Feedbacks on the Concours de Machines 2016: the building of the bike [2/3]
In this article we will talk about the building and the technical choices of our light randonneuse which won the Concours de Machines 2016. We began the building at the beginning of June. During three weeks and until the day before the Concours, Romain and Julien worked together in the workshop to build the machine in time. It is the result of very long days of work - and short nights. With this bike, we wanted to highlight our savoir-faire around the work of steel and the fillet-brazing. You will discover how it was applied to our bicycle.
Each Victoire bike is tailor-made and our light randonneuse is like all of our machines. Proportions and geometry are very important to us in general because bicycle really needs to be a natural prolongation of its rider. The first step of the building of our machine was the fitting of our rider, Matthieu, our communication and marketing manager. For us, it was judicious to chose this absolute fan of cycling. The geometry of the machine was thus made in accordance with his morphology. Matthieu usually rides with a racing position. For our bicycle, we wanted to raise comfort, with a halved handlebar drop comparing to his road bike. The fitting was done in three times to validate perfectly the positions of the different points of contact.
Choice of the material
We decided to work with steel of the highest quality, stainless steel, chosing Reynolds 953 tubing. This material enables us to make the most advanced bikes thanks to its high mechanical features - you can find all the details about it on our website. It offers the best characteristics in terms of performance, solidity, weight and resistance to corrosion. It is also harder to work with it so it was an additional challenge for us.
The top-tube has a 31.7mm diameter, the down-tube a 34.9mm diameter at the bottom. These tubes have a 0,35 mm thickness at the center, what is really few. The bi-oval top-tube enables to « surround » the seattube and to increase the area of welding. The chainstays are oval to save space for the mudguards clearance while the seatstays of 16mm of diameter are conical to get a better filtration of the vibrations.
Technical choices for the frame
The triple triangle
The triple triangle, added to its original estheticism, enables to increase laterally the stiffness of the frame. This gives a better reaction at pedal stroke. This process is difficult to make and highlights our skills of building. The seatstays are machined in two parts and have to be perfectly adapted to the seat tube and to the top tube. These adjustments, made by hand, require a big exactness.
The internal routings
The routing of the cable is internal, as well as for the fork and the frame. This greatly raises the esthethicism and the weight gain is furthermore very light (from 10g per routing). We used indeed for these routings specifical tailor-made tubing in 5/10e instead of millimeter tubes that are generally used. The routing of the brakes durits are 7*5/10 in stainless steel. The routing of brake cable with machined bosses is made up of little stainless tubes 4*5/10e .
The bottom bracket at the BSC standard
The bottom bracket at BSC standard make the frame less demanding than a BB30 or PF30 model.This kind of bottom-bracket is also more reliable.
The headtube of 36mm
The headtube of 36mm enables to save some weight compared to the 44mm. Moreover it matches better the small diameter tubing and the lugs of the fork in stainless steel.
We wanted to make our own dropouts but unfortunately we ran out of time. The little 3D droptuts are the best compromise between the weight, the solidity and the quality of the mechanical junction. We used a classical model from Paragon and we customed it a lot to get something visually harmonious.
The Flat Mount brake mount
The brake mount is made according to the Flat Mount standard. We kept this solution because it enables to fasten the caliper on the chainstays. The caliper is smaller than the one of a Postmount version. Thus the visual harmony is better and the setting is easier. Because it is a new solution, there is no jig on the market which enables the welding of the bosses at the good position. That is the reason why we designed and built our own tool specially for the Concours de Machines.
As the frame, the fork is completely made up of stainless steel with many details on its different components. It was entirely silver-brazed.
The fork crown
An important work was made on the fork crown, totally by hand with file and riffler. We made this for three reasons:
- Save weight
- Get a better fitting of the fork blades in the fork crown
- Give a unique style
The fork blades
The fork blades were specially made by Reynolds for the Concours. They come from the 921 range with a specific bending of 55mm, what enables to have more comfort and more stability. Moreover, the fork blades have a diameter of 15mm at the bottom while it is normally 12mm. This enables to support disc-braking.
Like the frame, the stainless steel dropouts come from the catalog Paragon.
The Postmount brake mount
The Postmount brake mount was made from bespoke parts machined by our subcontractor who builds our hubs and designed specifically for this project. They are in stainless steel and enable to get a big area of contact with the caliper. Thus, they are unique parts.
Eyelets of rack
The fork receives stainless steel eyelets to fix the rack and the mudguard.
The design of our tailor-made stem is a last-minute idea. The aim was to mix the estheticism and our technical savoir-faire. We began with the style of a René Herse stem (double dog), but in steel. For this, we used three Columbus Max seatstays for the central part, the other pieces come from 25CD4S tubing made in France. The stem clamp in stainless steel, specially made for the bike in order to use 5mm screws, are exactly the same as the ones of the seat clamp.
The stem was made in the jig we designed and built in the workshop. We use it for 2 years in our production. We get thus a unique model concerning the conception, the design and the building. The geometry reminds René Herse stems, with a little more originality. The bell, element of security, is directly fastened on the stem thanks to a stainless steel insert.
The rack was built from stainless steel tubing in our workshop. It has a minimalist design. The very simple shape enables to reduce utmost the weight. It also includes eyelets for the mudguard and the front light and also a support for the Swift Industries randonneur bag. It is fastened on the eyelets brazed on the front dropout, and on the central point of the headtube. It only weighs 200g, and it can support a substantial weight.