One of the events in cycling that all right-thinking people enjoy is an Hour Record attempt. And it’s been a vintage year – we’ve seen three successful rides, starting with Ellen van Dijk breaking the women’s record in May, riding 49.254 km and putting 849 metres onto Joss Lowden’s previous mark. Then in August Dan Bigham broke the men’s record with 55.548, putting 459 metres onto Victor Campenaert’s previous distance. And in October, Filippo Ganna put a substantial 1,244 metres onto that, to bring the men’s record to an impressive 56.792 km.
There’s a pattern. Both records are now in the hands of very powerful riders – van Dijk and Ganna have more power at their disposal than almost any of their contemporaries. Both the riders whose records got broken, Lowden and Bigham, were working off a lot less wattage, but better aerodynamics.
It was more stark with Bigham and Ganna. The contrast was emphasised by the fact that Bigham was the performance engineer for Ganna’s ride, and his own record was substantially a technology-proving run for the Italian’s.
To put some numbers on this – we know Bigham’s CdA (that’s his aerodynamic drag) was 0.155 m2. This is astonishingly low for a 75kg rider. On that basis, he set his record with around 350 watts. In terms of raw grunt this is not really all that much for an elite male athlete of Bigham’s size. (It’s about 4.6 W/kg, if you’re a Zwift fan.)
The fact that so much of Bigham and Ganna’s technology was shared, and the fact that Ganna has previously posted power numbers from time trials on social media, means we can make a pretty reliable guess that Ganna’s CdA was 0.185 m2 or thereabouts and his power output when he broke the record was about 440 watts.
What’s interesting from the perspective of our power-rider versus aero-rider question is that to ride the same distance as Bigham, Ganna would have needed 415 watts. Now, he’s a bit bigger (around 83 kg) but that’s still a lot more grunt – about 5 W/kg.
What we have here is as neat an example of the two extremes of contrasting-ways-to-go-fast as we’re likely to get. Would you prefer to ride for an hour at 415 W or 350 W? I know which I’d rather do.
There’s a “but”, of course, which is that getting a CdA as low as Bigham’s is very, very difficult. It’s not a case of a couple of wind tunnel sessions and a good helmet. Bigham has been working harder on his aerodynamics for the last 4-5 years than probably any other rider in the world. That’s been run after run on the track, hours in the tunnel, days perfecting skinsuit designs and sourcing or making the best components that work for you. It’s not necessarily easier to get your CdA from 0.185 m2 to 0.155 m2 than it is to get your power output from 350 W to 415 W.
What is different about the two sides of the equation is measuring them. Nearly all serious riders have power meters – they know their numbers, how they’re affected by form, by conditions, by freshness. There probably hasn’t been an hour record attempt in twenty years that didn’t start with working out a rider’s critical power.
Aerodynamic drag is harder to deal with this way. It’s harder to measure. It’s the aim of Body Rocket to change that and give you access to the other half of the equation that is as simple as your power numbers. If you’ve got both the power and the drag you’re in a position to work out where the sweet spot is.
If you’re attacking the Hour, there’s another advantage to making CdA another number you have access to all the time, rather than something you find out once a year in track or tunnel testing. When I was helping Alex Dowsett with his 2021 Hour attempt, one of the things we didn’t know and had no easy way of finding out was how fatigue affected his position on the bike, and what any changes would do to his drag.
He fell away from the pace at around 40 minutes, partly because his power dropped, but at least as much because fatigue meant he struggled to hold the position. If we’d had an accurate number on that from his road riding we’d have been able to plan for the difficult bits of the ride from an aerodynamic point of view as well as a physiological one.
And of course all of this applies to time trials, triathlons, long-range road race attacks… The Hour Record has always been a laboratory to explore the edges of what’s possible. Whoever holds it and however they did it, it’s a great idea to pay attention.