Dahon Impulse P21 is a Dream Bike

11-15-2004, 07:55 AM

A while ago I posted a thread about the horoscope of a new bike, a Dahon
Impulse P21, that was causing me a lot of grief. However, since the bike
had not been delivered in a rideable condition, but needed further
intervention from a cycling professional to make it road ready, I
deemed, with the help of the forum, that the horoscope could be recast
for the time I picked him up from the shop. This must optimally have
been around 11:30 on November 6th. In the event, I paid for Flyzipper's
assembly at 11:25 and rode my first few yards on him at 11:38. This was
just in time for a cycling holiday I was planning to take from 9th to
14th November in the Touraine region of France where I used to live.

This bike is a winner!

Flyzipper has 20" wheels, weighs 12 kg, and is equipped with a fabulous
21-speed SRAM DualDrive shifter - three speeds in the front hub and
seven on the rear derailleur. It is a whole new world of comfort to have
so light and small a bicycle! After a year of struggling with Behemoth,
a 20 kg Dutch monster whose geometry has never really suited me, I feel
as though I have finally come home. Flyzipper starts in a breath and
rides extremely straight. Weight on the handlebars is minimal. I was
right to choose this model with its straight T-bar handles, as this puts
so much less stress on my wrists than Behemoth's swept-back bars. My
wrists tend to start aching after only about 20 mins on Behemoth. On
Flyzipper, I rode more than 4 hours on my first big day out and didn't
even have to put on my gloves. I feel much more balanced on Flyzipper
for not teetering so high from the ground. And the SRAM is the best
shifter I have dealt with so far. All 21 gears are useable, but most of
the time, I just change between the 3 front speeds. When I have a
stretch of long, clear riding ahead, I up the rear shifter a notch or
two; when the ground is hilly or the paths are shorter or a stop-start
situation threatens, I put the rear shifter into a neutral 4th gear. I
have not yet tried the granny gears but will soon have occasion to do
so. What is great about this system is that it cuts down on needless
complexity. Behemoth has a Nexus 7 shifter, meaning that split-second
decisions have to be made between all 7 gears. With Flyzipper, there are
only 3, but each of those can be modulated through a whole spectrum of
shades when there is leisure.

I am amazed at the speed of this lil critter! He seems to be the fastest
of my bikes. Can it be that the advantage of lightness compensates for
the smaller wheels? My second outing in the Touraine was my first
accompanied cycle. My friend was on a 21-gear bike with 700mm wheels. I
was in 2/5 for most of our flat 7.5 km stint and she was in 2/7, but she
had trouble keeping up with me! We finished the circuit in just half an
hour, despite a nasty head-wind.

The Impulse P21 folds more easily and compactly than the Speed TR,
another model I considered. I worried that the addition of lights would
compromise the folding action, but this didn't happen. OTOH, the counter
did pop off when I had the bike folded. Fortunately I spotted it in time
and didn't lose it, but I now recommend pocketing it before folding. I
made a little mark on the seat-post to show how far I need to pull it
out to have the seat at the right height. As for the front bar, once
adjusted, the folding action affects neither its height nor its angle,
so this does not have to be recalculated every time.

Unlike the Speed TR, the Impulse has a chain guard, and to my delight,
after a week of stopping against lamp-posts and walls, I discovered a
small strut. It does not come with lights, but I discovered from
Behemoth that I hate dynamos anyway. I fitted Flyzipper with lights that
run on ordinary rechargeable AA batteries such as I already use for my
TV earphones and am well equipped to handle.

A few small demerits. It took me a week to figure out how to fold in the
pedals, and I reproach the manual for giving no clear instructions on
that point. (You have to push them _in_, towards their axis, then they
can be pivoted flat.) The magnetic catch that holds the bike together
when folded is rather weak and the two halves easily come apart. The
bike is extremely lumbersome to carry in its folded condition. Unlike
even the heaviest luggage which today almost always has wheels, the
Dahon needs to be hoiked and heaved over the smallest distance. I
quickly learned that, on train platforms, the folding must happen at the
last possible minute, when you are just in front of the door of your
wagon, and you must unfold the minute you alight from the train. At
Tours St Pierre station, elevators are only supposed to be used by the
disabled. I'm afraid I had to disregard this rule, because if I had
tried the stairs with that bike and my bags, I would have risked a heart
attack. (But why anyone should be expected to carry enormous
portmanteaus up and down great flights of stairs remains for me one of
the great ineptitudes of station architecture...)

The baggage rack is small and carrying capacity is limited. I used only
my one small Vaude pannier. I have various over-the-rack double panniers
but they hang too low to the ground. Also, I did nearly kick the pannier
off several times with my heel, so it could not have been any wider.
However, the Speed TR model has a special, high-set baggage rack for
touring that can be ordered for the Impulse as an add-on, should I
project a longer trip.

The most important drawback is that this bike is totally unupported in
France. Unlike Behemoth, who needs practically no maintenance, Flyzipper
has parts that rain and my weight and rougher riding could damage. I was
paranoid about getting a flat. Why are there no local sellers? Is Dahon
one of those American firms that has made a policy not to sell to "Old
Europe" out of redneck jingoism? From the fascinated glances Flyzipper
was attracting from all sides, I cannot doubt that there would be a good
market. The policy of the SNCF, the French Railway System, towards bikes
is hugely incoherent, but suffice it to say that many trips cannot be
made with a full-size bike. On the other hand, few folding models are
available in this generally bike-friendly country, and none with the
touring capacities of my Flyzipper.

I can't wait for the Spring!

EFR
Ile de France