RCR & RCR PRO : The design process

The latest VAN RYSEL bike: RCR is definitely one of the best-performing bikes on the market in its category: aerolight.
To achieve this result, dozens of experts – researchers, engineers and designers – have surgically optimized every technical aspect of these bikes, obtaining for each one the best ratio of weight, rigidity and aerodynamics.

In this video, we tell you the story behind the design of the RCR.

The RCR is the result of a team work effort, the sum of dozens of individual’s expertise for more than 3 years. And today, we can tell we’ve done great, reaching the perfect balance on between aerodynamism, energy return, and weight optimisation It all started with a clean sheet

We had no history on high aerodynamic performances. Therefore, the choice was made to pitch in with the renowned French Aerospace Lab ONERA. We broke the bike chassis down in 3 main study areas submitting each one of them, in wind tunnel trials First critical area, the head tube, second, the fork,

And the third one, the seat post. A measured air penetration coefficient of 0.0726, makes the RCR one of the ten fastest bikes in the World The French Aerospace Lab ONERA, does aeronautics Research & Development. The Lille Research Center facility, is dedicated low speed aerodynamics specialists, during stall and tailspin conditions.

When it comes to aerodynamics optimisation, we must bear in minds 2 things : Firstly, reduce as much as possible the surfaces that obstruct the air flow, the frontal surface. Secondly, control the air flow to ensure the most fluid runoff with the least eddies. The RCR project origin, was its 2D sections study.

Bearing in mind the stiffness constraints, we ran studies to maximize the sections aerodynamic. 12 mock-ups were generated in 3D printing, reading variations in sections and tube junctions Then we all tested them during wind tunnel trials. in a wind tunnel, the air is sucked up, to generate a laminar airflow, eddy free.

The bike is placed on a highly sensitive weighing scale, which measures the different applied forces, from the airflow on the bike. At different speeds, and different angles of incidence Cross referencing the multiple trials data, we managed to isolate the results of every single section variation, and preserve the respective pros.

This allowed us to reach a measured air penetration coefficient of 0.0726 To maximize the energy output, stiffnesses required to be well balanced. Data read that it exists multiple stress concentration areas during the different race events. Repetitions on test bench have allowed us to adjust the values. A head tube moderately stiff,

To provide a precise and stable bike handling. A very stiff bottom bracket, to transfer the maximum amount of power and a rather flexible chainstain, to round the global chassis balance off. As soon as the chassis design has been validated, begins an iterative process on the carbon fiber lay up.

What is the carbon fiber lay up ? It is all the carbon pieces that makes up the chassis We are very attentive with regard to the fiber type, its orientation, and its positionning on the chassis. It is roughly 500 pieces for the RCR. For every single iteration,

We run a full range of tests. For the test pedalling forces, the standard requires to comply with 100 000 cycles test. We go way further than the standard, to ensure the reliability for the chassis lifespan. Then, there is also the impact trial. it allows to simulate sidewalks or potholes accidental collisions.

We had very high expectations, for the stiffness and the weight, making no compromises on the chassis reliability. It is no less than 4 prototypes, that ran through the entire bench test procedure, to reach our goals. During the first ride, we noticed that a slight thing was missing,

To achieve the perfect balance Ultimately, we made a 15 grams concession to the initial goal, to achieve the perfect balance, on between weight and energy output. The UCI standard minimal weight is set to 6,8kg The will was to be the nearest, while preserving the aerodynamism and energy return performances.

We’ve had to think different, gaining gram per gram The optimisation was realised in 3 main steps : The carbon fiber selection and the laying up, a severe weight reduction of all the spare components, and the refining of the paint and glazing process. An uncompromising run-up,

Bringing down the overall bike weight down to 6,826Kg The lay up consists of carbon fiber layers superposition, tied up together with resin. depending of the carbon fiber type, and its orientation the lay up will react in a specific manner, to the applied forces. To meet the UCI minimum weight restriction,

First thing was to introduce high modulus carbon fiber 60 tons. We applied them relevantly, where the stress concentration is peaking, we manage to reduce the material usage, to gain up around 100 grams. The 60 tons carbon fibers, represents more or less 5% of a RCR lay up

Second thing, a severe weight reduction, of all the spare components. The seat tube clamp, the derailleur hanger, the wheel axles and the titanium hardware. To gain up an other 80 grams. Last thing, the cosmetic optimisation. The RCR offers 9 colorways, 3 of them especially designed with a weight target.

We’ve had to revise our painting and glazing process, integrating weight checks For the painting process : We start from a raw from factory chassis, on which we applied a putty. After sanding, we have a very soft surface finish. This allows the epoxy fixing coat application, for a perfect painting settlement.

The epoxy fixing coat application is sanded again, before the final painting. water decals, and glazing. For the 3 optimized models, we chased down all superfluous grams. it is 30% less epoxy, with a relevant application, where the carbon fiber layers overlay. A thinner painting and glazing coat, thanks to a manual application.

Minimalist design choices, with visible carbon fiber layers. At last, the decorations. We replaced the usual stickers, by ink transfer water decals. Cosmetic overall, we have gained up around 50 to 100 grams, depending the colorway.