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FLOWING LINES
The frame is designed to the simplicity of one triangle.
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FRONT HUB
Quality front hub with quick release.
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FRONT AND REAR BRAKES
Quality SRAM AVID BB7 front and rear brake, smooth
powerful braking, for long pad life, zero drag and instant
easy adjustment. Wheels remove easily without throwing out
adjustment. The oversize brake pads on the 140mm disk and
20”wheel provides stopping power equivalent to a 180mm
disk on a mountain bike.
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CUSTOM FORK
Custom chromoly fork will take anything you can throw at
it and still give a smooth ride with great feel through the
handlebars.
QUALITY RIMS & TIRES
Alex double wall aero shaped rim DA16 front and rear.
Kenda K-West 193, 100 psi tires at 20" x 1.5"
(front) and 26" x 1.5" (rear).
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CABLING
Concealed cabling keeps things tidy and out of your way.
Control cables are hidden in the front tube from the
handlebars down to crank, and then out of sight along the main
tube.
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STEERING
Universal joint driven steering column provides excellent
feel and control in a compact convenient form.
Universal joint steering was an integral part of the race
winning Mochet competition bikes of the 1930s, before rule
changes excluded the design. By reintroducing this smart
system SIGMA loses the awkward tiller effect found on other
long wheelbase recumbents; and allows a compact overall form,
that lends itself to the use of an energy saving front
fairing. By mounting the front fairing to the frame rather
than the front fork, safety and stability at speed in various
wind conditions is also enhanced.
The u-joint has zero backlash and weighs in under 100
grams.
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SEAT CONSTRUCTION
Proven Cruzbike type seat from pressed alloy with
two-layer cushions under breathable polyester seat covers.
The seat has a lean and mean form, even the seat mounting
bracket is minimalist, keeps the seat height down and is
shaped to cut through the air.
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LEG ADJUSTMENT
With a simple hex socket (Allen key), the seat pan can be
easily moved along the long top tube to accommodate the
longest or shortest legs.
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SEAT BACK ADJUSTMENT
Dual struts adjust with a hex socket, allowing an upright
posture for touring or beach cruzing or a more laid back
style for chewing up the miles.
A nice closed riding position is possible for getting
plenty of power down.
Sigma uses clamps rather than pins on the seat back
sliders, so there is no danger of lost parts.
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CRANK AND PEDALS
The bike is standard with an ISIS bottom bracket and
rubberized platform pedals. Most riders will swap out to some
kind of clip-in pedals in time.
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COCKPIT
A reasonable step over height is achieved by a bend in the
top tube. The cockpit is compact and tidy, with the
handlebars connected to the steering column via a standard
stem.
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FAIRING
The Sigma and a front fairing is a match made in heaven.
Gone are the days when a front fairing on a long wheel base
is attached to the fork and handle bar. On Sigma it attaches
to the frame to create a solid mounting. A lightweight low
cost custom fairing is available and is guaranteed to improve
high speed performance as well as deliver the comfort
benefits you are looking for.
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REAR DROPOUT
The design theme is carried into the dropout, gracefully
providing the mounting points for the rear brake unit as well
as the struts supporting the seat.
REAR BRAKE
Like the front, a quality SRAM AVID BB7 is fitted to the
rear. Using the snail cam adjuster (see next) to release
chain tension, the rear wheel removes easily without throwing
out brake adjustment.
Rear disk matches the front at 140mm. On the 26”
rear wheel it provides firm braking with reduced chance of
lock up.
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SNAILCAM CHAIN ADJUSTMENT
Snailcam adjustment makes it a breeze to keep the chain
tensioned and the wheel aligned. The cam stays on the axle
and is never lost. When the axle nut is loosened, the snail
cam rotates to allow the axle to easily slide forward to
disengage the chain so the wheel can be removed in seconds.
The snail cam also defines the fore-aft movement of the
axle. This also governs the movement of the disk, ensuring
the brake pad is always positioned over plenty of disk
surface.
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CHAINLINE
A chain line free from rollers, straight, quiet, nothing
to maintain or clean. Nothing extra to drag in the breeze.
Every roller and dérailleur, every extra thing
added to the frame makes it harder to push the bike through
the air. So we removed them all, by way of an IGH –
Internally Geared Hub, see next.
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GEARBOX
Sigma is fitted with the highly respected SRAM i-motion9
internal planetary gearbox, for instant smooth changing when
in motion or when stopped. The SRAM hub is known for its
easy, instant adjustment and low maintenance. The hub
provides 340% spread of equally spaced gears: 17%, 14%, 14%,
14%, 14%, 14%, 14%, 17%. Gear inches are 30 to 101. Gain
ratios are 2.5 to 8.3. Gearing may be altered by swapping out
to other chainrings.
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CLEAN DETAILING
The bike abounds in thoughtful clean detailing, pictured
here, top tube connection to the rear triangle. The vertical
member is a thin web slicing through the air. The bolt shown
is for removal of the top tube and seat.
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SEMI FOLDABLE FRAME
Frame top tube and seat can be removed to allow the front
tube to fold down, making for easy transportation, even on
airliners.
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FRAME
7005 alloy main tube to provide lightness and stiffness,
with chromoly front and top tubes, for a smooth comfortable
ride.
This is a rugged touring or commuting frame.
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