How Canyon built its lightest ever carbon mountain bike

The Canyon Exceed goes lighter than ever before

Last year Canyon launched the new generation Exceed; an unapologetic carbon hardtail that’s designed to be stiff, efficient and ultra responsive. It also happens to be the lightest mountain bike that Canyon has ever built, with the top-end Exceed CFR coming in at just 740g for the bare frame. That is quite unbelievable for a bike that’s designed for actual mountain biking.

Also impressive is that the new frame has managed to drop grams over the old version despite becoming longer and slacker overall. Additionally, Canyon also says the new frame is even stiffer in key areas. Along with a whole suite of other improvements, it all adds up to a scary-fast race bike that thoroughly impressed us with its precision, power and purpose. If you’ve not read it, be sure to check out our Canyon Exceed review.

To reduce weight and achieve those lofty stiffness-to-weight ratio goals, Canyon turned to a mysterious type of carbon fibre to build the Exceed CFR frame. We briefly touched on this in the review, but in this feature we’ll be taking a deeper dive into the black magic that lurks beneath the gloss white paint job. Here we’ll be discussing exactly what it is, what makes it unique, and how Canyon has used it.

‘Unicorn Hair Carbon’ – what is this stuff?

The Exceed CFR is made with a special type of carbon fibre that Canyon calls ‘Unicorn Hair’. Its real name is actually M40X, and it’s manufactured in Japan by Toray.

The reason for its nickname is due to the high price of the raw material, its unique properties, and the fact that it is extremely exclusive. At this point in time, only three manufacturers in the world have access to M40X carbon fibre.

While it is also used in aerospace applications and in the production of high-end baseball bats and badminton racquets (which require very high strength and low weight), Canyon’s vendor in Asia is the only factory that is producing bicycle frames. Given it’s so hard to source and somewhat cost prohibitive, it’s likely to stay that way for some time.

How is M40X different?

We had visions of scientists dressed in full hazmat suits, performing morally questionable experiments in an underground laboratory while ominous machines bore deep into the earth’s core to extract the highly volatile M40X element in order for Canyon to make bicycle frames out of it. Sadly, that turned out not to be the case.

Indeed as a raw material, M40X appears much like normal carbon fibre, and it’s treated in exactly the same fashion. The only way you could spot the difference would be with the assistance of a microscope.

Zoom in further and you’ll find that it’s within the actual production processes where M40X differs from conventional carbon fibre. According to Toray, the key is in improving the orientation of the carbon fibre by closely controlling the crystal structure of the graphite at the nano level. How the heck they do that is miles beyond our comprehension. The Japanese brand doesn’t divulge a whole lot of information on that topic, which is to be expected given all the patents and such. But in short, the way the raw carbon fibres are produced is more tightly controlled to deliver a higher level of consistency, when compared to conventional fibres.

Additionally, M40X also employs Toray’s proprietary Nanoalloy mix within the resin. The result is a claimed 30% improvement in tensile strength, along with greater compressive strength and increased shock resistance, while retaining the equivalent tensile modulus of conventional carbon fibres.

And herein lies the magic.

What’s so good about it?

Typically, most types of carbon fibre offer either high tensile modulus or high tensile strength. These two attributes are normally in a trade-off relationship, so the higher the tensile modulus (stiffness), the lower the tensile strength. Most carbon fibre frames are made using a combination of these different fibres, in order to get a balance between strength, durability, and stiffness.

Where Toray’s M40X differs is in its combination of strength and stiffness in the single type of carbon fibre.

“M40X combines high compression strength and high tensile modulus”, explains Johannes Thumm, Product Development Engineer at Canyon Bicycles. “Both are needed on the bike. So instead of working with ‘high strength’ and ‘high modulus’ fibres separately, you get both attributes with one fibre type only.”

Being able to use one type of carbon fibre in an area that you’d normally have to use two types presents obvious advantages. Not only is that structure going to be simpler to manufacture and easier to achieve a more consistent finish, it’s also going to be lighter.

Pushing the carbon envelope

With those desirable attributes, utilising M40X provides two opportunities. You can either make a frame or component at a similar weight but with greater strength and stiffness, or one that is significantly lighter while retaining similar strength and stiffness.

In Canyon’s case, the engineers employed M40X to elevate the stiffness-to-weight ratio of the Exceed CFR frame. The tube walls are made very thin to help reduce weight, but overall stiffness has actually improved, with the headtube and bottom bracket seeing the largest gains.

The advantage of M40X can then be seen when comparing the top-end Exceed CFR frame to the SLX and CF frames. These frames are used on cheaper Exceed models, and they’re made from more conventional carbon fibres rather than M40X. Shown here are the claimed weights for a Medium frame, including hardware and graphics;

• Exceed CFR – 835g
• Exceed SLX – 1,105g
• Exceed CF – 1,312g

While we are only talking hundreds of grams here, the Exceed CFR frame is 25% lighter than the Exceed SLX, and a whopping 37% lighter than the Exceed CF frame. In the world of weight weeny carbon hardtails, that’s a lot. And M40X is a big reason for the weight differential.

What parts of the frame is it used in?

Around 50% of the Exceed CFR frame is manufactured from Toray M40X.

“It is used in areas where we need good compression strength plus have high bending moments, like in the transition between the head tube and downtube”, explains Thumm. “Also, we use it in the main layers in the downtube to push torsional stiffness”.

The rest of the frame is made up of a blend of high modulus and high strength fibres.

“Of course in some areas high tensile modulus fibres like MR60J or high tensile strength fibres like T1100 still have benefits”, explains Thumm. This is to say that while M40X strikes an appealing balance, if you’re after maximum stiffness in a particular zone on the frame, then a more conventional MR60J fibre will actually offer a higher tensile modulus.

What collage of carbon fibre plies you end up with really depends on the specific load requirements for each part of the frame. “You have to know the main stress directions for efficient use of the material”, states Thumm. “Each added material increases stiffness and strength, but the question is what is most efficient while keeping the lowest possible weight?”

If that load requirement checks out though, then it’s possible to take full advantage of the Goldilocks qualities of M40X. “In many areas you can work with M40X only, and thereby save weight”, explains Thumm.

Why not build the whole frame from M40X?

Well for a start, it’s very expensive. According to Canyon, the Exceed CFR frame is twice as expensive to produce compared to the same frame made with conventional fibres. So while you could build the whole frame from M40X, such a frame would then be twice as expensive again.

Canyon’s Senior Product Manager and all-round speedy XC whippet, Julian Biefang, acknowledges the commercial limitations of employing its Unicorn Hair for the entirety of the Exceed CFR chassis. “It simply does not make sense to use such a high cost fibre in everywhere”.

And in fact, it doesn’t make sense from a functional standpoint either. As mentioned above, conventional fibres still hold an advantage in terms of ultimate stiffness or ultimate strength. Yes M40X is an important ingredient for the Exceed CFR frame, but it isn’t the only ingredient.

Hold on a second, aren’t all carbon fibre frames the same?

“All carbon frames come out of the same factory anyway!”

“They’re all the same, they just change the stickers!”

You’ve read those claims in an online forum before right? Conspiracy theories along those lines have been bouncing around the internet for decades, but the reality couldn’t be further from the truth.

There’s actually a considerable number of factories that produce carbon frames for numerous brands, with some of the best-known and well-regarded manufacturers being Giant, Merida, Quest, Topkey, G&M Carbon Components and Ten Tech Composites. Canyon doesn’t divulge which factories it works with, though we were able to confirm that it enlists more than one factory across the production of its carbon fibre product lineup.

As for the carbon itself, the majority of the raw material is produced in Japan by three major companies; Toray, Mitsubishi and Toho. Furthermore, there’s a whole range of carbon fibre types including 12K, 3K, unidirectional and spread tow. You can have different area weights, resin types and content, not to mention the different techniques used to curate the ply shapes.

Oh, then there’s the method of how the plies are laid up, what moulds are used, how the frames are baked, finished… Indeed the possible combinations are rather mind-expanding.

How are the Exceed CFR frames made?

As mentioned earlier, the factory that produces the Canyon Exceed CFR frames is currently the only bicycle manufacturer working with Toray M40X.

Interestingly, this same factory also produces the Exceed SLX and CF frames. This means that all three frames are produced by the same staff, with the same moulds and production techniques. They utilise exactly the same in-house testing, gauges and tolerance checks. And of course they’re leveraging the same ongoing manufacturing experience too.

This may seem logical, but it’s not always the case in the bike industry. There are other brands that will have one factory produce their high-end frames, and a different factory produce their lower-end frames. This is primarily due to cost reasons, and it often means that the cheaper frames can be built to a very different standard. In the case of the latest Exceed however, it all happens under the same roof.

Getting hands-on

As with the other carbon fibres that Canyon works with, Toray M40X is delivered in pre-preg form to the factory, and the way it’s handled is exactly the same. Various types of pre-preg carbon fibre are then cut into hundreds of very specific shapes to be laid up in the mould, like a big carbon jigsaw puzzle. The smallest pieces measure around 1cm², while the longest pieces run along the entire length of the downtube.

There are a few less jigsaw pieces used for the Exceed CFR frame though. “Due to the usage of the specific M40x fibre, we can use a little less overall”, explains Biefang.

Unlike a lot of alloy production that can be automated, carbon fibre frame production is very hands-on. When any brand refers to a carbon frame being ‘handmade’, they aren’t lying.

According to Biefang and Thumm, each frame takes around 15-24 hours to build. There’s a minimum of one person for each manufacturing step, so once you factor in material preparation, layup, quality control, bonding, sanding, finishing and painting, plus all of the management and production engineers, there’s around 20 people in total who are involved in producing a single frame.

Within that production process, quality control and unearthing defects is of paramount importance to Canyon.

“A carbon frame is the result of many manual process steps”, explains Biefang. “You cannot completely avoid human mistakes, but you can reduce systematic and random failures and have a well-working QC system that filters the errors.”

Like many of the big brands, Canyon utilises numerous filters for this QC process. However, it also famously employs CT scanning, which isn’t common in the bike industry. Every single carbon frame, fork and cockpit is scanned at the factory to identify any imperfections and voids within the carbon walls. At the assembly facility in Koblenz, each carbon fork and cockpit meets the CT scanner again, while frames are batch tested – whether they’re made with M40X, or not.

Canyon won’t tell us the exact failure rate, though Biefang states that “the percentage is really low in general and in a lower single digit area”. The advantage of this extra step is that those defective frames and components can be removed from production, before ever ending up in the hands of a customer.

Where will we see M40X used next?

At this point in time, the Canyon Exceed CFR is the main product to make significant use of Toray’s M40X carbon fibre. The latest Aeroad CFR, Canyon’s premium aero road race bike, features a small amount of M40X. Small patches are also used in the construction of some of Canyon’s one-piece cockpits.

Will we see M40X used significantly in any other new Canyon models? “Yes, but it doesn’t make sense to use in all applications”, states Biefang.

Given the advantages the wunder-material offers, we’d expect to see its usage increase, particularly as Canyon builds on its ongoing manufacturing experience. Still, the high cost and exclusivity means it’s unlikely to be adopted across the full bike lineup.

Reading between the lines, you could assume that the Sender and Strive are the kind of models where M40X doesn’t make sense. The applications where it does make sense are at the higher-end of the price spectrum, on models where low weight is of utmost priority. With that in mind, our suspicion is that the next generation Lux will be offered in a CFR-variant with M40X. However, Canyon is remaining very tight-lipped about such a product.

Conjecture aside, we’ll just have to wait and see where Canyon takes its enthusiasm for M40X next. In the meantime, if you’re keen to hear about our on-trail experience with Canyon’s lightest mountain bike, be sure to check out the Canyon Exceed review.