Are Carbon Fibre Bicycle Components Prone to Catastrophic Failure?

Long time Choice subscriber here. I have no conflicts of interest to declare. Like many Australians, I have found myself cycling more during the COVID era. On researching the subject of buying a new bike (the bike stores all say they are low in stock as they’ve sold out), I found some rather shocking things about the poor quality controls in place to ensure the structural integrity of carbon bike frames, which unlike metal frames failure suddenly, unpredictably, and catastrophically.

There are services in Sydney and Melbourne that conduct ultrasound examinations on carbon bike frames. One of these is Leuscher Teknik in Melbourne run by Raoul Leuscher. He has a very helpful YouTube channel where he dissects carbon frames looking for defects in manufacturing and the results are quite scary. Frames that cost thousands of dollars can have terrible invisible defects that weren’t properly screened out during quality control. These defects are visible only on ultrasound. He even found them in the forks of a company (Canyon) that claims to screen their carbon frames with CT scans. Leuscher mentions on his review of a BMC bike that the brand became popular in Oz after Cadel Evans won the Tour de France on a BMC but the structural integrity on the inside commonly leads to frame failure due to shortcomings in manufacturing.

Leuscher has been asked by the Victorian Coroner to investigate cases of carbon frame failure such as reported here:

In this case, the fork of the carbon frame failed catastrophically causing the rider to hit his head on the road, leading to his death. That was on an old bike frame which highlights the fact that you should not buy second-hand carbon frames because you don’t know if it’s been involved in an accident causing damage to the frame only visible on ultrasound. Even something minor like hitting a pothole can bring out manufacturing flaws with catastrophic results.

However, this is not just an issue with second-hand frames but you come across reports of it happening with brand new frames as well (note that an S-Works Roubaix costs around $15K):

“A good friend of mine had a very serious accident riding a new Specialized Roubaix S-Work, the front fork collapsed while he was on a fast descent due to a manufacturing flaw in the fork. He’s lucky to still be able to walk, but will live with back pain for the rest of his life.”

There are no legal standards with respect to ensuring that carbon bike frames are properly scanned for defects at the time of manufacture. This makes it tempting for makers to cut corners to save on costs, which is unacceptable given we are being charged thousands for these bikes. Leuscher mentions on YouTube that Giant will immediately replace a frame where defects are found on ultrasound, no questions asked, but that Specialized flatly refuse to acknowledge the problem.

I have found similar services that do ultrasound scans in Sydney. Leuscher even recommends that you shouldn’t ride any carbon frame bike until it has first been scanned by an independent assessor. Some may say he is scaremongering to sell his services but the evidence of frame after frame with structural defects speaks for itself.

Would it be possible for Choice to investigate using ultrasound scans to see if common bike brands sell frames with serious structural defects? Or at least if a journalist could interview Raoul Leuscher and others who do frame integrity scans in Australia for their perspective. Many end-users may be at risk of serious injury or even death as a result of shonky manufacturing practices. The only way to eliminate this is by legislation enforcing minimal safety standards during the final QC step.


A dedicated longer distance bike rider @gordon might be one of the better placed ones to weigh in on this matter. I personally don’t so my thoughts had been that carbon fibre was a great material but as you point out defects could lead to very unwanted outcomes. As they are expensive items (carbon fibre being an “elite material” cost wise you would tend to think that a scan and or some really decent quality control would be incorporated into that cost.


Although carbon frames are still regarded as a high-end or luxury item, they are becoming increasingly common. They are being offered at ever lower price points compared to a decade ago. You can also pick up a second-hand carbon frame for much less as they don’t hold their value. You may think you’re scoring a nice bargain but are consumers buying into a potential death-trap unless you pay around $2-300 AUD to have your frame scanned before buying?

We are also seeing more and more eBikes on the market and many of these are offered with carbon frames. Due to climate change, cycling is becoming more fashionable and the UK are even offering tax rebates on bikes used to commute to work. COVID has accelerated this process incalculably. The shelves of Victorian bikes stores will probably have been stripped bare, if what is happening in bikes stores here in Sydney are anything to go by.

When I last brought a bike in 2014 I decided on an aluminium frame. I’m glad I did because metal fails more gently and predictably as it usually cracks and deforms before failure. Leuscher’s cut ups show that manufacturing processes are improving and that carbon frames from around ten years ago have more defects (voids and wrinkles) than the current ones. But we, as consumers, must be savvy buyers and demand basic safety standards when there is potential for permanent injury or death.


BTW what brought me here was finding this Choice guide to buying bikes:

Carbon fibre

Not common on city-style bikes

  • Pros: light; absorbs bumps
  • Cons: expensive

No mention whatsoever is made about safety concerns and lack of legally enforced manufacturing QC standards. Nor is mention made about potential safety concerns with older second-hand frames. It is also a bit out of date in that more and more eBikes for city commuters are being offered with carbon frames. Safety concerns with carbon frames thus increasingly affect the wider community of consumers and not just a small bunch of young racers and their foolish bravado making them all too willing to sacrifice safety for speed.


Just back from a 106km ride on the Titanium framed gravel bike, which has a carbon fork, but I would not buy a carbon frame myself, as I suspect it would have a very short life span.

Tamworth Regional Council maintains my road in a diabolical condition with thousands of corrugations,
potholes and loose gravel (most of which remain after they repair the road with a front end loader and piles of loose rocks!), which has resulted in 8 broken Aluminum and Titanium frames over the past 12 years when riding along this road, or immediately afterwards. I’m always listening out for new noises, which could indicate a crack developing, and I’m pretty sure carbon fibre frames would give similar noise warnings , ie there would usually be some warning of imminent failure, but not all, actually probably most, riders would not be alert to that. I’ve found all the cracks in my Al and Ti frames before any catastrophic failures, but these are certainly possible with these metals (and steel) if you ignore the signs.

Yes carbon fibre is strong, but it is also brittle, and one deep scratch could well mean the frame needs replacing, or at least an expensive repair job, as a break could occur due to the scratch weakening its structure.

Various important components of a bike can be made of carbon fibre, such as handlebars, seat posts, forks, but IMO you should be checking these for signs of cracks/failure quite frequently, especially if you reach high speeds during rides.

2nd hand carbon fibre bikes? Only ridden to church on Sundays? :wink: Just say no!


Yes, agreed it’s false economy to buy second hand carbon bike components. You’re just putting your safety at risk. Sadly some of the brand new frames being sold for thousands of dollars by coveted labels can’t be guaranteed to be much better either.

Dear Choice please make consumers more aware of these issues in a future update to your review of buying bikes. Bike mags/websites often focus too much on the cool factor for going faster in the Tour de France while safety issues are rarely addressed in a technically proficient way. Too many so-called “independent bike reviews” just regurgitate the manufacturer’s PR material. We need consumer advocate bodies like Choice to speak up for us when our health and safety is at stake.

I’ve also read that many manufacturers don’t individually QC each carbon frame for defects like voids and creases. They just sample a small proportion of a batch and if these show defects this triggers more testing. Really, each frame needs to be individually scanned by ultrasound or CT scan. Until this is legally mandated as a minimum safety requirement, makers will cut corners.

An example of sudden and unexpected catastrophic carbon fork failure in the middle of a sprint in the Tour du Doubs:

And no he wouldn’t have been riding a second-hand frame…


The more often a Carbon fibre composite is highly stressed the weaker it becomes. IE the more stress cycles the weaker the material becomes as it ages.

As @gordon also suggests brittle failure is typical. Brittle failures can be rapid with little warning. Various options for NDT may provide some insights. It’s also possible that NDT cannot provide a reliable one off assessment. Without knowing the full history of a frame or high stress item, and how it has been loaded the safe remaining life may be difficult to determine.

Detecting serious defects in a frame etc prior to a failure may just be good luck on the day. The first jet aircraft airframes were designed to save weight and suffered numerous stress related failures, catastrophically. More modern aircraft use lower stressed designs with airframes intended to last longer without failing within the design life of the aircraft. High performance military aircraft have strictly monitored use and life cycles, as a consequence of taking design to the ultimate limit.

Ask the same of a high performance racing or road bike it will be designed to save the last few grams, with a limited design life the outcome. With the ultimate measure of bike owner importance for some being the lightest weight, is this the real cause of concern?

As an alternate way forward do composite bike importers and manufacturers need to assure the design outcomes for the intended use of their products? All to have a date of manufacture and design life clearly imbedded on the item. Professional bikes and racers xyz months. Road training bikes abc hours of use or ZZ years. Consumer products a fixed number of years assuming casual use once or twice a week for a few hours each time. Our standards put finite life’s on many items because there is no assurance the items perform or are safe to use after an expiry date. Where the lure of carbon fibre and light weight is so important, replacing your frame as directed might be the better option.

No disagreement concerning Inspection and testing at manufacture needing to meet a minimum standard.


I agree that a consumer advocacy journalist would need to do some homework asking engineers about the pros and limitations of regular ultrasound-based non-destructive testing (NDT). Should either manufacturers or bike shops be made to offer NDT as part of a regular service check-up for their frames? Or should there be a lifespan limit in terms of time or kilometres on each frame? As mentioned, a commercial or military aircraft would probably have to undergo regular mandatory NDT of structural integrity so why not have similar safety recommendations (or even mandates) for bicycle frames? This is where getting expert engineering advice would be informative if the framework for a national safety guideline were to be drafted.

BTW my source reference regarding the selective QC process of batches during bike manufacturing is this article:

If a frame company is making 1000 frames for you in five sizes, the general QC process in anywhere in Asia is 10 per cent of each size is QCed, with 100 per cent of all critical damage specified, measured and reported. If more than 50 per cent of those fail they do another 10 per cent. If 50 per cent or more of those fail again, you do 100 per cent QC [of that batch]. So not every frame is checked as a standard process. Some brands may decide to pay more to have more checked, or even more to have everything checked.

It suggests that it would be a highly unusual practice to have each individual unit QCed for structural integrity and hence safety.

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There are to my knowledge many professionals, lawyers and engineers included who not only ride daily, but who have invested in expensive light weight road bikes.

It’s wisdom to leave it to an expert panel to decide. Standards Australia and our legislators know how to. The outcomes are not assured, or rather the solutions we might think we know may not be what they decide.

It’s one possible recommendation. It has a strong appeal, especially to those selling the services. How could anyone not agree, lives are at risk?

Caution is advised, as until the appropriate expertise and supporting evidence available any potential benefit is unproven. The Engineering materials science applicable to carbon fibre composites suggests the fatigue life of the product is finite. IE It will inevitably fail, even when free of gross defects. Separating age or use factors from manufacturing influences, and correlating them to what NDT might reveal is not trivial.

Major defects in manufacture are not the only possible cause of failures. In which instance can there be any confidence frames testing free of defects cannot fail? Without a definitive answer to that proposition, is it better to leave the solutions to others?

As to failures, leading to minor or serious injury, Australian Consumer Law demands products are fit for purpose. A different point for discussion is whether the retailers selling the bikes as noted advise that their products are unsafe if not regularly tested or unsafe after a prescribed lifetime. It would seem they are open to litigation if frame or front fork failures are able to cause serious injury?

I won’t admit to any expertise in this matter, but professional judgement requires I ride a well made steel framed bike. Light weight isn’t everything, unless you are genuinely racing for gold on the day.

That is variable based on ‘make and model’ and airworthiness directives that apply. The frequency is flying hours, years, or take-off-landing cycles and it is not cheap. I believe a B737 costs about $USD80~160,000 for a ‘C-check’, model and age dependent. There are also more extensive ‘D-checks’. Even a single engine prop annual inspection is often in the $1,000’s and if there is an airworthy directive needing to be done, that can add from near $0 to $10,000’s dependent on its complexity and parts requirements. Bicycles should be much less :wink:

Highlighting a catastrophic failure in a custom racing bike during a race is educational in how they can break, but is a Renault F1 car losing a wheel in a race indicative of driving a Renault street model?

An honest question is how many injuries and deaths are recorded annually from bicycle frame and component failures? There seem to be lawyers eager to sue over frame fails resulting in injury or death, but are there statistics? All I could find are essentially road deaths (eg vehicle/pedestrian related accidents).

Noting most are imports, the overall costs of trying to enforce pre-emptive safety versus the benefits always weighs, not considering the legal issues involved. I am not aware of many things that are rigorously 100% tested; statistical sampling has been the norm for decades.

Some consider no cost is too much to potentially prevent a single death or injury yet others put values and prices on same. As a sobering thought, consider that Australia has very lax to no laws about the safety of most (only many?) products. There are standards but many are voluntary and a few seem to put the onus on the end buyer not the supplier. It is also legal to sell dangerous products although there are exceptions. Note motor vehicles are not universally subject to annual safety checks in some states, just when on-sold.

I doubt many ‘pedestrian’ cyclists such as myself are aware of how frames, and especially carbon ones, can break, but other than publicising it and encouraging an NDT industry at bike shops for those so inclined to take advantage, I suspect regulation would be a serious uphill trek. As was mentioned, serious riders are usually aware but CF is finding its way ‘down’ the chain to trusting individuals. Across the general bicycling population how many DIY maintenance regardless of skill or knowledge versus how many get shop service? Yet another issue.

That might get the message out as well as encourage speciality magazines to start taking notice, and perhaps get government to mandate a safety notice about frame integrity be provided with each bike. I did a survey of 3 owners manuals and none called out the possibility of a carbon (or any) frame breaking except as a result of damage from car carriers, mishandling, and accidents, and then only glibly so. Even then, everyone reads all the cautions and instructions and abides by them, right? Another regulation requiring us to read the 4 pages of cautions?


What is the rate if failure…1 in
10, 1 in 100, 1 in 1000, 1 in million etc of carbon components/frames/forks?

This is very important to determine the risks of potential catastrophic failure resulting in an incident and whether risks are acceptable or over/understated. It is also relevant to warnings and whether they should be given

While any failure leading to injury could be argued as unacceptable, nothing we do has zero risk. Catastrophic failures occur infrequently in other products…cars are one example or even household carving knives or ladders. Should all these products also go through rigorous QC testing which currently doesn’t exist…to ensure the product has lower (catastrophic failure) risks.

What is the risk of use causing injury through use (non-failure) events comparing to where catastrophic failure occurs? This is particularly important for regulators as the cost for imposing QC on a product may have a better return when spent on when any high risk products are used.

Notwithstanding this, if consumers are concerned that a particular product hasn’t met their own expectations for QC testing, one has the possible choice to find one that does or to conduct their own testing should they be overly concerned (such as a professional rider on custom racing bikes, buying second hand bikes or bike of any frame material being in a incident where frame damage could have occurred).

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Carbon fibre frames are not the only material capable of catastrophic failure on bikes- over the years in addition to the frame cracks I’ve had in Al and Ti, I’ve had 4 Al crank arms snap and 3 steel pedal axles snap, all but one of which resulted in a crash and injuries, although none so bad that I wasn’t able to walk/roll/pedal with one foot back to where I started. Rather inconvenient when that was 25km away up an 800m high mountain!
The pedals were all only 1-3 years old, 2 different models, Crank Brothers brand, a company whose products I avoid like the plague these days! Having a greasy snapped pedal axle gouge into your leg is not a fun experience!


Ouch! Glad to know the outcome was survivable, just?

Not to excuse shonky products:
Are such failures subject to warranty?
Or does the supplier avoid the responsibility because the components fit into a special class of lightened for high performance, no warranty applicable?

As @PhilT has suggested, there are differences in expectation of safe performance in everyday use of products, and those used for high performance.

Is there is a blurring of expectations where the desire for premium has created a market that is not meeting needs? IE High performance quality components with limited life, and a range of poor quality knock offs made to a low cost to exploit premium prices.

? Time to horse power rate bikes to riders?
Upgrade! Can you handle the new XYZ 2500.1? It’s load tested to 100,000km at 2500 Watts! Is boasting the power rating of your bike the way to change thinking about light is great?

Yes, I find the thought that the lighter a bike is the less likely it is too fail a contradiction. It appears the industry and some riders are just test pilots. Engineers build bridges with extra material and strength (factors of safety) to minimise risk. If you are not racing for gold the logic of lighter is best defies my common sense. What’s the problem with riding with an extra few kilos?

Added note:
For those who have some further interest in carbon fibre composites one source of background and testing of the material in fatigue.
Note the test results are for defect free laboratory specimens. The greater the peak stresses in use the less the fatigue life.


There is also another agency tasked with Consumer Safety issues and this is the ACCC. They would have stats on frame failures, I’m sure they have complaints on file about them. They can determine what is an unsafe practice, part and product. They even press the Govt to legislate necessary rules around QC, inspections aftermarket among other factors including dangerous parts eg Takata Airbags.

You can also raise a complaint with them as individuals concerned with safety issues. I don’t see them having done much in this area so some critical mass of a mix of complaints and failures must not have been reached (whatever that level needs to be is opaque). Perhaps a social campaign of complaints to them might extort them to effort…eg a Facebook (shudder) one, or a type, or a Twitter one are a few examples that do not require any organisation backing or much effort to start.

CHOICE certainly can put their weight behind a campaign and undertake investigations and lobbying but I would think it needs some decent level of safety concern or public interest to drive that. I know they review all requests and they often pass requests onto their investigation teams even if little public interest is obvious. Statistics could/would be a help in that, if any are available as pointed out above by @PhilT, @phb and @mark_m. It would also be a strengthened cause if more people would add their weight to get such a campaign/interest and so perhaps a public petition might be a way to go to show that there is enough public interest.


In terms of the counterargument that insists that a thorough (ie time-consuming and expensive) epidemiological risk assessment has to be undertaken before any recommendations (let alone legally enforced mandates) are put into place, there is the danger that this is precisely the defence that the bike manufacturing industry is going to put up. They will also say all sporting activity involves consensual end-user acceptance of risk (eg horse riding, skiing etc) and that onerous impositions on them by the “nanny state” to totally eliminate all risk is absurd, utterly unrealistic, and hence should not be undertaken.

The truth is they are selling us carbon frame bikes for $12-18K (complete build) with holes in them. The proper term is a “void”. These can run along either the length or width of the section and aren’t visible eternally but when present at a critical juncture can predispose it to structural failure.

In terms of costs for identifying such holes and other defects, I found a local Sydney business (Carbon Bike Doctor) that does a full frame and fork NDT check for $380 on Google search.

Leuscher doesn’t have his prices up online. So the price for a check isn’t ten of thousands of dollars as some might have imputed. With some manufacturers, it appear such holes are all too common.

Some makers such as Canyon claim to be doing CT scans during their QC but Leuscher still finds problems on their forks suggesting that they do not check each frame/fork separately but that they test only a percentage of each batch:

Given that you are paying thousands for the bike anyway what is another $380 extra manufacturing cost to ensure additional safety from weeding out defective frames with holes in them? And why should such a basic QC step be left to the end-user to sort out? As Leuscher says the manufacturer will put up all sort of resistance to fix the issue by denying a problem exists, questioning the expertise of the examiner etc, and you may need to go to the ACCC or hire a lawyer before they act. Bike shops are hardly going to encourage you to undertake pre-purchase NDT either but instead give strenuous “reassurance” that no such problems can possibly exist.

As for issues related to inherent manufacturing defects vs defects acquired over time, these aren’t mutually exclusive. Having voids (holes) or wrinkles (where a carbon fibre poor area of weaker resin pools) sets up the frame to acquire defects over time. Failure tends to occur more often at inherent manufacturing defect-points especially where these are present at high-stress critical junctures. Why not push or even force manufacturers to eliminate the holes during QC? At the very least force them to declare whether such an NDT QC step has been individually undertaken on each frame/fork while recommending that buyers be allowed to ask bike shops for a 3rd party NDT check prior to purchase.

And yes metal bikes can fail too but at least they don’t charge you thousands of dollars extra for the holes. They use ultrasound based NDT in other industries to look for areas of metal fatigue:

Politics and legislation is at the end of the day, the art of the possible, usually initiated by some evidence whether real or imagined, yet excellent evidence is often insufficient to carry a day.

It is apparent you are very passionate about this issue and I detect some pushback from you on honest issues, questions, and discussion in taking it forward, so I for one will step back.

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I suspect most do not get reported to the ACCC. I’ve certainly never reported any of my frame failures, and I know of others who have not reported them.

Yes, but one crank failure was in traffic and could have had a much worse outcome than the bruising and missing skin!
Frames generally have warranties from 1 to 5 years, although some claim a “lifetime warranty”. We’ve all heard of those before! Some sort of undefined lifetime of the product, not the user!
My last Ti frame crack late last year was covered under warranty, although it took a bad review before they acted (in the UK). It was only 6 months (and 11000km) old.

Nothing if you are riding to the shops on a flat bike path, but much more of an issue on a 250km ride through the mountains!

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I have been involved in the bicycle industry for over 35 years, but retired from it for 10 (although ‘keep in touch’) Retail, wholesale/import, manufacturing. There are things I’ve seen that I would not prudently state in a public forum. That said, all materials have a fail point and it’s due to many, many factors. When asked what frame material to purchase I always recommend steel, followed by titanium - both recyclable, easy to manipulate, good to ride. But one is out of fashion and the other is expensive. Carbon is a toxic substance, tricky to build well and a cash cow for suppliers. It’s important to know that any material can be made cheap, well, very well, extraordinarily well: depending on the intended market/use. More advice: always buy the best you can afford plus a little more. I won’t provide names but can say that 20 years ago we were experiencing a 40%+ failure rate on a particular carbon frame; the manufacturer accepted this as a cost of doing business and was quick to supply a replacement. The junk was hard to get rid of.
I could go on and on about this subject but for the sake of the thread will suggest a review of the AS based upon manufacturing processes; not an easy ask by give it is quite detailed already could be achievable.


The three videos aren’t want one would call independent. Luescher Teknik may be a credible business but it is also in the business of doing carbon bike testing. While they could have accurate information, it would be better to get information from say a bike riding association, the insurance industry or other party which does not have a direct interest in promoting potential problems or risks with carbon bike frames.

Yes it does… see this …which if one doesn’t wish to download the pdf, is summarised as…

Carbon Bicycle inspection services and fees
:black_small_square: Standard Inspection fee full Frame and Fork only $410
:black_small_square: Standard Inspection fee full Frame only $305
:black_small_square: Standard Inspection fee full Fork only $200
:black_small_square: Standard Inspection fee small local area damage, frame or fork $130
:black_small_square: Standard Inspection fee complete wheel rim $200
:black_small_square: Standard Inspection fee other parts,
:black_small_square: Seatpost $130
:black_small_square: Full handlebars $200

I can see the merits of testing a used bike to see if it has been subject to a event which may have caused damage which isn’t visible to the naked eye…especially if one is spending a considerable amount on a (second hand) bike an wishes to ensure its integrity before committing to purchase (like taking a second hand car for a thorough inspection before purchase for peace of mind).

I wondering if you do as there seems little independent evidence that there is a major problem within the bike industry (there is information that seems to indicate the risks are very low). Do you have any relationship (personal or professional) with Leuscher Teknik or have an interest or business associated with the bike industry?

Or is it a case of believing one source without seeing a range of difference sources for balance?

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No the only “relation” to Leuscher Teknik I have is watching his YouTube videos. I am in a biomedical industry in a professional consulting capacity and have never had anything to do with the cycling industry. Nor have I ever belonged to a cycling club and don’t post on any cycling related websites. Until COVID hit and the gym closed I hadn’t ridden my bike for something like a year. I’ve been a Choice subscriber for well over 10 years and it’s nice to have info to guide you about which washing liquid gets the stains out best but the thing that is of concern here is that it is something that can potentially impact your health, perhaps even kill you. As a consumer I not have a right to raise my concerns about something that could kill me without being accused of being a shill but it is moreover an ethical duty to warn others. Where there is potential for injury and death, safety concerns raised must not be trivialised or dismissed as petty sensationalism driven by secondary gain. At least in my industry that is the standard ethos. But I see that elsewhere an ethos of shooting the messenger prevails.

Oh and when I brought my aluminium frame bike in 2014 because of concerns with potential for catastrophic carbon frame failure, Leuscher didn’t have a YouTube channel. Until a couple of weeks ago when I started researching buying a new bike I had never heard of him.

I did look on the Leuscher site, which is in Melbourne anyway so I wouldn’t use his services since I’m in Sydney. I couldn’t find a price list easily on his website.