1967 Sidecars - A Scholarly Treatise - 6-Page Vintage Motorcycle Article

Description

1967 Sidecars - A Scholarly Treatise - 6-Page Vintage Motorcycle Article
Original, Vintage Magazine article
Page Size: Approx. 8" x 11" (21 cm x 28 cm)
Condition: Good
Anyone fortunate enough to have at-
tended European Grand Prix events
will probably have noticed that, following
such mundane displays of virtuosity as Mike
Hailwood riding the Honda 6, the spec-
tators really start to sit up and take notice
when the sidecars are wheeled out onto
the grid. Perhaps the most sensational of
all forms of racing that employ engines,
it warrants a world championship of its own,
and it has reached the point where, in Eng-
land at least, complete programs ore some-
times devoted to it.
The appeal of sidecar racing undoubtedly
lies in the perfect coordination needed be-
tween the driver and passenger, and the
display of high speed gymnastics required
of the passenger whose job is to insure that
the outfit remains on an even keel. Because
a sidecar outfit is a bastard piece of machin-
ery constructed in defiance of all natural
laws, it introduces certain problems and
hazards that are unique to it- Also, because
of its essentially schizophrenic nature,
which demands two totally different corner-
ing techniques depending on whether it is
going to the left or the right. It is intensely
exciting to watch, particularly in cornering
fast with other sidecars.
A long time has passed since the sidecar
was used as a method of passenger trans-
portation in America, but it has only re-
cently started to disappear from the scene
in Europe having been superseded by the
products of Volkswagen. Fiat, Renault and
the British Motor Corporation. Its heyday
was probably during the '20s, and in those
days it was raced in relatively standard
form with the passenger doing his best
within the confines of the boat-shaped body,
which gave the whole performance a Key-
stone Cops atmosphere.
By the early '30s the sidecar itself had
given way to a bare platform equipped with
an assortment of grab handles and toe
holds to enable the passenger to bring
his weight to bear,.but the outfit was still a
rood racing motorcycle, usually a Manx
Norton, with the platform sidecar attached.
This situation continued after the war until
Eric Oliver brought some science into the
sport during the early ’50s. The tall rangy
Oliver was the world champion during the
years 1951 to 1954, and he contrasted
sharply with his passenger who was the
diminutive and bearded Denis Jenkinson—
motorcycling's Toulouse-Lautrec
Oliver had strong backing from the Nor-
ton company, which was then at the top of
its racing form, at least as far as the side-
car class was concerned. His approach was
to make the outfit more of an integral unit
and to fair against wind resistance, which
he claimed raised the maximum speed im-
mediately by 10 mph. Connoisseurs of the
sport maintain that the Oliver years were
the best years because the machines were
very fast, but they were relatively unman-
ageable so that the driver appeared to be
locked in mortal combat with the machine
throughout the race.
The next step was the introduction of the
"kneeler" which is almost universal today.
As its name Implies, a kneeler is con-
structed so the driver reclines with most
of his weight on his knees The advantage
is that the center of gravity becomes very
much lower, and the frontal area is reduced.
GP events are limited today to 500cc
capacity, and the sport is dominated by the
horizontally opposed BMW twins. How long
this situation will last is anyone's guess
because the Bayerische Moterenwerke is
much more interested in its European police
motorcycle business than it is in sidecar
racing and, in consequence, the support the
company gives in parts and equipment is
dwindling. In England, which has always
been the center of the sport, sidecar racing
is healthier because at many events a top
limit of 1300cc is imposed so that other
suitable engines of greater capacity can be
developed, and are being used.
The bask layout of the BMW engine
makes it a natural for sidecar racing be-
cause of its lack of height. Furthermore,
the engine con be mounted without any re-
gard for the possible grounding of cam
covers in a turn, as is the case when the ma-
chine is used for solo racing. Some English
drivers remain faithful to the single cylinder
Manx Norton engine, but it is a vast hunk of
machinery and difficult to accommodate
even when laid nearly horizontal. Most
English drivers use 650 BSAs or Triumphs,
with an occasional 650 Norton. Racing
success depends more upon reliability
than speed.
Adequate cooling is a vital consideration
because the engine is called upon to work
for harder than it was ever intended to
work. Furthermore, cooling is complicated
by the fact that fairing is not restricted as
in solo racing and, of course, the require-
ments for an efficient shape are in direct
conflict with the requirements for efficient
engine cooling. Carburetion presents anoth-
er problem because of centrifugal force In
cornering, and it is common practice to use
two weir type float chambers, one on each
side of the carburetor. There was a period
a few years ago when fuel injection was in
vogue for certain circuits, and particularly
on the BMW machines, but this seems to
have died out and Dellortos are not normal-
ly used on BMWs. To assist in lowering the
center of gravity, the fuel is carried in a
tank mounted in the sidecar from where it
is pumped up, usually by an electric pump,
to a small gravity tank over the carburetor
On the English machines the drive from the
engine is often taken through a Manx Nor-
ton gearbox because it is an exceptionally
robust unit offering a good selection of
close ratios.
Frame design seems to be a matter of
taste, but a conventional motorcycle frame
is useless As we have already noted the
outfit Is designed and built os a unit, al-
though some drivers bolt the "chair" to the
machine so that they can be separated for
ease of transportation. As in automobile
racing, the frame is normally a multi-tubular
structure designed to combine strength and
rigidity with light weight, and the tubing is
normally of relatively low tensile strength
which is readily available, cheap, and easy
to work compared to the more specialized
aircraft materials.
When considering the layout of the frame,
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