This article was produced in association with Vittoria
Towards the end of his career, the great time trial specialist Tony Martin gave an interview providing some interesting insight into his chosen discipline. Training, the German opined, will only take you so far. To succeed, you also need to work on your equipment, your position, the distribution of efforts, the incorporation of new technology. These were the areas where real gains were made.
There’s no doubt that TTs are a unique proposition. The rider is exposed to the wind the whole time, without the benefit of slipstreaming other riders, which makes it totally different to a normal road race. And no rider, least of all at WorldTour level, can win a time trial based on their talent alone. Time trials are a solo effort, but they’re won thanks to teamwork behind the scenes.
Behind every TT victory is a massive collective effort, a bit like Formula 1. And like F1, the technology that makes that TT victory possible eventually trickles down, in various ways, to the real world and the bikes the rest of us ride. While a team’s innovation or technical development might not be good news for their competitors, it’s great for us amateurs, because sooner or later we’ll benefit from all that equipment development and technological research.
When it comes to tyres, a lot has changed recently. So in an attempt to better understand the quality and characteristics of these new-generation tyres, we teamed up with Vittoria to explore how much the cycling experience can change by simply using different tyres.
Beyond the limits
‘Marginal gains’ is a term we’re all familiar with these days. Once an athlete has reached the theoretical limit of performance through training, gains need to be sought out through the choice of equipment and technical innovation. There is a lot of potential for improvement this way.
In recent years, the main innovations in this area have come from the adoption of wider rims and bigger tyres. The benefits in terms of both performance and comfort are significant, and it’s easy to see how a larger tyre used at a lower pressure can more efficiently absorb road roughness and imperfections, thereby reducing fatigue.
On top of that, thanks to the larger contact area it reduces rolling resistance and improves braking, not to mention grip in the corners.
Low pressure, wide tyres
To anyone who’s been riding for a long time, the principle might seem counterintuitive, because for years the prevailing wisdom was that skinny tyres pumped to high pressures were the fastest. In our heads, it feels like a skinny tyre that provides a stiff interface between the ground and the rim would ensure faster speeds with the same pedalling force. But in reality, this is only true on perfectly smooth, homogeneous surfaces like the track of a velodrome – which is why track cycling tyres have remained largely unchanged.
There are at least three reasons why a larger tyre offers better performance on real world roads. Firstly, friction, or rolling resistance, is lower. Aerodynamic resistance is also lower, thanks to a smoother rim/tyre profile and better overall wheel shape. Lastly, as the wheel rolls more smoothly on the tarmac, suspending the rider from the ground and isolating them from more vibrations, the contractile ability of their muscles also im- proves. And due to this decrease in vibrational stress, fatigue is also reduced. Essentially, using tyres inflated at low pressure on rough tarmac reduces energy expenditure. That means muscle power, without interference from vibrations, can be more effectively applied to the pedals and more efficiently converted into watts.
Throughout the spring and most of the summer, we used two different types of Vittoria tyres, the Corsa N.EXT and Corsa Pro. They were fitted on a bike designed for triathlons and time-trials, the Canyon Speedmax CF SLX. These two different models of tyres were both mounted on Zipp NSW 858 wheels – with and without inner tubes. With an inner channel width of 21mm, the chosen size for both models was 28mm, the size that offers the best compromise between rolling resistance, aerodynamics, and comfort.
Corsa N.EXT and Corsa Pro differ a lot in terms of both construction and character. The former is a tyre with a silica and graphene tread, similar to all tyres in the Corsa series, but with a nylon carcass. It’s a fast-rolling but robust tyre, with excellent grip and a third layer of puncture protection, making it versatile for real-world use.
The Corsa PRO, on the other hand, is a cotton tyre designed to deliver race day performance; it’s the latest generation of a product universally considered to be the gold standard and a serial race winner, used by many WorldTour teams. Thanks to a new electric vulcanisation process that’s used to apply the thread, the new Corsa Pro is softer than the older versions, more flexible, and extremely fast-rolling. The shape of the tyre, once mounted on the rim, perfectly matches the carbon profile, offering excellent aerodynamic performance. The graphene and silica tread compound offers smoothness, durability, and excellent ground grip. And after about 3,000 kilometres of testing, both tyres remained perfect, both in terms of the tread and in the curvature of the tyre.
The main differences we noticed between the two models were all to do with the riding experience. With the Corsa Pro, the road feel was incredible. On the Speedmax, which is designed for time-trials and as such is particularly stiff, the ride was made noticeably more comfortable thanks to the 320TPI cotton carcass. Both models were smooth-rolling, but the Corsa N.EXT is a more robust tyre, suitable even for occasional use on gravel roads, and that comes slightly at the expense of comfort.
Directly comparing both tyres over a long period, on the same type of bike and on different surfaces, was an excellent way to properly understand how the riding experience is changed based on the tyre set-up chosen.
So a tip before buying a new bike: If you’re no longer satisfied with your current one, try a simple experiment and change tyres. Try mounting a new-generation cotton model like the Corsa Pro. The results will surprise you.