We saw the full potential of the
Retül and Computrainer technologies and we sought to
make them work together and extract the maximum
We developed our own tools
to complement these two key technologies. We developed a very advanced
system to simulate riding conditions with as much fidelity as
possible. Our own original design and manufacturing of
this rig allows us to
hold the bike and rider in a stable position when
under heavy loads. We affectionately named it the Fit Rig.
The role of the fit rig is very important: Retül measures
the cyclist's body postures to
within 1mm of accuracy. With this level of accuracy, extraneous
data and data noise must be filtered out for the
collected data to be actionable. We must measure the organic movement
of the rider on the bike, not the bike moving around. This
is a requirment that your typical trainer's
front wheel-block can't provide: it slides around too much. The fit rig,
on the other hand, provides a
noise-free data platform with high fidelity to riding
Retül motion captures must be done at
high power levels to be significant, the stability of the
rig under high loads is critical. We tested the system up to
1,000 Watts of power output without a hint of a movement. For
out-of-the-saddle data capture for climbing and track
sprinting bike fit protocols, the fit rig is the
only platform you can trust.
Additionally, from an operating
accuracy point of view,
relies on a perfect
horizon - blindly. It means that the bike has to be perfectly level
axle-to-axle. Retül calculates angles to plumb and a non-leveled
bicycle would return data that's incorrect and
non-actionable - we call it garbage data.
Our rig assures the quality of
data by being perfectly plum by
design and thanks to an
array of calibration tools. It suspends the bike from its axles,
normalizing it to the horizon, no matter what bike type.
Regardless of the wheel
size (650c, 700c, 24", 26", 27.5", 29"), the bike and rider
are always perfectly level.
It accepts all kinds of bicycles:
road, tri, mountain bikes (including Lefty, RS-1, Thru
Axle), cross, track, etc. and a wide range of sizes.
Since we are sought after by many juniors, the fit rig
can accommodate as small as 24in wheels and race
bicycles for kids as young as 7 years old. See here the
It's a thing of beauty -
quite possibly the only one of its kind in the world.
Our Fit Rig was born on a simple
piece of paper, straight out of the mind of our founder,
and Master bike fitter Steffi.
One of the motivations for its
existence was the very basic necessity for fit to be
successful: a level bike.
This was her thought processes:
see many fitters using the wheel block that came with
their cycle-trainer - I've seen people even use books
under the front wheel! I
don't understand why. The wheel block is not designed
for bike fitting: it's not level; it's not solidly
affixed to the ground. Bike fitting protocols have
the specific need for the bike to be perfectly level
-and stable. When fitters use a wheel block, they are
really setting you up for failure. Customers cannot benefit from the fit done in this fashion. That's
not acceptable. I wasn't going to let this happen to our
additional motivator was the need for a stable platform.
"I realized that with Retül's
1mm measuring accuracy, I needed to create a supporting
apparatus that would help me separate the noise of the
bike's induced secondary motion from the organic
movement of the rider. We have to take motion capture data at high power
level to be meaningful. Everyone pedals pretty when they
are comfy. We learn nothing from that. But with the rider at high power
output we put a lot of
stress on the fit rig. So, I designed the apparatus to
be very stable. This way, the
collected data is accurate and actionable. We can't accept bad
data. The success of the fit depends on it."
And so the bike fitting apparatus,
AKA the Fit Rig, came to life from these very important
It went through stages of
development and growth. It took input from our talented
fabricator and from our customers. It had to keep up with its
developer's imagination and the growing complexity of
our customer's needs.
"This is a
product that's completely transparent to the customer.
It's expected to do its job as intuitively as its
functionality appears to them. But it deserves a lot of
attention, because the fit rig is what allows me to do
what I do best for you."
Much attention was devoted to making
specialty parts to allow for a wide-range of bicycle
sizes and types.
studied many bikes and components. We developed the fit
rig with modular and replaceable parts, so it could
transform to accept the many variations in bicycle
design. Ad-hoc parts had to be developed to address the
challenges of ever-changing fork and wheel attachment
points. We work with a wide range of rider, from very
young to very tall. The fit rig had to keep up with all
of that. The latest challenge is with fatty and
plus-sized mountain bikes."
The opportunity for the fit
rig to be also an information and media center
became apparent shortly after the first prototype was
build. In version 2.0 the fit rig was outfitted with a
20in LCD monitor and a laptop PC station. A large boxed
fan was introduced for rider's comfort.
"I wanted my customers to see
the data I see. This way, I can make you part of your
bike fit; get you involved. I can explain each step of
the bike fitting process, helping you understanding what
I am doing and giving you the opportunity for active
feedback. It also helps quantify the improvements from
each change in your position. It's very neat."
In version 3.0, the fit rig
had grown to two side-by-side 22in wide-screen LED
monitors with two laptop PCs, a Computrainer command
center and a tool tray for a full complement of bike
fitting tools at our fingertip. The boxed fan location was further
improved to accommodate the many cooling preferences of
tests, re-designs and improvements, the fit rig came to exist as
it does today: the perfect complement to bike
fitting and performance testing.
Come test it for yourself!
A sizing or fit bicycle is a
must-have piece of equipment for any bike fitting
operation that wants to be a legitimate bike fitting
business. It's the foundation for sizing customers
looking to buy a new or used bicycle. It's
the cornerstone of pre-sale consultation services.
If a bike fitter doesn't have a
sizing/fit bicycle (or knows how to use it), then it's not
a reputable business.
"Even though we don't sell
bicycles, much of our activities revolve around
advising customers on the right size and geometry.
Exactly because we don't sell bicycles, our bike sizing
services are sought after for a completely unbiased
When we were faced with the decision
of purchasing a sizing/fit bicycle, we searched all
commercially available products.
The need for developing our own
custom sizing rig arose from
the realization that there is a gap in these commercially
available sizing/fit bicycles and the advanced features
we felt are needed to properly size modern bicycles.
Our founder, owner and senior fitter Steffi
decided to develop a sizing technology to overcome the
common limitation of all currently available sizing/fit
bicycles: the simulation of the head tube angle and seat
"All commercially available
sizing/fit bicycles are adjustable only in 2D:
horizontally and vertically. They forgo the ability to
emulate angles like the head tube angle and the seat
tube angle because it's more difficult to engineer and
more expensive to fabricate. Some of these sizing/fit
bicycles look very sophisticated. Some are controlled by
servo motors connected to a computer. They look very
fancy. But that doesn't overcome the underlying
limitation. Some attempt to use software to calculate
post-fit the angles. It doesn't work. It's just
Our fitter knows well. We developed
our own proprietary software, Dream Bike to
attempt overcoming this issue with more sophisticated
algorithms. We introduced a very advanced stem emulation
which accounted for many stem production variations. Our
sizing rig in version 2.x was 2D and relied on our
software to predict head angles. It was good, but not
great. We saw the software predictions get to within
2-3mm of real life. That margin of error is the
difference in one size in a bike (hint: look how the
reach and stack vary by size). This observation was our
motivator in developing our own sizing/fit bike
technology. We discuss this further in our
bike sizing article
and in our custom
The ability to simulate the head tube
angle is vital in determining the right stem length and
rise as well as the correct handlebar reach. The sizing
rig can emulate any head angle and even the headset and
spacers set up for a hi-fidelity bike analog.
During the sizing session, the length
of the stem is used as a check point: if the stem is too
short, it means the geometry being tested is too big;
too long and the bike is too small.
For pre-sales consultation, the head
angle emulation allows us to complete the sizing process
with a spec sheet that includes the correct length and
rise of the stem, so the bike can be spec'ed this way.
For customers looking for advanced aero bikes, this is a
major cost saving feature, as it allows to spec out the
size of the integrated aero bar+stem combination. These
sophisticated aero bars are expensive to replace and
highly proprietary to each brand. Knowing the right size
can make a big difference in cost and waiting time.
The ability to simulate seat tube
angle is crucial in the assessment of the crank length.
These two parameters are locked in a performance dance
that must be closely managed to avoid the potential for
injuries and to maximize performance.
Because we are sought by customers
who travel world-wide to get fitted and can't bring
their own bike, the ability to offer a high-fidelity
bike emulation is vital in their success to take their
fit back home and transfer it successful to their bike
while thousands of mules away from us.
It's a real game changer.
"What this size rig does is simply
amazing. Coupled with the Retül motion capture
technology, it's such an advanced tool, we can use it to
simulate any bike, any size. It's so powerful, we can
design a custom bicycle literally underneath you, sized
for the way you interact with it."
The Size Rig can transform itself and
simulate any bike model geometry and size: Road, Tri,
Mountain. We can input all the relevant bike geometry
specifications of the model(s) you want to test out:
Seat Tube length, Top Tube Length, Head Tube Reach and
Quite possibly the most advanced sizing/fit bicycle
because of our unique, proprietary engineering of the
front-end: the only of its kind with variable head
It is so sophisticated in its
flexibility that it can be used to custom design a bike
to your body specifications.