ABC Classic Bikes
In 1919, many motorcycle manufacturers
who had been involved in war work found themselves
facing the prospect of cutting back their activities
unless they could diversify into other types of production.
One such manufacturer was Sopwith of Kingston-on-Thames,
Surrey, an aircraft company that faced a sudden downturn
in demand. Proprietor Tommy Sopwith believed that
motorcycle production could be the answer and turned
to the designer Granville Bradshaw for help.
The solution that Bradshaw offered was the astonishingly
bold ABC flat-twin - even more extraordinary because
the design was completed in a mere 11 days! He had
bet Sopwith that a prototype could be produced in
three weeks - and backed up his bold claim with a
deal whereby he stakes £100 per day over that
time, while Sopwith would pay a similar sum for every
day less. As a result, Bradshaw netted £1000
on the deal.
A bike built so quickly might have been expected
to be crude, or at least a copy of an existing design,
but the ABC was neither. Its horizintally-opposed
twin-cylinder engine employed overhead-valves and
it had an integral four-speed gearbox.
When it was launched, the ABC captured the imagination
of the reviewers. Lightweight and quiet, the bike
had a brisk performance, as well as being comfortable
and stable. Orders began to flood in and the French
company Gnome at Rhome were signed up to produce the
design under licence.
Then the troubles began. Initially priced at £70,
the ABC proved too expensive to manufacture and the
design had to be modified to sort out some mechanical
problems. Sales should have begun early in 1919 but
when the first bike appeared in May 1919, the price
had risen to an astronomical £160 and even at
this price the manufacturers were hardly covering
Only some 2000 were made. Although the ABC's proved
capable of winning two speed records in the year they
were launched, it soon transpired that the valve gear
was weak and prone to breakage. While accessory makers
offered cures for its mechanical problems, the factory
itself quietly let the unprofitable ABC fade away.
The last one made by Sopwith was built in 1923, although
Gnome et Rhome made a few up until 1925. After that
it was left to others - especially the flat-twin BMWs
- to demonstrate what the concept might have offered.
- Years in production - 1919-25
- Engine - horizontally opposed twin-cylinder overhead-valve
- Bore and Stroke - 68.6 x 54mm
- Capacity - 398cc
- Carburettor - Claudel-Hobson
- Gearbox - four-speed with H-gate
- Top Speed - 70mph