Whilst passing the Classic 50cc Racing Club this racer with an unusual frame construction
caught my eye. Built by Alan Leeson in 2010 with permission from Tony Dawson to see
whether it would produce a lighter frame, the result was that the frame weighed about the
same as a tubular example. This machine is currently raced in the Classic 50 cc class. Alan
plans to build another bike with this frame to take to Bonneville in 2016, and the idea
makes a lot of sense as the majority of the bike can be dismantled and packed into hand
luggage, I look forward to hearing how he gets on.
Tony Dawson raced sidecars in the 60s and is most famous for inventing the Astralite wheel,
a lightweight pressed aluminium wheel which started production in 1977 and by the end of
the 1980s over 1500 wheels were being sold globally per year. As well as designing wheels
Tony Dawson also formed a company called S.C.I.T.S.U. (Selfish Conduct Inhibits True
Sporting Union) in 1978. The company was founded to produce components for road race
bikes. This aluminium frame design was used on a number of Road Racing bikes back in the
1970's mostly using larger engines than this 50cc example. A bike with this frame design
appeared on Tomorrow's World in the Mid. 1970s. Tony patented the design and some think
that if he hadn't the Japanese may well have taken it on, as it is a design that could be
easily automated due to it being a series of aluminium plates bolted together. The ride
hight can be adjusted by changing the vertical plates, and the tank is sandwiched between
the top two plates. The construction is surprisingly strong, but still enables a certain amount
of twist that is needed to maintain grip on a road racing machine.
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Originally Posted by Grumph
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