By Peter Cossins
Mesmerising when seen from above, pulsing like a school of fish as it sweeps past roundabouts and traffic islands, the peloton is the pro rider’s office, the place where they tend to spend most of their working day, a sanctuary that offers safety in numbers. While those within it still need to be watchful, the peloton is a haven, sheltering riders from their most persistent enemy – air resistance.
It has been generally assumed by sitting within the heart of the peloton a rider will reduce their air resistance by up to 50 per cent. However, a new study by Dutch scientist Bert Blocken has revealed that riding in the middle and towards the back of the bunch can mean a rider faces only five per cent of the air resistance compared to a rival who has ventured off the front on their own.
“In cycling circles, it has long been thought that being in the peloton means a rider can economise on their effort by between 50 and 70 per cent. That figure is based on old studies and small groups of riders. Our calculations have shown that if you start with a base of 100 per cent air resistance for a solo rider, the figure goes down to five per cent for the riders occupying the best places in the peloton. The gain is enormous,” Blocken told L’Équipe.
“If you relate that to the amount of power produced, the most sheltered riders are only producing enough power to ride at between 12-15kph if they were on their own. But they’re sitting within a peloton that’s racing along at 54kph…”
Working in a wind tunnel in his research department at the University of Eindhoven, Blocken set up 121 bike-mounted clay models, with the bunch in the typical arrowhead formation being 10 riders broad at its widest point. Based on this static bunch, Blocken calculated that the best places for reducing wind resistance are in the very heart and towards the back of the group. He also noted that riders at the sides of the peloton are still significantly more exposed than those in the middle of the pack.
Blocken’s study revealed that 47 per cent of riders in his peloton benefited from air resistance of between 5-10 per cent. Interestingly, the rider at the front of the bunch also had their wind resistance lowered by 14 points compared to a solo rider as a result of the momentum they received from the bunch speeding along behind them, which helps to explain why the peloton almost always reels in breakaways.
It remains to be seen whether Blocken’s findings will have any impact on the tactics employed by teams and riders within the peloton. Will, for instance, riders be advised not to ride at the sides of the bunch? Or even right at the back?
While the adoption of that second tactic is very improbable, the likelihood is that there will be plenty of interest. L’Équipe points out that Blocken has previously advised Chris Froome on the most aerodynamic position for descending – buttocks on the top tube and back aligned with the saddle rather than being slightly more upright as Froome was when he famously won the 2016 Tour stage into Luchon with an extremely rapid descent off the Col de Peyresourde. Froome adopted this Blocken-advised position when descending off the Colle de Finestre as part of a Giro d’Italia-winning performance in May.
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