Recumbent News

Rec-Tech
The TerraCycle
Fold-Forward Stem
Pat Franz is the man behind TerraCycle,
Inc., a recumbent and special-needs bicycle
manufacturer in Portland, Oregon.
He specializes in designing and building
bikes, parts, and accessories that are on
the cutting edge of technology. One of his
special-needs trikes powered a rider to two
silver medals in the 2000 Sydney
Paralympics.
Seeing a need for a different type of
fold-forward stem for above-seat-steering
recumbents, Pat created the GlideFlex.
This completely new design with several
unique features:
• Smooth bending friction, completely
adjustable from negligible to firm
• No metal-to-metal contact in the hinge
or friction system (it’s silent thanks to
Delrin friction bushings)
• Wraparound steerer clamp to keep the
back of the stem smooth
• Available in a range of riser tube lengths
and diameters— standard is 1” OD and
7” long
• Available in a variety of anodized col
ors (or clear anodized)
• Optional quick-release lever can be used
to control friction—an allen-head bolt
is standard
• Adjustable tilt angle
22 Recumbent Cyclist News 71
by Shari Bernhard
Those are the marketing details. They’re
all true.
Pat requested my assistance in beta testing
a GlideFlex prototype on my V-Rex,
and I happily agreed. Having seen his
work firsthand, I had a feeling that this
was going to be a fine piece of equipment.
I wasn’t disappointed when it arrived a few
days later.
It’s beautifully machined, with the
TerraCycle logo engraved on the side. The
stem comes with excellent, and remarkably
simple, installation instructions, complete
with annotated pictures. Even so, I
didn’t trust myself to install it correctly,
so I enlisted the aid of my mechanic and
friend, Fritz. It took Fritz about three minutes
to look over the instructions and about
five minutes to make the switch. It’s designed
for a threadless headset.
Fritz had some misgivings about the
design. Most notably, instead of a split in
the stem that compresses when the steerer
clamp is tightened, it’s simply squeezed,
which he feared might distort the steerer
tube. He also expressed some concern
about the pivot design, which is comprised
of half the riser tube and half the headset
clamp, with a bolt for the friction control.
It looks like an excellent approach to me,
but then again, I’m no machinist, so I con-
sulted Pat to get his rationale for these
design issues.
Even though it would seem that the
clamp could squeeze the steerer tube and
distort it, the jaws are carefully designed
to exactly match the shape of the tube. It
could be a problem if the shapes didn’t
match, but Pat ensured that the clamping
surface is the same shape as the tube. Additionally,
steerer tubes are fairly thickwalled
CroMoly and not easily distorted.
He tested overclamping, and he was unable
to squish a steerer tube. Pat did his
research. New stems coming on the market
are using the same basic clamping
mechanism. It works well, has a very clean
profile, and virtually eliminates the problem
with clamp arms snapping off.
My first impression is that it’s definitely
sleek looking, and the bending action is
unquestionably smooth and steady, unlike
the sometimes sticky movement of the
original RANS Flip-It stem. It’s only
slightly lighter than the Flip-It, which is
mildly disappointing, and replacing the
pivot friction bolt with a quick-release
skewer eliminates even that difference.
This is not a major issue.
One of Pat’s main design criteria for the
GlideFlex was to make a stem where the
side that faced the rider was smooth, with
nothing sticking out that could catch on
the rider in an accident. This is a solid
improvement over the Flip-It.
After a few rides with the bolt as the
pivot friction mechanism, I requested the
optional quick-release skewer. I thought
it would be more convenient to use a quick
release instead of having to rummage for
my allen wrenches in case I let someone
try out my bike and they preferred a tighter
or looser fit. In Pat’s experience, once the
pivot friction is set to the user’s preference,
it usually isn’t changed. After several
rides with the quick release, I realized
Pat was right—changing the pivot
tension wasn’t necessary after all. I removed
the quick release in favor of the
bolt. It looks more attractive and has a
cleaner profile.
There are two issues that I feel should
be addressed, both involving the tilt. First,
the tilt isn’t as adjustable as it should be
due to the angle machined into the bottom
of the stem riser and its corresponding
surface on the stem clamp. Even with
the backstop bolt screwed in as far as it