Carbon fibre has revolutionised cycling, from bike frames to wheels and components. Graphene, a super thin transparent form of carbon, could be the next big thing
What is graphene?
Graphene is derived from graphite, commonly found in pencils. It is a single sheet of carbon that is only one atom thick and some predict that it will have more of an impact on cycling than carbon-fibre.
It is said to be 200 times stronger and six times more flexible than steel, able to conduct electricity as efficiently as copper, to be superior in terms of heat dissipation to all other known materials, and to be almost transparent yet still impermeable- not even helium can pass through it.
Stronger and lighter
In 2004, two scientists at the University of Manchester managed to isolate graphene from graphite and their discovery subsequently won the 2010 Nobel Prize for Physics.
The material is said to have some exceptional attributes: much stronger and six times more flexible than steel; conducts electricity as efficiently as copper; dissipates heat better than any other known material; and is impermeable, even though it is almost transparent.
The potential applications for the next generation of cycling products are obvious, from lighter bike frames and wheels, to safer carbon rim brake systems, enhanced electronic shifting and even ‘smart clothing’.
However, not all scientists agree with the bold claims of this touted revolutionary material. Sir Harry Bhadeshia, Tata Steel Professor of Metallurgy at the University of Cambridge, says that on a small scale, graphene is substantially stronger than steel, but as much as claimed: “Graphene is a two-dimensional material. A perfect sample with a size about 1 millionth of a metre square is about six times stronger than steel of similar dimensions,” he said.
Professor Bhadeshia also confirmed that the main problem with the suggested benefits of graphene is that when you upscale to a tangible size, there will be imperfections in the material, and imperfections will cause weaknesses.
Application to cycling
To date, the cycling world has been slow to adopt graphene, but Italian company Vittoria is a strong believer in the material’s potential. It has spent five years researching its application and with its partner Directa Plus, has invested 45 million euros.
Vittoria says it has managed to combine graphene with both rubber and carbon to create new tyres and wheels. The tyres are said to have reduced rolling resistance, enhanced durability and better grip. Also, Vittoria says its wheels have 50 per cent more lateral stiffness, 10 per cent more heat dissipation and 18 per cent more impact strength while being 15 per cent lighter.
Rudie Campagne, president of the Vittoria group, believes they have only just touched the surface of graphene’s potential. “At this point we haven’t yet exploited the electric conductivity of graphene, so the cycling industry will likely benefit from this in the future. As graphene gets successfully applied to additional partner materials, either in the cycling industry or beyond, more unique properties will be unlocked.”
Other cycling brands have dabbled with graphene but do not share Vittoria’s confidence and, so far, have not taken it to production. Christian Wurmbäck, head of product development bicycle tyres at Continental, explains: “In the past we did some trials with graphene in the casing and tread of our tyres. However, although the directionality of the compound brought some benefits to the casing, the development of our Carbon Black compounds [which are said to use carbon nano particles] is at a higher level, so there was no need to jump back on graphene.”
Graphene is creating quite a buzz across a range of industries, but we are some way from understanding its potential in cycling. In theory, its strength, heat dissipation, conductivity and low weight provide almost endless possibilities — from lighter and stronger frames and wheels, to clothing that could be more robust as well as ‘smart’.
Only time will tell whether it revolutionises cycling. At present the main obstacles appear to be transferring graphene from a lab setting in its purest form into a state that it can be useful for mass production.
Lighter bike frames and wheels without any compromise in strength and durability; safer carbon rim brake systems and composite, rather than alloy, disc rotors; highly durable tyres that respond to the demands of your ride; improved and lighter electronic shifting; and cycling apparel that uses “smart technology” and offers extra protection. Graphene’s impact on cycling could be huge.
Is graphene the next big thing?
Yes: Rudie Campagne, President of the Vittoria Group
“It is inevitable that the cycling industry will embrace the graphene revolution that Vittoria has started. We will probably see the applications of graphene with rubber and carbon as a widespread practice in tyres, wheels and probably frames as well. Only time and costs are hindering this rapid development, because we have found no real downsides to the use of this unique material. This revolution has only just begun.”
No: Sir Harry Bhadeshia, Tata Steel Professor of Metallurgy at the University of Cambridge
“Unlike steel or carbon-fibre, graphene’s strength collapses as the size is increased. This is because one cannot rely on perfection. Nature detests perfection. Like carbon nanotubes, thermodynamics tells us that the mechanical properties of graphene cannot be scaled up with size. Based on what we know about graphene today, it will not replace carbon-fibre in bicycles.”
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Graphene products: Wheels
Vittoria’s first widely available graphene enhanced product was the Qurano wheel range, released at the end of 2014. Vittoria asserts that by integrating graphene into the carbon resin it has created a carbon-composite material that is faster, stronger and more durable than existing carbon fibre.
Campagne told Cycling Weekly that Vittoria uses two types of graphene to give its carbon wheels unique performance benefits.
“Our [Vittoria’s] wheels use two types of graphene, one on the braking surface to enhance braking and dissipate heat and a second version on the rim to make the wheels mechanically stronger,” he said.
Vittoria says that at this stage it has primarily focused on reliability and durability, however the next logical step is for the wheels to become lighter by using more graphene in place of other materials.
Graphene products: Tyres
Campagne told Cycling Weekly that by using graphene’s unique strength and flexibility properties that Vittoria has created revolutionary tyres: “The new tyres are faster, have much better grip and are more durable [three times more so than the non-graphene enhanced previous Corsa offering]; and the tubeless tyres have exceptional puncture protection.”
Vittoria claims that by integrating graphene into a rubber compound it has created a set of tyres that are not only the fastest tyres in the world but are also “smart tyres”.
The theory is that when riding in a straight line the rubber is at its hardest and has a low resistance, whereas when braking or cornering the compounds soften to offer more grip.
Can a tubeless tyre survive a nail?
The tread of the tyres is made from four different compounds: the centre of the tyre is designed to reduce wear and cutting; the middle shoulder is intended to increase grip; the outer shoulder is said to be extremely supple to give superior friction with the road when cornering; and underneath the middle shoulder is a super fast compound.
Vittoria would not reveal which compounds have graphene and how much, save that the super fast compound does not have graphene and that they can adjust the levels of graphene to create tyres for different conditions.
In addition to the above, when using sealant, Vittoria’s new tubeless ready tyres are claimed to be able to self heal almost all punctures. The modulus elasticity of graphene nano-platelets help close the hole made by the puncture.