Speed, at Wilier, is not simply a measure: it is an ideal, a philosophy that has its roots in
solid over time. For Wilier Triestina, speed is not just a technical fact or a number in
wind tunnel: it's Culture.
An approach that combines engineering research, athlete experience, and design sensibility.
authentic passion for cycling and for work, born from craftsmanship and a strong will
to offer future generations an absolute and pure cycling experience.
Filante SLR ID2 embodies this vision. Not just a simple upgrade, but the most advanced expression
advancement of a tradition that starts from the first Wilier aerodynamic models, passes through
experiences such as Supersonica SLR and today arrives to redefine the boundaries of efficiency on the road. Each
detail is born with a clear objective: to put the athlete at the centre, enhancing his position,
sensations and real road experience, to allow him to become faster in the real world.
AERODYNAMIC DEVELOPMENT: BICYCLE AND CYCLIST, ONE THING
Pure aerodynamic efficiency is not enough if the real-world result is not up to our expectations.
driving quality standards. When we decided to rethink Filante SLR, we set ourselves a
A simple but crucial question: how can we raise the performance bar even higher? Together
to the technical staff of Groupama FDJ – Cycling Team, we have analyzed every detail to understand
f
up to where it could push us.
After the achievements made with the Supersonica SLR, it was clear that expectations were very high,
especially on the aerodynamic front. The goal? To create a bike capable of guaranteeing maximum
efficiency even outside of time trials. An ambitious challenge, which included a
paradox: combining extreme aerodynamics and, at the same time, lightness, reactivity and quality of
guide.
Just like with Supersonica, we didn't stop at the chassis. We studied the entire ecosystem.
racing: complete bike, components, accessories and we have put the most important of the
elements: the athlete himself. Because the aerodynamics of the bike alone are not enough: what really matters is the
real speed, which for the cyclist translates into unique sensations and superior performance on
street.
But to develop the new Filante we didn't rely only on racing experience: we
used the most advanced CFD simulations.
Like all the aerodynamic frames developed by our Innovation Lab, Filante SLR ID2 was conceived
following a precise design process, with well-defined stages over time. The project brief is
digitally translated into a 3D model consisting of the frame, fork, and handlebar. A set
of components that is virtually divided into thousands of small cells called in computational jargon a mesh.
All this is needed to submit the design idea to an initial analysis using CFD software.
This software - by solving the Navier-Stokes equations - virtually simulates and describes the
behavior of a fluid (air in our case) around an object. Once the object has been defined,
the physical and environmental conditions in which the object is to be analyzed are decided.
In our case, the air speed is the most important element. At this point, the
The software calculates how air moves over the surface of each mesh cell. The result
obtained defines how aerodynamic a 3D model is. If the results are not as expected,
expected, we are going to remodel the 3D by improving the shapes where possible, trying to optimize the flows and
thus reducing aerodynamic drag. All this in theory.
In practice, things are more complex. One of the first obstacles is computing power:
During a CFD simulation, the computer must solve billions of small mathematical equations - one for each cell of the mesh - in order to best simulate the movement of the air. This is why they are
extremely powerful computers are needed, equipped with hundreds of processors working in
parallel. CFD simulations, therefore, are very expensive but allow great freedom of
experimentation: they allow you to focus on improving many small details, which ultimately
f
ine - added together - make the real difference bringing a substantial evolution in the
product performance.
The first areas of intervention concerned the leading edge, that is, the set of surfaces that
They are the first to interact with the air flow and significantly influence its
behavior. The analysis focused sequentially on the fork, head tube, handlebar, tube
down tube and seat post, optimising geometry and profiles to reduce turbulence.
A correctly designed leading edge allows for a reduction in drag.
aerodynamics and to keep the laminar flow close to the profile for longer, with a clear
improving overall efficiency.
MORE DATA, LESS DRAG: THE NEW FORK AERODYNAMICS
For the fork alone we designed and analyzed different NACA profiles, aerodynamic shapes
derived from aeronautics and mathematically defined to ensure maximum flow efficiency
of the air. Each profile was tested in combination with wheel and tire through simulations
CFD, considering different wind angles to reproduce real-world conditions. The process required three times as many CFD simulations as those used to develop the Supersonica SLR, resulting in an exponential increase in the amount of data to be processed.
This systematic approach allowed us to progressively refine the geometry, until we defined a completely new solution: a fork characterised by a NACA external profile and a flat internal profile, designed to minimise interactions with the wheel and tyre and maximise aerodynamic stability.
When designing the new fork we paid particular attention to the crown cone.
From our experience with the Verticale SLR, we learned that a steeper angle allows for a more homogeneous carbon layup, which increases stiffness while simultaneously reducing overall weight.
With Filante SLR ID2 we have pushed this concept even further: the even more accentuated cone guarantees greater torsional rigidity and superior resistance to stress, improving steering precision in any conditions.
The left fork leg integrates a thin aerodynamic fin that touches the disc and envelops the brake caliper: a partial fairing already successfully tested on the Supersonica SLR, now further refined. Finally, the thru-axle clamping bushing has been completely incorporated into the leg.
right: a solution that combines aesthetic elegance, clean lines and a tangible benefit in terms of aerodynamics and practicality.
THE HEAD TUBE: THIN, CLEAN, FAST
The head tube has been further improved, to make the air flow more smoothly and efficiently.
The leading edge remains faithful to the previous version, but the profile now develops into more tapered and slender shapes, capable of further reducing drag.
As always, at Wilier, technology meets elegance: the brake and control sheaths are channeled directly from the handlebars into the head tube, creating a total integration that combines aesthetic purity, aerodynamic performance, and unparalleled artisanal attention to detail.
NEW F-BAR ID2 HANDLEBAR
The Filante SLR ID2 is born with the new F-Bar ID2, an aerodynamic cockpit completely redesigned together with the technicians and athletes of the Groupama – FDJ Cycling Team. After developing and testing nine types of titanium handlebars, we defined the final OEF (Optimized Ergonomic Flare) version. This is a 3 cm orthogonal flare between the high and low grips which, unlike other handlebars with different widths on the market, does not compromise the ergonomic studies designed by the transmission control manufacturers.
An absolutely exclusive solution that gives the cyclist greater control in a low grip, a more compact and aerodynamically efficient position, and a natural and comfortable grip. The control area features a slight upper rise that improves forearm support in a relaxed position, increasing comfort and stability on long rides without sacrificing rigidity.
Integration with the frame has been optimized by lowering the head tube and introducing new top covers and concave spacers that increase the contact surface, improve responsiveness and ensure aesthetic continuity, while the convex shape of the handlebar reduces the difference in height between the handlebars and the top tube, improving aerodynamics.
For the first time on a Wilier product, the handlebar mounting hardware is completely hidden, enhancing aesthetics, protection from dirt and sweat, and improving aerodynamic performance. The Filante SLR ID2 is also compatible with V-Bar, Z-Bar, and F-Bar ID1 handlebars.
DOWN TUBE AND AEROKIT, THE MOST COMPLEX CHALLENGE
The down tube, always one of the most complex areas from a design point of view, was developed with a specific goal: to have the minimum aerodynamic resistance and reduce the exposure of the water bottles to the air as much as possible.
To achieve this result, we chose a dual-section solution. The upper section, very thin and shaped according to a NACA profile, operates close to the head tube to ensure maximum aerodynamic penetration. The lower section, however, is wider and more enveloping, designed to incorporate and shield water bottles, reducing the turbulence that traditionally occurs in this area.
From the first tests, even using round bottles and traditional bottle cages, the design proved to offer a significant improvement in performance. We decided to push the envelope for greater integration and to further reduce air drag. This is where the Aerokit project took shape, a custom bottle and bottle cage system with a tapered profile and fully integrated into the frame, which acts as a sort of spoiler capable of making the airflow cleaner and smoother.
CFD simulations immediately confirmed our hunch with unequivocal results. With a round water bottle combined with just the Aerokit base, aerodynamic drag is reduced to less than half compared to the Filante SLR ID1. With the complete Aerokit, drag is even reduced by more than two-thirds.
In the CFD visualizations, the analyzed section clearly shows how the new down tube, combined with the integrated system, generates a much more orderly flow inside the main triangle: the turbulence-free area, represented in red, is much larger on the Filante SLR ID2, highlighting a concrete technological leap in terms of aerodynamic efficiency.
AERODYNAMIC SEATPOST AND NEW SHIMANO DI2 BATTERY HOUSING
Designing a truly aerodynamic seatpost is an exercise in precision engineering. A seemingly simple component becomes a daunting puzzle to solve and crucial to the bike's overall efficiency: its impact on aerodynamics isn't limited to its frontal surface, but is amplified through its interaction with the alternating motion of the cyclist's legs.
With the experience gained developing the Supersonica SLR, we already had the right formula: a balance between aesthetics, lightness, and comfort. The new Filante SLR ID2 seatpost is born from this recipe, with a thin and sharp profile (38 mm x 16 mm), which optimizes aerodynamic penetration without compromising rigidity and vibration absorption. CFD tests confirm this: the new section generates significantly less turbulence than the previous version, resulting in a cleaner and more stable airflow around the frame-cyclist system, a central element in the development of Wilier products. This design choice also led us to rethink the placement of the Shimano battery.
Di2, historically located in the seatpost. With such a slim design, an alternative, more efficient solution was needed. The answer came by moving the battery to the bottom bracket shell, enclosed in a resin case secured with two screws.
The advantages are immediate and concrete:
• Accessibility: the battery can be checked or replaced in a few moments, without removing the seat post or changing the saddle height.
• Lower center of gravity: The new position helps lower the bike's center of mass, in synergy with the lowered Aerokit. The result is a more stable, precise, and fluid bike when riding at high speeds.
Finally, a design detail that encapsulates the project's philosophy: the rubber protector for the seatpost clamping mechanism is no longer protruding, but integrated flush into the frame. A clean and functional solution that enhances the continuity of the top tube's lines and underscores the attention to detail, a perfect blend of function and aesthetics.
REAR STAYS: A SILENT REVOLUTION
We chose to preserve the family feeling with the previous Filante, maintaining wide rear stays grafted into the seat tube through a broken line, capable of giving the frame a decisive character when viewed from behind.
At first glance, they might appear similar to the ID1 version, but in reality, they have been redesigned in every detail. Analyses of the dynamic interactions between the seat stays and the movement of the cyclist's legs during pedaling led us to an unexpected solution: tilting the seat stays inward by 2.5°. This seemingly counterintuitive choice showed clear benefits in CFD simulations.
The comparison graphs in the dedicated section clearly show how the combination of the new, lowered bottle cage position and the redesigned seat stays generates a cleaner, smoother flow, with a drastic reduction in turbulence. Once again, aerodynamic flow optimization is based on putting the cyclist at the center: this solution allows us to further increase speed while maintaining the same watts produced by the cyclist.
POWERMETER MAGNET HOUSING: AERODYNAMICS IN EVERY DETAIL
The search for marginal gains also pushed us to rethink an often overlooked detail: the position of the powermeter magnet.
We designed a dedicated recess in the chain stays on the crankset side, designed to optimally accommodate the magnet. Once installed, it is protected by a flush-fitting adhesive, making it virtually invisible to airflow and perfectly integrated into the frame design.
Even if the powermeter is not used, applying the sticker still ensures the same aerodynamic advantages and clean aesthetics of the frame.
This solution, in addition to improving aerodynamics, guarantees effective protection of the magnet from accidental impacts or drops of the chain, increasing the overall reliability of the system.
THE SILVERSTONE WIND TUNNEL VERDICT: MEASURABLE PERFORMANCE, REAL BENEFITS
The new Filante SLR ID2 is the result of a meticulous development process, with numerous testing and data validation sessions in the prestigious Silverstone wind tunnel. Each step was designed to go beyond CFD simulation, translating the project into concrete and measurable results.
The verdict was unequivocal: reality surpassed simulation. In the final test session, the drag reduction for the bicycle alone reached -13.6%, exceeding the -12% estimated by the CFD simulation. Even for the bike + cyclist system, a central concept for Wilier, the data was surprising: from -3.6% CFD to -4.5% real. These data demonstrate how the Filante SLR ID2 design
reaches its full potential under real-world conditions of use.
But we didn't stop at internal validation. We put our bike in direct comparison with five top-of-the-line models from the main World Tour competitors. Only one managed to come close: compared to the others, the Filante SLR ID2 recorded an average CDA that was 2.42% better.
A difference that, at the speeds of professional cycling, means seconds gained, energy saved, and concrete advantages when it really counts: in the race.
The Filante SLR ID2 isn’t just a visionary design: it’s a test-proven bike, built to win, and capable of turning science into tangible benefits for the athlete.
AERODYNAMICS AND LIGHTNESS, THE KEY TO PERFORMANCE
Lightweight remains one of the key pillars for ensuring high-level performance. This principle was always a key focus in designing the new Filante SLR ID2. The result is a bike that perfectly combines aerodynamic efficiency and low weight, an essential combination in modern cycling.
The combination of aerodynamics and lightness enhances responsiveness and efficiency, reducing fatigue and optimizing power management. Performance thus translates into a concrete advantage for the bike-cyclist system, making the Filante SLR ID2 extremely versatile, from the toughest climbs to long flat rides.
In tests conducted on the bike alone, at 40 km/h, a saving of 8.9 watts was recorded with standard bottles and bottle cages and 9.47 watts with the Aerokit; at 50 km/h, these values increased to 19.13 watts and 21.20 watts, respectively. The effectiveness becomes even more evident when considering the combined bike-cyclist system: at 40 km/h, the rider's advantage was 11.51 watts with standard bottles and 14.15 watts with the Aerokit, while at 50 km/h, savings rose to 24.55 watts and 28.80 watts.
Translated into real-world performance, this means that in a 70km time trial at an average of 290 watts, the cyclist would take 1 minute and 25 seconds less with the new Filante SLR ID2 equipped with standard bottles, and even 1 minute and 45 seconds less with the Aerokit.
THE CULTURE OF SPEED, THE CREED OF WILIER TRIESTINA
The Filante SLR ID2 represents the evolution of an idea: giving cyclists the fastest version of themselves. From the NACA fork profiles to the new Aerokit, from the redesigned seatpost to the seamless integration of the Shimano Di2 battery, to the geometry developed with World Tour champions, every element converges towards a precise goal: to offer scientifically validated performance, measurable benefits, and authentic sensations on the road.
But the Culture of Speed goes beyond numbers. It's a philosophy that has guided our way of building bicycles for 120 years. This culture informs every one of our projects, pushing us beyond performance for its own sake toward a conscious pursuit that combines experience, ingenuity, and technology. Our goal is the perfect movement: that harmonious balance between cyclist and bicycle where strength, precision, aesthetics, and function merge.
With the Filante SLR ID2, we transform data into emotion. Numbers aren't the finish line, but the starting point for creating bicycles that truly connect with their riders. This is how we keep true to a promise that has always been with us: to create the vehicle that makes you become the fastest version of yourself.
