Issue Six - Spring 2013 - Electric Bike Magazine

+FIRST LOOK
The Sunstar electric
bike conversion kit is
unusually versatile,
fitting at the cranks and
offering a lively torque
sensor-controlled ride.
We tried it pre-fitted to a
Dahon Briza folding bike.
Sunstar iBike SO3
The kit comes in three main parts:
First is the 3.2 kg motor unit, which
comes with a choice of chainrings (39,
42, 48 or 52T) and fixing hardware.
Then there are three battery options,
using cells from Sony or Panasonic:
2.5 Ah (seatpost mount), 9 Ah (bottle
style) and 16 Ah (rack mounted), all at
24 V and including mounting racks and
hardware. An 11 Ah bottle style pack
is ‘coming soon’. Finally, the handlebar
control is a simple one with just on/
off, battery level LEDs and power mode
buttons. It would be nice to have a
more informative display as an option.
The crank fitting means that the
Sunstar can be used on bikes where
hub wheel conversion kits might not
work so well. This includes various
tricycles and cargo bikes, and any
machine where the wheels are already
‘occupied’, perhaps with hub gears or
hub dynamos.
For this first look, we tried a well
used Sunstar demonstrator: a Dahon
folding bike fitted with the system by
the distributor, and using the large
16 Ah battery in its purpose made
rack. This didn’t affect the bike’s
folding action, though it made the
folded package somewhat larger. The
motor also prevented the seatpost
fully extending down through the
frame, as it could on the unmodified
bike. This was not a problem for me as
a taller rider, but it also adds to the
folded size. But sometimes you just
have to accept minor disadvantages
to get major benefits…
And the Sunstar did deliver! With
a gentle buzz it amplified my efforts
smoothly and responsively, working
just as a good torque sensor drive
should to make the rider’s legs feel
supercharged. It still feels like normal
cycling, but without such an effort.
The bike’s three speed hub gear
didn’t offer a huge range of ratios,
but with electric assist to help it was
more than adequate for the modest
hills at my disposal around York: I
BELOW: The Sunstar kit fits neatly below the
bottom bracket on the Dahon frame.
still had to do a bit of work, but the
strain was taken out. At the other
end of the speed spectrum the limited
gear range meant I was spinning
the pedals rather to exceed 15 mph
when the assist fades away. As
your pedalling speeds up, the noise
increases in pitch, but that’s the case
with any crank drive I’ve tried.
We’ll look forward to a longer test
in due course, but first impressions
are very positive. It all seemed well
made, and I liked how the battery
charger connector clicks into place
magnetically – a nice touch.
Prices vary according to
configuration but as a basic example,
the motor with 9 Ah bottle battery
would be around £1150. That’s a fair
bit more than for non torque sensing
hub motor kits (which have their own
merits of course) and it’s close to the
cost of some complete crank drive/
torque sensor bikes. Then again, might
it not be more rewarding to fit the
Sunstar to a valued existing machine
and extend its – and your – cycling?
Peter Eland
Manufacturer: www.sunstaribike.com
UK distributor: Sparticle: Tel 01223
926111 or see www.sparticlebikes.com.
Dealers able to fit the system include
The Electric Transport Shop, Bespoke
eBikes and others.
32 Electric Bike Issue 6