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more than a tire: GravelBikes.Online


This article has been produced in collaboration with Vittoria

Towards the end of his career, the great time trial specialist Tony Martin gave an interview that offered an interesting insight into his chosen discipline. Training, opined the German, will only get you so far. To be successful you also need to work on your equipment, your position, the distribution of efforts, the incorporation of new technologies. These were the areas where real gains were made.

There is no doubt that the TTs are a unique proposition. The rider is exposed to the wind all the time, without the advantage of sliding other racers, which makes it totally different from a normal road race. And no rider, let alone at the WorldTour level, can win a time trial based on talent alone. Time trials are a solo effort, but they are won through teamwork behind the scenes.

Behind every TT win is a massive collective effort, a bit like Formula 1. And like F1, the technology that makes that TT win possible ends up, in various ways, in the real world and on bikes that we drive the rest. While a team’s innovation or technical development may not be good news for their competitors, it’s great for the fans, because sooner or later we’ll benefit from all that team development and technological research.

When it comes to tires, a lot has changed recently. So in an attempt to better understand the quality and characteristics of these next-generation tires, we teamed up with Vittoria to explore how much the cycling experience can change simply by using different tyres.

Beyond the limits

“Marginal gains” is a term we are all familiar with these days. Once the athlete has reached the theoretical limit of performance through training, gains must be sought through equipment choice 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 larger tires. The benefits in both performance and comfort are significant, and it’s easy to see how a larger tire used at a lower pressure can absorb road roughness and imperfections more efficiently, thereby reducing fatigue.

In addition, thanks to the larger contact area, it reduces rolling resistance and improves braking, not to mention cornering grip.

Wide tires and low pressure

To anyone who has been riding for a long time, the principle might seem counterintuitive, because for years the prevailing wisdom was that skinny tires pumped up to high pressures were the fastest. In our heads, it feels like a skinny tire that provides a stiff interface between the ground and the rim would ensure faster speeds with the same pedaling force. But in reality this is only true on perfectly smooth and homogeneous surfaces like a velodrome track, which is why track cycling tires have remained largely unchanged.

There are at least three reasons why a larger tire provides better performance on real-world roads. First, the friction or rolling resistance is lower. Drag is also lower, thanks to a smoother rim/tire profile and better overall wheel shape. Finally, as the wheel rolls more smoothly on the asphalt, suspending the rider from the ground and isolating him from further vibrations, it also improves the contractile capacity of his muscles. And because of this decrease in vibrational stress, fatigue is also reduced. Essentially, using low pressure inflated tires on rough asphalt reduces energy expenditure. This means that muscle power, without interference from vibrations, can be applied more effectively to the pedals and converted to watts more efficiently.

Road feel

During the spring and most of the summer, we used two different types of Vittoria tires, the Corsa N.EXT and the Corsa Pro. They were riding a bike designed for triathlons and time trials, the Canyon Speedmax CF SLX. These two different tire models were mounted on Zipp NSW 858 wheels, with and without inner tubes. With an inner channel width of 21mm, the size chosen 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 greatly in both construction and character. The first is a tire with a silica and graphene tread, similar to all Corsa series tires, but with a nylon casing. It’s a fast-rolling yet robust tire 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 tire designed for race day performance; is the latest generation of a product universally regarded as the gold standard and a serial race winner, used by many WorldTour teams. Thanks to a new electric vulcanization process used to apply the thread, the new Corsa Pro is softer than previous versions, more flexible and extremely fast rolling. The shape of the tire, once mounted on the rim, perfectly matches the carbon profile, offering excellent aerodynamic performance. The tread compound of graphene and silica offers softness, durability and excellent grip on the ground. And after about 3,000 kilometers of testing, both tires remained perfect, both in terms of tread and tire camber.

The main differences we noticed between the two models had to do with the driving 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 shell. Both models were smooth-rolling, but the Corsa N.EXT is a more robust tire, suitable even for occasional use on gravel roads, and this is somewhat at the expense of comfort.

Directly comparing both tires 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 changes depending on the chosen tire configuration.

So, a tip before you buy a new bike: If you’re no longer happy with your current one, do a simple experiment and change your tires. Try riding a new generation cotton model like the Corsa Pro. The results will surprise you.

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