Many brands are customer lead which is not always a good idea in industries such as automotive, aviation motorcycling and cycling. In aviation there is a very robust safety and procedure culture in place which is engineer lead. Cycling was largely unregulated if it were not for organisations such as the UCI who’s prime function is to ensure fair play and ensure the tools of competition are fit for purpose. This organisation has a huge affect on all manufactured cycling product both directly and indirectly. In fact non-UCI competition see all kinds of interesting craft in Iron-man. This ‘open-forum’ is the breeding ground for future designs which also indirectly puts pressure on the UCI for example weight restrictions of 6.8kg at the time of writing.

If you imagine a Specialized Aethos frame weighting in a just over 600g it is no wonder there is so much criticism toward the UCI’s seemingly backward approach to introducing more current specs into the completion but maybe they know something we don’t appreciate. For example the 6.8kg weight restriction (build bike) was introduced in 2000. I can attest to the fact that todays carbon bikes do not look even vaguely the same nor are they manufactured in the same way.

Tests back in 2000 showed the UCI officials that 6.8kg was the minimum weight the frames could be deemed safe from structural collapse. If you think that in those days all carbon bikes were hand bonded carbon frames. Bottom brackets were woefully thin as were the chain sets causing these frames to be very flexible and heavy in comparison to the aluminium predecessors.

Manufacture processes have improved as brands understand what has gone wrong in the past. For example you will see very few alloy and carbon components mated and bonded together. These two materials are incompatible with each other as the alloy expands and contracts at a different rate to carbon which is a lot more stable. The epoxies used simply failed over time. Warranties covered joints where frame sets were bonded together by hand to make a ‘ monocoque’ frame when in actual practice only now are we seeing true monocoques appear. The difference is notable in that these true ‘monocoques’ are connected together by carbon laminate and not as sections held together by epoxy. We as repairers see 70% less mid tube manufacture failures compared with the past so these modern warranties reflect this improvement.

With the advent of disk wheels we can now see the challenges of awful rim brake concepts being thrown out in favour of non wearing rims or alloy/ carbon wheels. The other improvement in carbon bikes are the through axil systems as opposed to quick release dropouts which was a hangover from pure alloy bikes. Alloy being the best material for this system but a disaster for carbon.

Most of these modifications are largely borne out of the cost of warranty replacements but not in the name of progress.

So what is not so good about modern bikes then? I equate most my criticism to design memory. Bike companies are renowned for lower pay design jobs and/or a stepping stone to bigger things. This has an affect on the legacy of good designs and the reasons they were implemented in the first place. When new designers make their mark I believe this is where some good ideas are not re-considered because they are ‘old.’

Lets look at a not so obvious example – The rear seat stay position on the seat tube. The ‘old’ style was to junction the top of the stays at the same height as the top tube junction with the seat post clamp. It is obvious to me that this traditional geometry allowed the seat tube to flex and pivot at this junction providing much needed relieve and even a form of suspension. But because TT bikes, in particular, look ‘racey’ because the geometry of the stays are low down for aero reasons the simply assume that we can sell more aero road bikes which look this way when in fact we are applying designs to a different discipline with little to no regard for the different conditions in which the road bike operates.

Some brands looked really hard at this fatigue issue as an advance by introducing flexible junctions while other brands simply ignored this, in fact, locking off any flexibility by lowering the seat stays and extending them into the top tube to boot! Now I cannot claim to be a successful bike designer but I can say this: As a multi brand repairer who mainly specialises in bikes which have already been produced, it is astonishing to me how we are still seeing such fundamental errors not seen in aerospace or automotive industries.

That said I believe the level of manufacturing skill in carbon bikes as far and material application and processing is far advanced compared with other industries such as F1 even. I have seen both and my view remains unwavering. If we could enlist the pro-cyclist team leader with an F1 engineer in design with the skills of a bike manufacturing engineer then we would most likely set a standard to beat for a long time but sadly this is not the motivation for the bike brands. They need to shift stock as best they know how. By changing and re-inventing good and bad ideas keeps the industry moving but ‘forward’ maybe not so much.

What do I think modern bikes are better at?

BB stiffness. Dialled in construction methods and weight reduction in bikes which specialise in climbing.

What do I not like about modern carbon bikes?

Ultra light weight bikes. Other that for hill climbing they do not have a comfortable function in the other 2 elevations. They are more ‘throw-away’ in longevity yet the price tags are higher than ever. Appalling after care service for high end road bikes. The inappropriate application of carbon in bike components better suited to other materials such as fork steerers.

What do I like about older carbon bikes?

Reasonable frame weight and robustness in the mid tube sections. Geometric traditions determine the best positions over time. We have not evolved as humans.

Against?

Poor understanding of carbon fibre and bikes. Inefficient understanding of bonding incompatible materials together. Caught up in the legacy of alloy bikes particularly interfaces such as dropouts, clincher wheels and rim brake systems.

So what does the future look like?

Well it seems to look a bit depressing if I am honest. As if the industry is not already legislated to comply with the ever stringent green agenda you are going to find a slight backward progression in the construction results of carbon bikes as I see the tech today. What do I mean? Well its all about recycling at the end of the day. Apparently thermoset (chemical setting carbon laminate) is not environmentally friendly. Thermoset (heat setting) is. The issue I have with thermoplastic is that it requires a lot more actual energy and material to produce a comparable carbon bike and then we are still not sure how you can recycle a spent bicycle in any useful way. Both can be ground to powder and reused using both thermoset and thermo plastic into by products such as components for bikes and other things.

To assume thermoplastic is more environmentally friendly is not the case but lets see. Some companies are embracing 3d robotic printing of rather interesting frames sets which are not restricted by traditional mould processes so we wait and see but my opinion is that there is no better marriage between carbon fibre and bicycles in any product range I can think of both in weight structural rigidity and cost.

Let us not forget that if we are talking about the environment then carbon bikes are infinitely repairable too!

‘Fortune favours the brave’

If you are not familiar with Carbon Bike Repair, we are the largest inspection, repair and restoration service with 12 years and 16,000 bikes restored in the UK and 6 years in South Africa producing a combined output of over 20,000 bikes of almost every brand and discipline produced. We have 90% all major brand endorsement with dealership support where ever we operate.

So it is a privilege to be approached by notable bike companies to review their carbon creations. Our reputation and experience of frame failures and paint provide real value with respect to the development of new bikes and most importantly committed cost and customer value.

For example when a bike is manufactured batches are tested to meet certain performance and structural criteria which must meet specific warranty terms. This is not to exclude the graphic and paint processes which must withstand 2 years of exposure under warranty.

However not all tests can simulate the real world. Time and exposure also play a role in the success of a particular bicycle. Certain external criteria such as varying rider physiology, environmental challenges and competency play a large part in the success or failure of a bike in the market place. This cannot be simulated as we see all too clearly every day. It is easy to see mistakes in hindsight.

Therefore we advise on glaring and not-so-obvious potential structural failures as well as performance and maintenance improvements. Another important benefit is batch testing to ensure problematic bikes are identified for reasons only identified by design tweaking and poor governance at the factories.

As mentioned previously, a large part of our evaluation process includes application techniques on finishes and special effects such as candy, metallic, flip paints, matt or heat application decals and foil based decals. This can be a very real issue for the brands. We assist in finding practical solutions from our experience as bike restorers.

So it is fantastic that Carbon Bike Repair’s exposure to many good and bad ideas are being recognised as valuable support and not criticism.

Swiss based bike brand is entering the market

When SWI met with CBR they understood quickly what we could offer them. The designer himself flew over to ensure, before any assessments were performed, that we understood their aim. For us this is fundamental in aligning ourselves with the vision of the brand.

SWI made claims to be the first true monocoque out of a mould in one piece. That might sound like an odd pronouncement considering the term ‘monocoque’ has been a brand phrase for many years when in fact they are bonded lugged bikes.

Why is a true monocoque an advantage?

Because of the structural stiffness of a pure unbroken carbon thread construction from back to front. Simply put, this achieves a notable increase in stiffness relative to mass as well as a more visceral and connected sense of performance. A true monocoque also limits the potential of epoxy bonded lug failures which are warrantable in many cases.

The process of evaluation includes a high definition scan to ensure consistency of alignment and potential mould warpage minimisations. The frame set is physically dissected to review wall thickness optimisation, composite compression conditions in the mid sections as well as in the compressed areas around seat clamps and fork steerer crowns in particular.

As a result we made significant observations to improve the SWI bike. This included amplifying performance opportunities by changing some of the DNA of the construction. I look forward to the ISO tests in Germany to see if indeed SWI is able to receive the green light for production of this impressive Monocoque bicycle.

Please contact Carbon Bike Repair to discuss similar reviews of conceptual and current carbon product.

Founded on the principle of extending the lifespan of carbon bikes through expert repair and refurbishment, Carbon Bike Repairs has revolutionised the cycling industry. This case study looks into their innovative approaches, strategic decisions, and the impact it has made on both cyclists and the environment.

In the world of cycling, carbon fibre has emerged as the material of choice for its unmatched strength-to-weight ratio and aerodynamic properties.

From developing proprietary repair techniques to fostering partnerships with leading bike manufacturers, Carbon Bike Repairs has navigated the complex landscape of carbon fibre repair. Through meticulous attention to detail and a commitment to quality, the company has earned the trust of cyclists worldwide, establishing itself as a beacon of reliability in an industry characterised by constant innovation.

Challenge

Repairing carbon fibre bike frames presents unique challenges due to the complex structure of the material and the need for the utmost precision, it also requires meticulous attention to detail, especially in maintaining the frame’s structural integrity and original geometry.

Traditional repair methods often struggle to achieve the level of precision required for optimal performance and
safety, which is why Carbon Bike Repairs looked to find an alternative solution for their repair process and adopted
3D Scanning technology as an integral part of it to ensure increased accuracy and quality of repairs.

Vision

Carbon Bike Repair envisioned a solution that would streamline their repair processes, enhance accuracy, and ultimately deliver superior-quality repairs to their customers. They aimed to integrate cutting-edge technology that could optimise their workflow and ensure consistent, high-quality outcomes setting a new standard in carbon fibre frame repair, providing cyclists with durable and reliable solutions.

Application

The Creaform HandySCAN Silver was introduced into Carbon Bike Repair’s workflow to revolutionise their repair processes. This advanced 3D scanning technology allows for precise measurements and comprehensive inspections of damaged bike frames, enabling technicians to identify even the smallest imperfections.

Carbon Bike Repair utilises a unique re-construction process for their frame repairs, setting them apart from traditional repair shops. Unlike the majority of carbon frames that are repaired without the bikes specifications, CBR’s frames are reconstituted by replicating the exact mould to deliver an x-ray invisible restoration with a lifetime warranty that is valid

The Repair Process

The repair process at Carbon Bike Repair begins with scanning two frame sets using the Creaform HandySCAN Silver. This allows for accurate measurement and comparison of geometry between frames.

The HandySCAN Silver provides detailed data, ensuring precise replication of the original frame geometry

Benefits

Precision: The HandySCAN Silver provides precise 3D measurements, allowing technicians to assess damage and execute repairs with unparalleled accuracy.

Efficiency: By streamlining the repair process, the HandySCAN Silver reduces turnaround times, enabling Carbon Bike Repair to deliver repairs to customers faster.

Quality: The use of advanced technology guarantees the highest standard of repair, enhancing the durability and safety of repaired frames.

Versatility: The portability and versatility of the HandySCAN Silver allow technicians to perform scans in various

environments, making it an invaluable tool in the repair workshop.

Innovation: Carbon Bike Repair’s adoption of the HandySCAN Silver demonstrates its commitment to innovation and excellence within its industry

The Final Outcome

With the integration of the Creaform HandySCAN Silver into their processes, Carbon Bike Repair has achieved remarkable improvements in efficiency, accuracy, and quality. Their ability to deliver superior repairs to customers has strengthened their position as a leader in the industry, while also enhancing customer satisfaction and loyalty.

Writers Credit: Leigh Edwards from MSL 3D Scanning

The views expressed here are mine alone. They do not reflect bikes in development or the general consensus in the cycling community but it is high time someone who repairs them for a living should speak up !

So let’s now look then at the job a carbon bike actually has to do:

Terrain – Are ultra-lights frames really gaining the overall advantage?
The 3 main elevations are flat, down and up right? I would argue the point that for the most part a heavier bike would be more suitable for 2 of the 3 elevations. Head winds and downhill control are better suited by heavier frames. Yes of course an ultra-light frame is a key component of climbing but really only at pro level I am afraid. Modern carbon bikes with frames sets weighing 1kg or more with a good group set and suitable ratios and geometry are more than capable over all terrain.

Road surface – Ultra-light frames are affected far more by our very poor quality roads. Fatigue through vibration, and structural failure from close encounters with potholes affect ultra-light frames more easily than is the case with heavier frames.

Elements – Rider weight unless you are an under nourished pro can vary greatly overtime yet ultra-light frames are designed only to handle specific weight limits, flex tolerances / distribution and, impact through the wheels. At any one moment at least the first 2 of these elements are in play constantly, add anymore and you go into, what I call, the ‘red zone’.

The ‘red-zone’ is where designers have not purposely build in sufficient redundancy guarantees, and where a trade-off between the ultra-light weight advantages and the above variables co-exist ! You can only hope the designers of your particular frame have been generous in the red zone. A general rule of thumb – the lighter the frame the smaller the ‘red-zone’.

Turbo trainers! For ultra-light frames it is critical what type you use. The purpose of ultra-lite frames is to be stiff and light. These frame sets are not designed to flex at 1 mount point, well no carbon bike really is but more so on ultra-lights. You are better off on rollers or where the trainer unit can flex rather than the frame. We have received enough frame sets to realise that there is a link.

Brand competence

When it comes to light weight bikes there are some brands who are not qualified to produce these bikes. A general trend we see is smaller brands copying the bigger brands but without the data. My advice is ONLY consider major brands for ultra-lights, TT or sprint bikes. They have the most impressive facilities to entertain such ideas but even they are not immune from the marketing pressures which afflict most brands. The good news is that more moderate carbon bikes and even the many Chinese brands selling in the west now are generally very good value indeed! Watch Jourdain Coleman’s YouTube channel on this

So why are we seeing this seemingly irresponsible behaviour by the brands?

If we break it down, one of the key factors is compliance with the UCI regulations for their pro team sponsored bikes which, for those who are not aware, require only retail available components to be used. Having this level of endorsement opportunity shows brand competence participation, none of which serve the amateur cyclist in my opinion. There should be a UCI pro- race bike category which is totally separate from commercial high end bikes. There should be a clear mandate to qualify in order to attain one. This would keep competition in the pro and amateur events fair but most importantly would stop the un-informed from being able to acquire such specific frame sets. In other words ‘fit for purpose’.

The big concern should be when these ultra-light bikes are sold on. Who is qualified to inspect these frames, what controls and guidelines are retained to ensure the cyclist is fully informed of the weight limits set for the bike? Our unregulated cycling market place is a far cry from the pro team structure. The pro-team rider has a support structure to ensure diet, good training and a technical team to realise the full potential of the bike, then discarded when appropriate.

I think we are playing with fire if we continue to go lighter. Ancillary component choice and setup is more fundamental to ensure you are actually getting the most out of your frameset without risking your safety. It is crazy to think that the trend is to buy the lightest frameset you can afford with heavy disk brakes and 2 water bottles. Always the frame first.

How do we know all this?

Carbon Bike Repair have been leading the carbon repair and restoration industry for 12 years we have completed over 16,000 repairs, we have a lot to offer from all this experience. CBR has been recognised at brand level to advise on prototypes and assist with suggested structural modifications on some existing models.

Ultra-light frames have some wall thicknesses of around 0.4 mm, so we have purposely invested and pioneered the use of robotic repairs giving us an accuracy tolerance of 0.02 mm affording us the very best results for the repairing of ultra-light frames.

I have been wanting to write this article for some weeks now because of some alarming findings during an experimental project to remove weight from an average weight, mainstream brand frame; let me explain:

The robot was instructed to remove only 0.1mm of material from the top and down tubes as a test. There simply was no other safe or large enough location to make a difference. The robot completed the top tube and the firmness was still the same however not so for the downtube. At 0.1mm the robot opened about 4 holes at the base of the downtube running along the seam line toward the bottom bracket causing us confusion. We initially assumed the robot had made an error but when we rechecked the data we noted that this area was less than 0.1mm thick in places and yet this frame had been successfully ridden in National Competition.

So how was this possible without it failing?

The rider was very light, with good technique in managing high watt output, yet clearly the frame was able to cope with this very obvious but specific use.

You get where I am going with this?

You may argue that this model posed no problems but I would ask you how do you feel about your ultra-light frame being clamped or fitted to a roof rack, transported in a flight case or hitting a pot hole or crashing in a race. How long will it last?

But more importantly ask yourself if you really need a 200g saving from the frame would it not be better to use lighter components or indeed to lose the weight from yourself !

If you would like to hear my comments on carbon wheels please drop me a line at info@carbonbikerepair.co.uk

Carbon fiber is often considered a superior material for bicycle frames because it is strong, light, and relatively easily fabricated to be super stiff in one direction yet compliant in another. Despite its popularity, it’s not a material that’s well understood. Why is it so expensive? Why was it invented? Is it repairable? Will it wreck the planet? Let’s find out.

Why Carbon Fibre?

Carbon fiber is a versatile composite that enables bike designers to develop frames with qualities specifically suited to particular applications. They can be brilliant on tarmac, plush off-road or rocket fast on the track. Bikes can be developed to be predominately stiff and racy – my Specialized Venge aero bike feels so rigid it barely flexes at all – or swift but comfortable, like the beautiful Bianchi Specialissima, a performance endurance bike that can be ridden for days.

Because carbon fiber fabrication – commonly known as layup – doesn’t require unsightly joins, frames can take on attractive, organic shapes too, often in the quest for aero gains. It’s the sort of material that makes people coo.

Why the high cost?

There’s no getting away from it, even entry-level carbon frames are expensive. A premium carbon fiber bike, such as a Trek Madone SLR 9 Gen 7, can set you back more than $16,000/£13,000, with at least a third of that cost attributable to the frame. Why the weighty price tag?

“Fifteen years ago, the cost of building a frame was a third labour, a third materials, and a third overheads, but now labour has become the highest expense,” says Rob Gitelis, CEO of Factor Bikes. “A lot of companies have moved factories from China to Southeast Asia because they’re looking for lower cost labour.”

The cost of materials has shot up too. Carbon fiber is made from oil, so its price has been increasing amid the recent Middle East tensions and Red Sea shipping attacks.

“If we look at 2023 to 2024, there’s been about a 16% increase in the price of carbon fiber,” says Gitelis. “Oil is definitely a really big factor, as is demand from other industries. A lot of the time we’re competing with the aerospace industry for material, which causes the price to increase.”

Despite this, Gitelis believes it’s unlikely price increases will be passed onto the consumer just yet.

“I think a lot of the carbon fiber manufacturers will be looking for price increases, but brands will have to absorb these because business is so competitive at the moment. There’s a lot of inventory causing trouble.”

The cost of carbon also depends on which type or grade of fiber is used.

“There are a lot of different factors that go into the costs, from the price of oil, to how you design the frame, but it also depends on which fibers you’re using and how refined they are,” explains Sam Pendred, design engineer at Hope.

“For our track frames we’re using the highest spec carbon fiber – high modulus – you can get, which was expensive anyway, but is still going up. But if you use a more standard modulus fiber, it’s less.’

According to Pendred, 100g of high modulus UD (unidirectional) carbon fiber costs over £100 per square metre, while 300g standard modulus UD costs under £25. Approximately seven square metres go into a Hope track frame, of which most is 100g high mod UD, thus costing the brand about £700 in material costs.

What is carbon fibre?

Surprisingly, for what’s considered a cutting-edge material, carbon fiber was developed more than 160 years ago, originally for use in incandescent light bulbs. However, it failed to light up much excitement until the aerospace industry recognised its usefulness in the 1960s. As previously mentioned, it’s a by-product of the oil industry.

“Carbon fiber is made from the base tar from oil refineries, it’s essentially sludge,” explains Rob Granville, director of Carbon Bike Repair.

“This sludge is separated into two types of carbon: the cheap carbon, which looks like an asbestos replacement and acts like cement, and the finer stuff called Polyacrylonitrile (PAN) carbon.

“It is this carbon which is then purified, using heat, and from that process you get graphite, which is the first material you can use. From there it is heated again to get what we call low modulus carbon, which is what most bicycles are made of. If you heat it again, and add more chemicals, you get high modulus carbon, which is very strong and very stiff, but incredibly fragile.”

“During the heating process, the PAN fibers are spun out repeatedly to get rid of all the oxygen and then heated again at very high temperatures to carbonise it, getting rid of any impurities,” adds Chris Clarke, composite expert at Hope.

“What is left are fine filaments about ten times less than the width of a human hair. These filaments are grouped together into what’s known as tow, which is then wound onto a bobbin. The fibers are woven into a fabric, which is impregnated with an epoxy resin to glue them together, creating thermoset prepreg carbon fiber sheets.

“The reason we use prepreg is so we can accurately predict how much resin to fiber we get, which is important when you’re trying to predict strength and stiffness.”

How are carbon frames made?

To make a bicycle frame, sheets of prepreg carbon fiber are cut and layered on top of one another in a mould. How the sheets are laid up, both in thickness and direction, will influence the properties of the final frame, allowing stiffness, strength and compliance to be dialled in – and out – at will.

“One of the qualities of carbon fiber, which makes it so attractive to bicycle manufacturers, is that you can hide the DNA of a frame’s construction in the layup,” says Granville. “Nobody can tell how many layers are in the frame except the designer.

“Once layered up, the frame is put into a giant oven called an autoclave, where it is heated until the epoxy within the layers softens enough to bond them together. To stop the frame collapsing inward, balloon-like bladders are strategically placed within the tubes.

“From a design perspective, carbon fiber offers infinite possibilities because a frame can take on almost any form. I believe the designers within our industry are some of the finest creatives working with composites today, even more so than Formula One. Yes, the opportunities that carbon fiber offers designers are infinite but they still have to work within strict limitations – weight, power output, UCI rules and what the market will bear in terms of performance, aesthetics and cost.”

Is a repaired carbon frame safe?

Many riders are under the misapprehension that carbon fiber cannot be repaired, although it is true that repairing a carbon frame is not always straightforward.

“It amazes me after all these years that some people are unaware that carbon can be repaired,” says Granville.

“It’s correct that modern bikes are almost irreparable by hand. If you don’t have a machine that can simulate the actual mould that the bike came out of, the compression of the carbon, the wall thickness of the carbon and the profile of the frame, then you cannot guarantee the repair without cutting the bike in half to check it. It takes technology to make a bicycle and technology to repair one these days.

“Carbon fiber is infinitely reparable provided you can place carbon on carbon and they bind. Bearing in mind that you cannot test to destruction, the only things unwise to repair are parts of a frame that are both unique and structurally critical. For example, can you imagine your steerer tube snapping at the foot of your head tube? You would go face down. It’s the same with handlebars, particularly where the stem clamps.”

How sustainable is carbon fibre?

As a by-product of the oil industry, and a reliance on a manufacturing process that consumes a lot of energy, it’s challenging to consider carbon fiber a sustainable material.

“The main environmental issues with carbon fiber are the production process and the waste at the end of the product lifetime,” explains Erik Bronsvoort, founder of Circular Cycling.

“The energy requirement to make the fibers, and the associated CO2 emissions are huge. For each kg of carbon fibers produced, 20kg of CO2 are emitted. That’s before they’re mixed with resin and transformed into a product.

“The waste at the end of the lifetime is also problematic. Most thermoset carbon fiber used in bicycles cannot be recycled. It ends up in landfill, or probably even worse, is burned in an incinerator, where the resin melts or burns, but the temperature is too low to burn the fibers, which end up in the ash. This ash is then often used as a “green” product in road construction, making things even worse in the future.

“Every brand and designer needs to take responsibility for the products they bring to the market. This goes from labor rights in the supply chain, to deforestation, energy use, product longevity, repair options and waste. The impact our linear economic system has on our planet can no longer be ignored, and waiting for governments, or expecting consumers to do the right thing is just not good enough.”

So, how does Bronsvoort see the future of carbon fiber unfolding?

“As more companies become aware of the impact of carbon fiber, more will start to innovate alternatives,” says Bronsvoort.

“For example, I have seen some really cool developments in biofiber composites in the sailing and car industries. So, I think we will see more recycled biocomposites in the future, with traditional thermoset carbon fiber being reserved for the ultra-high-end parts where it’s really needed.”

Is thermoplastic a solution?

Thermoplastic carbon composite is gaining momentum as a more sustainable alternative to thermoset carbon fiber, but is this reputation deserved?

“Part of the global initiative around waste is to remove the thermoset process, because it produces materials, like carbon fiber, that can be repurposed,” explains Granville.

“As a result, the composite industry is turning to thermoplastic carbon fiber as one alternative. Thermoplastic is a standard plastic, like nylon or polypropylene, which is ground up and can be melted down several times. You pour this plastic goo onto strands of carbon, compressing and squeezing it until it is thoroughly incorporated. When it is dry and ready for manufacturing, another piece of carbon is laid on top, ready for more heat to be applied until the materials melt and bond together, resulting in a thermoplastic component.

“If, at a later date, the product gets chopped up, the material can be reused by reheating it, enabling a substantial waste reduction. The first products we’ve seen made from thermoplastic, or fusion plastics as some people call it, have been mountain bike wheels because they’re softer to ride, providing a bit of suspension. Thermoplastic is interesting, but it’s not as efficient in its stiffness as thermoset, so manufacturers are struggling to make frames as fine and as light.”

For Bronsvoort, it’s also not clear-cut.

“Thermoplastics offer the option to recover the fibers by melting away the resin, but I have not seen proof that these fibers can be used to make the same product again – usually you see a ‘downcycle’ instead of a ‘recycle’ as fibers get shorter,” says Bronsvoort.

“Another thing is, how do consumers recognise that a product is recyclable thermoplastic? How does the product end up in a facility that has the technology to recycle it? These consumer-related reverse logistics factors are difficult to overcome.”

Or is it plant based fibres?

Carbon manufacturer Toray obtained certification to use biomass to produce and supply carbon fiber from the end of 2023, but exactly what these materials contain is not clear. Toray did not respond to Cycling Weekly for a comment, so we turned to Hope’s Chris Clarke for a prediction.

“Plant-based fibers are being considered,” says Clarke. “Flax has been tried before but was difficult to make and not very strong. But there’s a material called lignin, which people think they can carbonise instead of oil in the future.

“Lignin is a polymer that fills the spaces between cellulose fibers in the cell walls of plants, making them rigid. It is found mainly in woody plants, such as shrubs and trees, and is widely abundant.”

According to research on sustainable lignin-based carbon fiber, replacing traditional carbon fiber with lignin-based carbon fiber reduces the global warming potential of production by 54%.

But not everyone is convinced.

“Almost any fabric or textile can be turned into a carbon fiber substitute material if you mix it with a resin that will cure into a solid form,” says Gitelis.

“We’ve seen hemp-based material, we’ve seen bamboo, but nothing has the same stiffness properties of carbon fiber. One of the things that we get from carbon fiber that we don’t get from any other material is the stiffness characteristic. It’s this quality that makes a good bicycle frame.”

The bottom line

Carbon fiber is a remarkable material that enables us to ride aesthetically pleasing, lightweight and exhilarating bikes that provide a ride feel like no other material. So, the huge demand for carbon fiber frames is understandable.

But the carbon fiber landscape is multifaceted, with a stream of design, innovation, economic and environmental challenges. Evidently, there is a growing interest in making the material more sustainable, and I for one hope that we can find environmentally friendly solutions that enhance the material and our overall enjoyment of cycling.

Writers Credit: Emma Cole from Cycling Weekly