Talking about monocoque

The term monocoque never goes out of style. It has even been called into question by Elon Musk during Tesla's Cybertruck presentation and is now widely used in many industries. The term monocoque comes from the French, literally "single shell" and was originally introduced in the field of boats [1-3], then transferred to the first airplanes to finally land in the automotive world thanks to André Gustave Citroën [4,5]. In general, in any closed vehicle, a monocoque is a structural shell capable of responding to external loads through stresses that are generated on the external skin without the need for a chassis for this function. The more the shell is closed and made up of a single part (mono), the more effective it will be in its structural function, just as it happens for an egg shell (coque), so fragile as to shatter between the fingers once broken, but so resistant as to require a decisive blow to break it as long as it is intact. Over time, the term monocoque was then "watered down" and revisited in a thousand keys of interpretation, sometimes called out in vain, generating not a little confusion and lending itself to some marketing tricks, as in the case of cycling.

Declined in the world of carbon fiber cycling frames, the term monocoque inevitably loses its link with the word “body”, since the racing bicycle is certainly not a closed vehicle. If you think about it, the same expression “monocoque frame” would be an oxymoron if it referred to a “shell that does not require an internal frame”: how could a frame exist that does not need a frame? Eventually, remaining in the pedal galaxy, the original meaning of monocoque could apply to some constructive solutions for fairing recumbent bicycles, the so-called streamliners, which having an external shell with aerodynamic function, can be designed in such a way as to give this also structural tasks. The same universe as human-powered vehicles in which the bicycle also falls, the same galaxy of pedals and leg muscles, but another solar system compared to the traditional bike.

Returning to this planet, in the cycling industry the term monocoque takes on a very different connotation and indicates a manufacturing process that takes place “in one piece” through the use of a mold. Also here, as well explained in [6-8], there are at least a couple of nuances: integral monocoque “rear frame included” (rare) or referring to the main triangle only (more common), but in both cases the common denominator is the “one-piece” construction process by means of a mold, which excludes the use of pre-formed tubes which are joined in a second process phase by gluing, wrapping or co-molding.

What changes? More than you imagine. The design and the shape first, that are severely limited when using preformed tubes to be cut. And then the layering of prepregs done on a single mold offers optimization chances that fade out when finished pipes must be joined. The downside is that, at least to date, the use of a mold prevents the construction of tailored frames that are truly monocoque: for custom size, preformed tubes are still needed to be cutted and joined in subsequent steps. The joining process can be more or less evolved from a technological point of view, it can take place by involving molds again and result in a pleasant and structurally effective product to the point of looking like a monocoque to the inexperienced eye, but between “looking like” and “being” there’s still a clear line of demarcation.

Why is Gregario talking to you about monocoque? We will tell you about it in one of the next episodes, stay tuned and when you come across someone who wants to sell you a monocoque frame, sharpen your eyes… if you really don’t know how to find and understand his patents, look at the construction details and photos of the process it divulges: in short, keep an eye on preformed pipes and co-molding, which certainly offer their advantages and are not technologies to snub at all, but it is correct to expect that they are not passed off as monocoque.

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Blog | 29 March 2024

Handmade

At Gregario, we have always cultivated esteem and respect for the artisanal frame-building tradition of our beautiful country, which is dedicated to a niche of timeless “classic” products, primarily made from steel, but also incorporating wrapped carbon and other techniques specific to small workshops.

So long live frame builders and anyone dedicated to preservation and pass on a noble and fascinating ars technica !

That said, we recently came across some social media posts from several respected bicycle craftspeople who, while rightly praising the (undoubted) qualities of their frames, contrast their “handmade” products with “moulded” monocoque carbon frames. On the face of it, this seems like a legitimate claim, but this narrative leads to significant misinformation about HOW such “moulded” frames are actually produced… namely, with manual work that is decidedly more demanding and onerous than any technique for joining eight tubes.

Yes, because we are not talking about printing cookies, but rather about carefully arranging over 200 fabric shapes (pre-impregnated carbon) inside a mould. These pieces range from 40 cm strips to tiny stamps, all positioned by hand according to a precise plan (the ply-book) with meticulous overlaps, folds to manage and fibre orientations to respect. And this is only half the work, because then, depending on the resin curing technology used, there are a further series of steps involved, always rigorously by hand.

In the case of autoclaves (the most common technique in Europe), it is necessary to carefully position the internal bags, close the two half-moulds without pinching anything, arrange a series of auxiliary materials, close the external bag, apply the putty to connect the internal bags with the external and so on until the whole thing is cured under high pressure and temperature. Furthermore, once the curing is finished, it’s back to manual work for mould opening, part extraction, and finishing. All this with a series of possible variations we won’t go into now.

In short, there is nothing more “handmade” than a carbon monocoque frame.

Blog | 11 August 2023

Cycling meditating

Every successful ride is first and foremost a meditation activity.

Sooner or later along the way, we find ourselves entering a sort of trance: the lungs ventilate, the heart pumps, the muscle memory becomes automatic pilot: intensity, timing, coordination, reflexes. At this point, the brain has “only” to keep an eye on potholes and other road users (and that’s no small thing), but, considering the available computing power, it finds itself unemployed on average. Daily problems are suddenly summoned to a quick and decisive mental meeting: what can be solved is solved, what is not important is reduced, a sudden “lateral” gaze opens up on what seemed insoluble. The shower upon return consolidates the thoughts, fixes the fundamental ideas and we are ready to face new personal and professional challenges.

However, all this happens only on one condition: the absence of pain. Fatigue isn’t a problem, that’s part of the game, it’s wanted and desired by the cyclist, but pain is a whole other story, pain ruins everything. A knee that becomes inflamed, an insistent discomfort in the neck or an unexpected burning in the groin can compromise all the meditative pleasure. The brain can’t focus on anything else: “Maybe if I go back a little on the saddle… no, now I’ll try standing up… nothing to do, I’ll go back to gripping high… nothing, maybe a sprint will help to unlock, nope… what do I do? I know I have to go back.” Missed goals and consequent disappointment.

Then, maybe, you wait a few days, even a week and try again. And what a frustration when that pain makes itself felt again, perhaps even after a few kms in which it has left us harboring the illusion of a successful ride. Even in the hypothesis of lowering the pace and concluding the following rides without problems, the mental state is compromised: one spends the time listening to the nerves, registering every slightest signal, in fear of recognizing the beginning of that pain again.

In the worst case, you enter a loop of medical visits, bike-fitting sessions, saddle/handlebar/stem/riser/cleat/adjustment changes/etc. And in all of this we stop at a certain point to think: where is that pleasure of getting on our most faithful bike, taking the road and quickly entering that meditation bubble?

Anyone who has known this path knows that a custom frame represents the most effective and long-lasting solution. A custom frame is designed to adapt to the physical and morphological characteristics of the cyclist, ensuring optimal posture, balanced weight distribution and less pressure on the joints. Thanks to this customization, the risk of experiencing pain and injuries is drastically reduced, allowing you to fully enjoy every pedal stroke and to keep your mind focused on the essence of the journey. Investing in a custom frame is investing in your physical and mental well-being, rediscovering that meditation in motion that makes cycling one of the most rewarding and liberating experiences. Only in this way will the cyclist be able to rediscover the true meaning of that meditation bubble on two wheels, where the body, the mind and the road merge in perfect harmony.

Blog | 19 June 2023