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FASTER At 30
kph (19 mph) on a conventional bike, 80% of the
rider's energy is wasted with air resistance.
But with the riders legs horizontal and the seat
laid back at a comfortable angle, air resistance
is much less. The ergonomic seating position
enables a more powerful pedal thrust, making you
faster off the mark, as well as superior in top
speed as well as less prone to side buffeting on
three wheels. A fairing can make a real
difference.
Tadpole-
2 wheels in front, 1 rear are
the most prominent in commercial trike design.
In general they are better at cornering, have
simpler drivetrains, and are faster at stopping,
but:
Delta
- 2 wheels rear , 1 front are
generally better loadhaulers, and are more agile
at low speed, making them the design of choice
for workbikes. They also can be linked front to
rear to form composite "tandems".
Trike Stability and
Safety- The stability of a
vehicle with only three wheels compared to one
with four is often a cause for concern and
confusion. If you are free to put the center of
gravity and the wheels wherever you want, you
can always get stability, but a trike usually
trades off some stability for practicality. Body
english and/or riding skill with anticipation
then are needed to keep the rider out of trouble
in some situations. Briefly, if you have two
wheels in front, and you put on the brakes, the
weight goes onto the front wheels and you are
going to have stability pretty close to a four
wheeler. In almost any emergency, you can manage
this. With the front brakes on hard, you can
also swerve, and if you overdo it, you go into a
straight (understeering) slide, not a roll. With
one wheel in front, if you put most of the
weight there by braking, you have got pretty
much the stability of a kid's bike on narrow
training wheels. Any attempt to turn with normal
vigor, or even a road irregularity, could dump
you. Any doubters are invited to look up the
insurance rates for Harley trikes, check the law
about ATVs, or gaze at the little metal skis on
the front of the Cushman scooters, designed to
make any roll turn into a straight skid. To get
through hard braking safely, a delta needs most
of its' weight low and to the rear, and if this
is not possible, the length and width have to
increase to give the same angles. A nice battery
pack, or trailer hitch can weigh that back axle
down nicely, as can appropriate cargo. In steady
cornering, this rear weight bias will almost
always produce oversteer at the limit. Sporty
deltas can be ridden, and well, keeping the
limitations within mind and trusting luck to not
find one of the unsolveable situations. If we
want a tall, narrow design, the stability for
fast cornering can be boosted with the addition
of a tilting mechanism. There is less reserve
for wind gusts and inaccurate leaning, but this
is not usually a problem, whereas fast, safe
cornering is an energy-conservation issue.
Tilters are subdivided into three types. Any of
these methods will help either tadpole or delta,
but the overall stability will be affected by
braking just as it is in the upright types, or
even more so if length does not keep pace with
the rise in the center of gravity. Leaning also
makes a trike quite a bit more comfortable on
cambered road edges. The "free-leaners" are
ridden, balanced and steered just like a bike,
except for occasional use of the trike
stability, at stops and, one hopes, when caught
out by a crosswind gust in a narrow lane. The
lean-steer type uses one control to both steer
and lean, so it is either optimized for one
particular speed, or has another control axis to
set the mix of leaning and steering for any
speed. The power leaners can use muscles
(usually relaxed and free-leaning) or motors,
and if the latter, they can be driver-controlled
or robotic.
There are no absolutes in the type of
trike design you employ, so it's "caveat emptor"
or "buyer beware" - insist on a test ride. There
are many ideas which prove these concepts wrong,
Your Mileage Will Vary - here is a list of
recumbent trike manufacturers: http://www.ihpva.org/SourceGuide/Vehicles/index.html#Recumbent
Trikes and a group of do it
yourselfers including free plans for a
trike:
http://www.ihpva.org/Builders/.
Another excellent source of information is RCN
((http://www.RecumbentCyclistNews.com) .
you should be prepared to pay a little more for
your extra wheel (less than an new auto, but
more than a new mountain bike - these are mostly
hand-built by devoted craftsman, and not turned
out in a factory in Taiwan. If you do purchase a
foreign made trike be prepared to 1) wait, 2)
Currency Issues, 3) Shipping Costs, 4) Import
Duties. Patience is the key word when dealing
with any manufacturer - foreign or
domestic.
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