Issue Six - Spring 2013 - Electric Bike Magazine
Issue Six - Spring 2013 - Electric Bike Magazine
Issue Six - Spring 2013 - Electric Bike Magazine
Create successful ePaper yourself
Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.
+ON TEST<br />
clicks neatly into its socket on the<br />
handlebars, and offers four power<br />
modes with three levels of assist in<br />
each – overly complex perhaps, but if<br />
you’re like me you’ll leave it on full<br />
blast mostly, anyway. The display is<br />
good and clear, with the usual speed,<br />
battery status and distance displays.<br />
The Bosch drive is fitted with a<br />
pulley for the Gates belt drive system,<br />
which runs without oil or grease<br />
lubrication back to the rear hub. It’s<br />
almost unaffected by mud, and won’t<br />
go rusty like a chain which gets wet,<br />
so it’s a promising choice for an MTB.<br />
The belt is also lighter than a chain,<br />
and Gates claim excellent durability.<br />
It’s especially good for a crank drive<br />
e-bike, as these can be hard on chains.<br />
The hub which it drives is the<br />
NuVinci N360. NuVinci are the<br />
only manufacturer of continuously<br />
variable drives for bikes – unlike<br />
conventional gear systems, there are<br />
no steps between ratios. Instead, you<br />
can vary the ratio continuously, by<br />
twisting the handlebar grip, over a<br />
range of 3.6:1. This is about the same<br />
range as a single-chainring derailleur<br />
system. The clever display on the<br />
handlebar control shows instantly<br />
which gear you’re in via a line that<br />
goes flat (for high gears) or hillshaped<br />
(for low ones).<br />
The technology is now well proven,<br />
and after several years of production<br />
these hubs have a reputation for<br />
toughness, even on cargo bikes and<br />
other heavy duty applications. Good<br />
for off-road use, then. The only<br />
question mark about the NuVinci is<br />
efficiency: reliable numbers are hard<br />
to come by but it’s generally thought<br />
to concede only a little to a clean<br />
derailleur drive.<br />
The hub is mounted in heavy duty<br />
adjustable dropouts (for setting belt<br />
tension) which, like the rest of the<br />
frame, look solidly made to withstand<br />
some off-road abuse. One rather minor<br />
criticism is that there are no bottle<br />
cage mounts provided.<br />
The rest of the equipment on the<br />
MX is high quality stuff. There are<br />
SRAM Elixir hydraulic disk brakes, a<br />
good set of suspension forks (Rock<br />
LEFT: The Bosch drive<br />
system is neatly built into<br />
the frame, and is fitted<br />
here with a pulley for the<br />
belt drive rather than a<br />
conventional chainring.<br />
BELOW LEFT: The<br />
belt drive needs no<br />
lubrication and is almost<br />
maintenance free. Note<br />
the sliding dropout<br />
system, clamped with two<br />
bolts, which allows you to<br />
adjust belt tension.<br />
BELOW: The control unit<br />
clicks into place with a<br />
quick twist, and provides<br />
a clear readout.<br />
Shox Sektor RL), and wheels shod<br />
with grippy 2.4"-wide Continental<br />
MountainKing tyres.<br />
One jarring detail was the dynamo<br />
lighting system, a quirk of the<br />
German road traffic regulations,<br />
which make such things compulsory<br />
for bikes over a certain weight. This<br />
is clearly something of a token<br />
gesture here, with a basic bottle<br />
dynamo. <strong>2013</strong> bikes will have a neater<br />
system fitted, anyway.<br />
The dynamo system may also<br />
account for some of the difference<br />
between the weight quoted (23 kg)<br />
and what we measured: 25.0 kg, both<br />
including the battery. It’s rated for<br />
an impressive 140 kg maximum rider<br />
weight.<br />
» OFF THE ROAD<br />
If, like me, you’ve not ridden off<br />
road for a while, the first ride on<br />
the MX will be quite an eye-opener.<br />
Setting off up a rough, muddy track<br />
it was quite remarkable how those<br />
fat, knobbly tyres both grip through<br />
the muck and cushion the ride. The<br />
wide handlebars provide the leverage<br />
to hold the bike on course even as<br />
the front wheel is slipping around<br />
over ridges and tree roots, with the<br />
suspension forks smoothing the worst<br />
of its impacts.<br />
With all this going on, I’d almost<br />
forgotten the Bosch power assist: it<br />
was adding to my leg power smoothly<br />
and unobtrusively. As a ‘torque sensor’<br />
type drive it measures your effort and<br />
adds to it, so it feels like your legs<br />
are supercharged, without any sense<br />
that it’s taking over. So you retain<br />
the ‘feel’ and ability to finesse the<br />
power delivery to manoeuvre the bike<br />
around obstacles.<br />
What it does remove is the pain and<br />
effort, leaving you to concentrate<br />
rather more on your technique (in<br />
my case, staying upright!). Obviously<br />
this is the case on hills, but also for<br />
those short bursts of power which you<br />
need to restore your momentum or<br />
regain balance.<br />
The drive does have a slight buzz<br />
to it, especially if you spin the pedals,<br />
but it’s not enough to disrupt the<br />
off-road experience. Nor did I find the<br />
bike’s extra weight much of an issue<br />
when descending – as a fairly cautious<br />
off-road novice I wasn’t exactly<br />
pushing the boundaries, of course, but<br />
it seemed to hold its line well down<br />
singletrack trails, with the suspension<br />
12 <strong>Electric</strong> <strong>Bike</strong> <strong>Issue</strong> 6