four 4G Mk1
Ariel's four-cylinder Square has a reputation of being a gentleman's motorcycle. Some of them can be a little more lively. Meet the classic bike which bit back...
The Square was an ideal machine for its regular duties, commuting to work and providing family transport for husband, wife and the four kids.
When unfettered by domestic bliss, the 1950 4G Mk1 Square could exceed 90mph, and its gentle power delivery provided ideal propulsion for the fully-laden outfit, giving smooth, seamless acceleration from low revs. 35bhp went an awful long way in those days! It helped that the 4G produced its peak power at just 5500rpm with a broad spread of tractable torque, so the pilot didn't need to continually cog-swap between the four ratios in the Burman box. 'Effortless' was a word often associated with riding the Square Four…
The Square Four model was initially a twinkle in Edward Turner's eye back in the 1920s when he worked at BSA. Yes, the 1920s - and even then four-cylinder motorcycles weren't new. The first four-pot two-wheeler we know of was the 1901 Holden. Anyway, after moving to Ariel and enlisting the aid of engineer Bert Hopwood, Turner's idea was made into metal in 1931 in the shape of the first, 4F 500cc Square Four. Turner had really intended his overhead cam four-cylinder motorcycle to be a fast sportster but it wasn't to be: instead the Square became a heavy tourer, famed for its long legs and relaxed ride rather than outright performance. When Turner moved on from Ariel, Val Page continued the Square's developments and it grew to 600cc in 1936 and then an OHV 998cc.
From 1939 the 998cc Square Four could be ordered with Anstey link rear suspension and this version of the model was the one offered immediately after the war, now with telescopic front forks instead of girders but keeping its all-iron engine which had a tendency to overheat. It was a massive machine for the time, weighing in at around 215kg, although the low saddle height of just 28-inches and good weight distribution made all that mass manageable.
A major redesign was needed for the Square to be suitable for the 1950s so for 1949 the new model 4G Mk1 was launched with an all-alloy engine running at just 6:1 compression. Although the bottom end was much the same as before the war, the cylinder head, valve gear, crankcases, rocker box and such were all overhauled. The magneto was replaced by coil ignition with dynamo lighting. The modifications helped the Square's cooling and reduced its weight to under 200kg, as well as giving acceleration something of a boost. Braking was provided by single leading shoe, seven-inch drum brakes at each end, and an eight-inch brake arrived in 1951. Fuel consumption wasn't spectacularly good for the time, at between 40 and 50mpg.
In solo trim, test riders found the Mk1's 'combination of zestful performance and roly-poly handling diverting and, on the whole, congenial.' Motor Cycling were impressed and reported 'acceleration which gives 0 to 92mph in under half a minute!' They also reckoned that 'the new Squariel combines the docility of a sidevalve with the out-and-out performance that can be equaled by very few vehicles.' Those were the days, when speed trials were measured in half-minutes…
Another update in 1953 created the Mk2 4G which featured the model's fabulous four-pipe exhaust system. The Square went out of production in 1959 and all types are extremely sought after these days. As Jeff Clew said; 'it is very pleasing to know that Britain had a very practical four cylinder model on the road so long ago, with its cylinders arranged in a form that is still quite unique today.'
