|By James Hepburn
Clive Sinclair's latest attempt to push back the
boundaries of environmental transport has
resulted in the Zeta - the "Zero Emission
Transport Accessory". Unlike its precursors,
the C5 and the Zike neither of which
conspicuously conquered the British roads the
Zeta is not a complete vehicle, but a
battery-operated power-pack which can be added to
most types of bicycle.
Since its introduction in April it has sold
about 5,000, about double the number of Zikes
sold so far.
The colour-supplement advertisement claims
that the Zeta will "take the slog out of
cycling". Beneath the claim is a drawing of
a woman, ponytail flying in the air, joyfully
climbing a steep hill against a savage headwind.
Most days I cycle five or ten miles through
London. Perhaps with this machine I could broaden
my horizons? Perry Cohn warned me not to raise my
hopes too high. Mr Cohn was the mechanical
engineer at Sinclair Research responsible for the
development of the Zeta. I caught him shortly
before he left the company to join the McLaren
motor-racing team. While he fitted the Zeta, he
explained why I was far from the ideal customer.
My weight was the first problem. The Zeta does
not replace the cyclist's legs. It is there to
give assistance. It claims to provide half the
power needed to propel a 12-stone cyclist up a
one-in-ten gradient; my 15½ stone was no picnic
for a 174-watt motor. Another problem was that my
bike, a 12-speed Townsend "Triathlon",
was too fast. The Sinclair machine is designed
for the more sedate end of the market for those
who want to cycle the two or three miles to the
office but are deterred by the hill past the town
The machine itself is a 4.5kg box with a shiny
blue cover which is screwed to the frame above
the back wheel. The box holds a re-chargeable
battery attached to a motor powering a revolving
belt pressed down on the rear tyre. The motor is
operated by a switch on the handlebars. The
battery has a range of about ten miles.
Pulling away from the kerb, my first
impression was of a shove from a divine hand. For
all my bulk, the Zeta had enough power to set me
off from a standing start at the pace of a gentle
stroll. Four hours later, after a 30-mile trip
through London and Kent, my enthusiasm was mixed.
The first of the design faults emerged in
Camberwell. As I rattled over a bump, the Zeta's
cover, held in place only by a Velcro
arrangement, flew off. This happened another four
times during the afternoon.
The second fault waited until Bromley. I
thought that the battery had expired, until I
realised that I had bent the operating lever flat
against its mounting bracket, the equivalent of
having an accelerator pedal on a car set flush
with the floor. I bent it back and rattled on
down the road.
The motor certainly helped on the hills, but
at other times it tended to slow my progress. The
extra weight and the drag of the drive-belt acted
like a brake, while the constant rattling of the
cover gave the sensation of being pursued by a
heavy engineering plant.
My verdict is that the Zeta is of little use
to serious cyclists. However, for anyone who
enjoys a potter on a bike, it may well be a help
and the revised model takes care of most of the
problems I encountered.
The revised Sinclair Zeta is available by mail
order at £144.95, including battery and
recharger (0933 279300). It needs no licence, tax
or insurance and can legally be used by anyone