{"id":8253,"date":"2021-12-08T17:00:43","date_gmt":"2021-12-08T16:00:43","guid":{"rendered":"https:\/\/cyclesmanivelle.com\/throwback-our-cdm21-bike\/"},"modified":"2026-11-10T17:06:29","modified_gmt":"2026-11-10T16:06:29","slug":"throwback-our-cdm21-bike","status":"publish","type":"post","link":"https:\/\/cyclesmanivelle.com\/en\/throwback-our-cdm21-bike\/","title":{"rendered":"THROWBACK – OUR CDM21 BIKE"},"content":{"rendered":"\n
← <\/span>La Transpyr\u00e9n\u00e9es 2021 seen by Martin<\/span><\/a><\/span>MANIVELLE , OFFICIAL PARTNER OF THE TMV \u2013 Pascal Chabanse\u2019s interview<\/span> →<\/span><\/a><\/span><\/div>

THROWBACK \u2013 OUR CDM21 BIKE<\/h1><\/div><\/div><\/div><\/div><\/div>\n\n
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We have both been travelling by bike for several years, and the way we approach our adventures keeps evolving.<\/em><\/p>\n

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As cyclists, our cravings are sharpened by what we read, see and hear, through encounters with other riders and hours spent with our noses in magazines and social media. Then comes the time to try all of this out and make our own whatever grabs us. At first, we mostly travelled on the road. The pleasure of feeling self-sufficient, far from landscapes reshaped by humans, of tracing our own path rather than following a well-marked one, keeps drawing us further away from where we started.<\/em><\/p>\n

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As craftsmen, our cravings are driven by whatever challenges us and pushes us to find solutions. Off-road bikepacking is clearly one of those subjects. The specifications of the CDM21 were therefore a ready-made playground where to experiment with new ideas for a practice still in full emergence, or at least in perpetual evolution. And then, this competition was an opportunity to build us a new machine that fits perfectly into the evolution of our practice.<\/em><\/p>\n

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We offer you here a summary of the technical file submitted to the jury of the Concours de Machine. Happy reading everyone!<\/i><\/p>\n

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Silvin and Thomas \/\/ Crank<\/i><\/p>\n<\/blockquote>\n<\/div>\n

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THE DESIGN OF OUR MACHINE<\/h2>\n

Beyond meeting the specifications proposed by the CDM21, our machine must bring us the most pleasure and fun possible on any mountain bike route that is offered to us, whether loaded or empty, and must offer a design which marks the spirits.<\/p>\n

When empty, we want a playful and fluid bike in the singles, filtering and stable in direction on the brittle zones, light and capable of gaining height. We are not yet great mountain bike technicians, and are therefore looking for a bike that is not too demanding on the trajectories and the crossings.
Loaded, we want the bike to keep as much as possible the behavior it presents when empty. The load must therefore be able to spread over the whole of the bike and move as little as possible when the bike is under load. Basically, the load must be forgotten, while allowing segmented, waterproof, quickly accessible storage.<\/p>\n

_Design<\/h3>\n

The pioneers of a practice very often leave an imperishable mark. Mountain biking is one of those practices born on the American West Coast, with a group of friends who start by dismantling and reassembling the bikes lying around in the garage, push the thinking, end up brazing their own frames after having broken too many, until you reach the first \"Mountain Bike\". Gary Fischer, Joe Breeze, Craig Mitchel or even Tom Ritchey to name a few, are among those pioneers who have pushed experimentation far enough to invent a new kind of bicycle, a new practice, and even start a trend in which big brands like Specialized get on board very quickly.<\/p>\n

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From left to right: Tom Ritchey, Joe Breeze, Charlie Kelly and Gary Fisher Source: mbaction.com<\/div>\n<\/div><\/div>
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Originally, the bikes called \u201cklunker\u201d remain the first bikes to test the rough terrain of the Santa Monica mountains. The frames, atypical in particular by their double top tube, are at the origin of cruisers more made for strolling in style on the beach. But once stripped, reassembled with the derailleur of a road bike, the brakes and levers of a motorcycle, the cruiser becomes klunker and the story begins.<\/p>\n

Our proposal for the CDM21 is our first achievement oriented towards mountain biking. Our own genesis therefore, which we wanted to include in this famous historical genesis of the \"Mountain Bike\".<\/p>\n

The design is therefore a reappropriation of the klunker style. The second top tube (made up of two 14mm diameter tubes) extends into fluid seatstays. It brings rigidity to the front triangle for precise steering, and adds length and freedom to the seatays for a flexible rear triangle.<\/p>\n<\/div>\n

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Our machine is completely rigid. We did not want to integrate suspension to experiment without filter our first mountain bike frame, and also to limit possible mechanical problems on the bike. The fork has however been designed with a significant length in order to be able to install a fork with 100mm travel without modifying the geometry. The 46 socket is ready to receive current suspension fork standards.<\/p>\n

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_Geometry<\/h3>\n

The geometry is inspired by several hardtail or full rigid references, in particular by the work of Adam Sklar and Cameron Falconer. The main idea is to mix a rear triangle close to what we do on our gravel type frames, to work on a long front triangle allowing you to play with a short stem, and to place a pronounced caster angle to filter the trajectory and erase our technical imperfections in mountain biking (67\u00b0 for the steering tube, for a trail of 102.8mm).<\/p>\n

The frame is of course generously slopping to give the rider great freedom of movement. It is built around 27.5'' wheels with a 2.4 fit, a choice once again linked to our technical level in mountain biking. The outer diameter will be easier to relaunch and carry than with 29'', and the solution of mixing 27.5 rear wheel and 29'' front wheel has been ruled out. The 29'' will be revisited when we have more practice behind us.<\/p>\n

The fork is designed around an AtoC of 460, similar to the AtoC of a 100mm travel fork. This will allow us to juggle between an all-rigid assembly and a hardtail assembly. The assembly is presented in its rigid version (see intro) for this Machine Competition.<\/p>\n<\/div>\n

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The choice of tubes remains quite classic. A mix of Life (D28.6 top tube), Zona (chainstays, D31.7 seat tube, D42 down tube, D46 head tube) and 25CD4 constant thickness for the seatstays. The legs are, as on all our productions, in-house machining. The case is LOW 73mm, the rear center distance in boost 148mm.<\/p>\n

Great attention is paid to the level of the cockpit. This indeed seems to us to be a very interesting point to deal with on a mountain bike roaming perspective likely to include both technical sections and more or less long rolling sections. We therefore decided to develop and produce a bespoke handlebar for our machine. The idea is therefore to be able to provide two positions to the pilot. A longer and closer one for rolling sections. And a second more compact and with a very wide grip for technical portions. The result is a handlebar made of 7075 steel using the Alsatian company StarBar, with the following dimensions: backsweep of 20\u00b0, uprise of 62mm, upsweep of 40\u00b0, upper width of 780mm and lower width of 370mm.<\/p>\n

Note that following the requests received since the competition, that we are thinking about launching mini-series of this hanger. Do not hesitate to contact us if you are also interested!<\/p>\n

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Coupled with a 100mm stem, it becomes a super versatile handlebar. The furthest position really allows you to approach a position similar to what extensions could bring. And the 40\u00b0 upsweep coupled with the 20\u00b0 backsweep allows the upper part of the handlebar to offer a perfect position for technical portions (virtual stem length of 30mm). We were able to test this new design several times before the CDM and found it very relevant.<\/p>\n<\/div>\n<\/div><\/div>

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LUGGAGE<\/h3>\n

Given the specifications, it was very natural to work on a tailor-made luggage set. We submitted the idea of collaboration to Wizard Works<\/a><\/strong> , a craft brand based in London with whom we had wanted to work for a while.<\/p>\n

The reflection first focused on the definition of the location of the luggage storage, with a certain volume to be reached, namely about 50 liters compared to the specifications and our habits concerning equipment while traveling. The frame itself is operated with two framebags, two equivalent bags are provided at the rear of the saddle and on the handlebars, a top tube bag and two stem bags complete the set.<\/p>\n

The content is then distributed between the different volumes to verify that the configuration is consistent.<\/p>\n<\/div>\n<\/div><\/div>

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The luggage is made by Wizard Works in olive X-pack and purple Cordura. The interior lining is done in yellow for easy viewing of content. The framebags and the top tube bag are screwed directly to the frame using M5 eyelets provided for this purpose.<\/p>\n<\/div>\n<\/div><\/div>

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LUGGAGE RACK<\/h3>\n

The racks were defined in parallel with the luggage storage. The framebags being directly screwed on the frame, it remained to design the racks for the front and rear panniers.<\/p>\n

_In the front<\/h4>\n

A rack+shifter configuration is retained. The rack is fixed exclusively on the crown of the fork to limit the length of tube used. The pack holder is also used to offset the lamp to the front of the bag. The shifter allows him not to clutter the hanger to leave the central part accessible for the hands. The whole is only 200gr.<\/p>\n<\/div>\n<\/div><\/div>

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_In back<\/h4>\n

The rear triangle has been designed to work in elasticity. The rear rack must therefore not rest on this triangle. The Carradice-type solution does not suit us for committed riding for two reasons: the design of the Caradice support remains quite fragile for off-road use, and the location of the bag just behind the saddle prevents the rider from stepping back behind the saddle. To overcome these limits, we have designed a rack that is installed directly on the seat post. The support is designed with a generous downward and rear offset to free up the rider's rearward movements, and the two support points on the seatpost allow the support to be triangulated. The free space left at the level of the triangulation allows the storage of spare shoes during trips (sandals\/car shoes).<\/p>\n<\/div><\/div>

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THE FINAL CUT<\/h3>\n

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_List of components<\/h4>\n

The assembly is quite classic, with a single-chainring 32T drivetrain and 11 rear gears (11-46). a hub dynamo assembly powering the front and rear headlights. The Honcho 27.5''x2.4 tire from Teravail has been selected for its very effective grip while keeping a good ability to roll on the flat without too much noise pollution thanks to the close reliefs in the center of the profile. Cable disc braking is preferred over disc braking for ease of maintenance for a very long trip.<\/p>\n

To stay in the world of pioneers (in particular), we wanted to make an assembly that remained accessible in terms of budget.<\/p>\n

Crankset: Specialty TA Arrow 32t \/\/ Cassette: Shimano XT 11-46 \/\/ Disc brake caliper: TRP Spyke \/\/ Discs: Sram 160mm \/\/ Levers: Shimano Deore XT \/\/ Rear derailleur: Shimano Deore XT \/\/ Stem: Custom crank \/\/ Seat post: Thomson Elite \/\/ Handlebar: Custom crank \/\/ Headset: HOPE \/\/ Rear wheel: DT Swiss & 350 classic \/\/ Front wheel: DT Swiss & Shutter Precision Dynamo \/\/ Tires: Teravail Honcho 27.5'' x 2.4 \/\/ Lighting: Busch & M\u00fcller IQ-X + Line small \/\/ Saddle: Berthoud Aspin \/\/ Grip: ESI Chunky<\/p>\n<\/div><\/div>

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OUR RESPONSES TO THE CDC<\/h3>\n

Overall, all points of the CDM21 specifications were addressed during the design of the bike, except for the constraint of being quickly compactable. We had dealt with this point in depth during the CDM2019 and did not wish to revisit it this year, for the main reason that we are used to using transport covers in the train and that no specific system does not is necessary on our machine to store it in a cover to the dimensions of the sncf. And as we particularly like station platforms, this year we will not be looking to save a few minutes on packing our bikes.<\/p>\n

Let's review a few points of the specifications to which we appreciated responding:<\/p>\n

_Waste management: We are very sensitive to zero waste. And it's a consumption habit that's harder to stick to on a bike trip than in everyday life. Most of the waste during a trip is that resulting from our meals, and it is therefore on the way we eat that the answer to this question is based. We carry different dry materials (oat flakes, semolina, pasta, pulses, dried fruits) in cloth bags or reused paper bags. We are also planning a few extra bags so that we can use them during the shopping on the way. We also learn about picking (what to pick and how to pick well) to feed the preparations during the bivouac with the herbs and spices found on the way.
The waste that we can still produce during the trip is sorted in the two side pockets of the rear bag and then thrown away when sorting bins are encountered. And when we travel to areas with hostels\/restaurants etc., having a meal there is another solution to avoid unnecessary packing.<\/p>\n

_Keep a trace of this experience: We are used to documenting our trips with photos. On this machine, our camera (Fuji XT2+Pancake 27mm) is transported in the right stem bag. Access is therefore quick and even allows you to shoot while driving.<\/p>\n

_Electric autonomy: A powerbank of 22000mAh (+a bonus of 10000mAh) are carried in the bag of top tube and allow to last 5 days in electric autonomy according to our experience (telephone + gps). During a trip, our phone is used for the possible management of the route and the export to the gps, for contact with the outside world if necessary, for the weather, and to share on the networks if we want says.<\/p>\n

_Additional functionality: We were keen to work on the aesthetics of the bike, and it was an opportunity for us to look at the history behind the emergence of mountain biking. We also wanted this bike to be available as a high-performance hardtail to be able to develop and perfect our practice of mountain biking on day trips.<\/p>\n

_Carrying: A space has been left free at the back of the upper framebag for carrying areas.<\/p>\n<\/div><\/div>

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THE MACHINE ON A TRAVEL<\/h4>\n

Our CDM21 proposal has already had several opportunities to be tested in real conditions, since it has been installed since February 2021. The last of them, an expedition in the footsteps of the French Divide between Clermont-Ferrand and Puycelsi in 3 days. The fully loaded configuration, with all the equipment requested by the cdc and necessary for quality bivouacs, passed without incident and allowed us to take a lot of pleasure on this beautiful route (~150km\/2800D+ per day). Note that it was quite special to develop a competition bike over so long, compared to our past experience on the CDM19. If the frame kit has remained very close to the first drawings made more than a year ago, the rest of the project has had time to mature, several rack configurations have in particular been tested, and this year we present to you a successful machine of which we are very proud!<\/p>\n

Find all the images of our bike from the Concours de Machines 2021 here!<\/a><\/strong><\/p>\n

Our build has also appeared on The Radavist<\/a><\/strong> and Bikepacking.com<\/a><\/strong><\/p>\n<\/div><\/div><\/div><\/div>

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