Speed is in the Details
Can changing handlebar height by 10 mm put you closer to the yellow jersey? How much faster will a couple of degrees more mobility in your hips make you? How many watts do you gain, by tucking in your shoulders to get into your most aggressive position? Once you’ve found the best CDA for a bike and its rider, is there a secret to making it last for the entirety of a time trial at the end of a three-week tour?
It’s complicated. But it all starts with a readiness to collaborate.
As Stifu Christ, BMC’s Head of R&D walks across the road towards the Tissot Velodrome and the expectant AG2R CITROËN Team, he’s ready to reflect and collect yet more data from one bike and one world-class team of cyclists. A whole group of experts have gathered on site to harness technology, to evaluate and experiment, with the collective goal of optimisation and improvement. Welcome to the world of racing for Grand Tour victories, at the cutting edge of cycling.
“This year, I’ve found myself in a different position; the game is now there to play. It’s like suddenly jumping into the premier league final when you didn’t really expect it. It’s a little bit mad, but this is what being a pro athlete is all about.” – Ben O’Connor, AG2R CITROËN Team Rider
As cycling fans, we’ve all seen it, but may not have noticed the significance of what is unfolding during that critical final push. Two closely matched favourites go head-to-head at a key time trial after 20 days of racing. As one rider motors down the road, robotically locked into position, the other is seemingly all over the bike, hauling their body like they are giving everything, but the splits show the opposite.
That’s fatigue stepping in, causing their position to fall apart. Because a Grand Tour can be won or lost by split seconds – and, if you didn’t know already, those split seconds could be saved by a few millimetres in your cockpit, a couple of degrees more motion in your hip flexors - a few more kilometres spent practising the position.
The more extreme range of motion that time trialling demands is something a rider has to habituate themself to. That’s why AG2R Citroën travelled to the Tissot Velodrome to collaborate with the best minds in the industry on how to make sure their top riders stay optimized, even when they are hugely fatigued.
Over two 10-hour days of testing, Ben, Aurelian, Dorian, Nans, Clément and Clément from AG2R CITROËN Team are directed back and forth between the Siberian spruce wood track and a trainer - to check, test and refine their positions. They are stickered up for data collection with two inertial measuring units (IMUs) on the torso and sacrum, plus sensors to measure speed, power, and cadence.
The track has been turned into a laboratory of sorts, with trackside computers calculating live CDA values. That’s the coefficient of drag x frontal surface area - essentially evaluating how aero the rider is – as defined by the track’s geometry, the air density, the rider’s speed, wheel circumference, and current power output.
There’s one of Gebiomized’s signature pressure sensors on their saddle and one inside their shoes. “Our approach integrates the stability of the rider – which equates to their comfort – with aerodynamics,” explains Daniel Schade, founder and CEO of Gebiomized - the bike fit specialists that so many in the WorldTour have come to rely on. “Aggressive positions often work for the first 15-20 minutes of a race, but you lose a lot when instability enters the scene. With the rider being the biggest frontal area for drag, the biggest gain is to improve the rider’s position – but what’s crucial here is locking in a position that can be held over a longer time.”
It translates into a position that’s not only fast, but above all maintainable.
And so much of the maintainability comes from a rider’s biomechanics. Flexibility is put under the microscope, as they’re checked for imbalances, before moving to the trainer to see how this is reflected in their position.
“By doing these tests, we can ascertain the biomechanical potential for improvement, or where the individual may have anatomical limitations. That’s what we then build a position around. Where there’s room for potential, we’ll give them homework. The biggest question is whether the road to adaptation is long, short, or even unattainable due to anatomy,” explains Jan Neuhaus, the resident biomechanic.
Other than anatomy preventing aggressive positions, Stifu Christ reminds us there are other restricting factors at play: “Bike fitters are regulated by UCI rules – everyone works at the limit of what’s permitted; they can basically go up and down.”
Responsible for our fastest designs, this veteran bike developer knows exactly where BMC’s attention needs to be directed to create speed:
“Time trials are the pinnacle and there is a lot that’s very particular to riding bikes at high speed.”
The more adjustable a BMC bike is, the better. It’s about educating mechanics on features. It’s not just a question of forcing a rider into an aero position.
Stifu agrees: “It comes down to their confidence in the handling, which is where we invest our focus. With average speeds on the flat touching 60 km/h, if you have a heavy sidewind in those conditions, many riders struggle to hold their positions due to uncertainty. So, we’re doing everything we can to make them feel more confident in their aero position.”
As today’s collaboration is all about laying the groundwork for speed and applying some fresh thinking to render a rider’s CDA more sustainable, Gebiomized are happy to be in Grenchen and involved in the AG2R CITROËN Team project: “What we’re seeing is a bike company that really cares about how they can make the bike more adjustable; how they can help bike fitters build more custom positions – how to make riders more comfortable and ultimately faster.”
As Daniel and his team focus on the biomechanics and aerodynamics to lay out the optimal position, it is a bike brand’s willingness (and a rider’s openness) for adjustability that means everyone can concentrate on the same goal. No two riders are the same, as Daniel reiterates: “It is a really big step forward for a bike company to say, ‘it’s important that my cockpit is adjustable and that my TT bike offers a lot of possibilities,’ so that people like us can build these kinds of positions to help the individual riders.”
With a coming together of minds and technologies, the pro riders leave the Tissot Velodrome and BMC HQ better equipped, optimized and – crucially – faster. Speed really is in the details and AG2R CITROËN Team is ready for another intense season of racing.
Geek out some more on what went down at the Tissot Velodrome and be sure to listen to our latest podcast, linked below.