The Vittoria Corsa Professional is among the greatest street bike tyres on the market, and is seen fitted to an excellent few groups’ bikes on the Tour de France and all through the season. For almost all of the season up to now, the professionals have been choosing a 28c width, pushing as much as a 30c sometimes – particularly for these nervous about hookless rim compatibility – and even 32c for races like Paris-Roubaix. However whereas on the Tour de France Grand Départ in Florence, we noticed some riders on crew Visma – Lease a Bike utilizing an unreleased 29c width of the Corsa Professional.
Are professional riders so delicate to tyre width that Vittoria felt the necessity to create a tyre that straddles the present 28c and 30c choices? Not fairly.
Tyres have, on the entire, been getting wider because the seasons go by. Free from the constraints of rim brakes, producers of each frames and wheels have been pushing the envelope and wheels are actually usually aero-optimised for 30c widths. Visma was seen working a brand new set of Reserve wheels on the Classics initially of the yr with a wider inside width, with claimed aero advantages for these races the place wider rubber known as for.
29c is a brand new width for the Corsa Professional, and is acknowledged to be designed particularly for a 25mm inside rim width, which occurs to be what the Reserve wheels that Visma makes use of are. (Picture credit score: Josh Croxton)
The sidewall of those new prototype tyres additionally states that they’re optimised for a 25mm inside width rim, and once I requested Vittoria about it the model confirmed our suspicions:
“Technically, it’s an precise 29mm on a 25mm rim, optimised by way of casing form and tread width to enhance puncture resistance and cornering security when utilizing 24-25mm rims, whereas maximising the aerodynamic profit on such broad rims.”
Typically displaying is less complicated than telling – An idealised cross-section of the identical tyre tread with completely different rim widths. Word the extra supported sidewalls on the broader rim, however the decrease most lean angle. (Picture credit score: Will Jones)
It’s no shock to listen to there are claimed aero advantages, however the point out of ‘cornering security’ is what has piqued the curiosity most within the Cyclingnews tech crew.
Two massive promoting factors of wider inside rim widths embody a much less curved lateral cross-section, which means a wider contact patch and thus higher stability in corners, in addition to a extra secure tyre sidewall beneath exhausting cornering. Because the sidewall is extra instantly atop the wall of the rim it helps to cease it from folding over, however this push to wider rims, mixed with the continued use of 28c because the nominal normal width for execs has had an unintended consequence.
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For a similar tread width, should you widen the bottom of the tyre out, you additionally scale back the lean angle required to begin cornering on the sidewall of the tyre itself. The one method round that is to make use of a wider tyre, which then begins to negate the advantages of the extra sidewall help, in addition to including weight.
I believe that this 29c width has, a minimum of partially, been developed by Vittoria on the request of Visma-Lease a Bike to allow their riders to nook more durable. I’ve put this principle to Vittoria, however I’m but to obtain a response.
There’s already proof of this occurring with a really comparable setup. Alec Briggs of British crew Tekkers runs Reserve Wheels and Corsa Professional tyres and in a latest Instagram publish, it’s clear to see simply how far off the tread of the tyres he’s been going. One commenter asks “Rims too broad for the tyre?”, to which the reply was a fairly unequivocal “Yeah, mainly”.
Increasing this thought out to UAE Workforce Emirates, we noticed Tadej Pogačar working 30c tyres within the opening levels of the Tour. It isn’t clear whether or not he’s utilizing 30c for each stage, although. The Enve rims the crew makes use of are additionally wider than the norm, and it may very well be that cornering capacity is the rationale right here, too, fairly than merely a case of aero optimisation.
Watching how exhausting the Slovenian was driving on the descent of the Col du Galibier on stage 4, it’s definitely not out of the query that it was on the forefront of the riders’ minds throughout recon rides.
