One of the hottest debates in the professional road cycling season this year has been bike choice. Should pro cyclists ride a lightweight climbing bike or an aero bike?
Tadej Pogačar and Jonas Vingegaard rode aero bikes for practically every stage of the men’s Tour de France, with the former winning the race on the Colnago Y1Rs and the latter coming second on the Cervélo S5. And this was after Simon Yates smashed the Col de Finestre record using Cervélo’s aero bike to win the 2025 Giro d’Italia.
The 2025 season is a turning point – many aero bikes are now light enough that riders, such as Pogačar, Vingegaard and Yates, are choosing to ride them even in high mountain stages. In fact, after the 2025 Tour de France, I argued that the lightweight climbing bike is dead.
Yet the Tour de France Femmes avec Zwift painted a different picture. Pauline Ferrand-Prévot won two stages and the maillot jaune using the lightweight Cervélo R5. Breakout star Maëva Squiban of UAE Team ADQ also won a pair of stages on Colnago’s lightweight V5Rs. Of the race's nine stages, only the first was won on an out-and-out aero bike, a Cervélo S5 piloted by the legendary Marianne Vos.
Of course, plenty of teams race bikes that are ‘all-rounders’. The Specialized S-Works Tarmac SL8, Pinarello Dogma F and Trek Madone all purport to be a one-bike-fits-all solution, balancing lightweight and aerodynamic qualities.
But out of the teams that use bikes from brands that produce a climbing bike and an aero bike, a question lingers: Why have the men’s peloton completely eschewed the lightweight bike in favour of aero bikes, and why haven’t the women’s bunch followed suit?
The race speed is high enough
“Women are riding plenty fast enough to make use of the aerodynamic advantage of a more aero frame or aero equipment,” says Dr. Xavier Disley, performance analysis consultant and the owner of AeroCoach, a UK company devoted to improving the speed of cyclists.
“The average speed for the women’s Tour de France in 2025 was 39.1kph, with the men’s at 43.4kph” – making it the fastest ever Tour de France – “which means that for a given change in aerodynamic drag, let’s say 0.005m2, the women would save ~5w at that speed compared with the men who would save ~7w, so the aero savings are very comparable,” he explained in an email.
So, if the speed is high enough, why are riders in the women’s bunch not prioritising aerodynamics as readily as the men?
Jenco Drost, head of performance equipment at Team Visma – Lease a Bike, says each rider is equipped with the optimal bike and wheelset for their unique role, ensuring “maximum efficiency and comfort”.
“By analysing altitude gain, the positioning of climbs within the stage, and the steepness of every ascent, we’ll determine whether the aero-focused S5 or the lightweight climbing R5 offers the greatest advantage,” says Drost.
A question of height
Alongside altitude gain and the position and gradient of climbs, there is one less complicated factor in choosing an aero or climbing bike: the rider’s height.
According to ProCyclingStats, the 2025 Visma Lease-A-Bike teams at the men’s and women’s Tours de France average 1.8275m and 1.694m, respectively. Cervélo’s own size guide would suggest that the men’s team use a 56cm frame on average, and the women’s team use a 51cm frame.
“Different frame sizes mean different weights, which can shift the balance between climbing speed and aerodynamic gains – so the best choice may vary from rider to rider,” says Drost.
The weight difference between aero bikes and climbing bikes can be significant, especially when every detail of a pro’s bike is obsessed over.
At the Tour de France Grand Depart in Lille, we weighed Jonas Vingegaard’s 51cm S5 at 7.385kg and Matteo Jorgenson’s 58cm Cervélo R5 at 7.03kg. That means Jorgenson’s climbing bike was over 350g lighter than Vingegaard’s aero bike, despite being three sizes larger.
But Disley says: “Weight penalty is not something to worry about. It’s tiny in the grand scheme of things and the aero bikes these days are within 200-300g frameset weight compared with the lightweight ones.”
The UCI weight limit is ‘completely outdated’
While Disley sees weight penalty as something not to worry about, AG Insurance – Soudal Team’s Ashleigh Moolman-Pasio has a different view.
With a career spanning 18 years and a background in engineering, she finds the UCI’s minimum weight limit of 6.8kg “completely outdated”.
The origin of the 6.8kg minimum weight, which was introduced in 2000, is unclear, but Moolman-Pasio suspects its roots lie in the men's peloton.
“Back then, I’d guess the average weight of a male professional cyclist was around 68 kg, and someone decided the bike should weigh roughly 10 per cent of that – 6.8 kg. Perhaps there was a little more analysis behind it, but the principle seems that simple,” she says.
According to Moolman-Pasio, this minimum weight disadvantages lighter riders because bike weight forms a higher percentage of their total system weight (a rider, their bike and any other kit).
“Take a climb like the Col de la Madeleine (18km at 8 per cent),” says Moolman-Pasio.
“A 52kg rider putting out 5.5 W/kg will climb it at about 14.3kph. A 60kg rider with the same relative power climbs at 14.8kph – 1 minute and 16 seconds faster. Why? Because the heavier rider’s system power-to-weight is higher, since the fixed bike mass is a smaller portion of their total weight.”
Assuming for a second that all bikes raced in the pro peloton weighed 6.8kg, the disadvantage to lighter riders is clear. For a 78kg rider, a realistic average for a larger rouleur or sprinter in the men’s peloton, 6.8kg represents 8.71 per cent of the rider’s weight. For a lighter rider of 58kg, this weight is 11.72 per cent.
If we follow Moolman-Pasio’s logic, then lighter riders should be more discerning in choosing frames and components that save them weight.
Fit and feel
Fit and ride feel have a massive effect on bike choice – and this is often more tangible than a bike's weight.
Moolman-Pasio says: “Ideally, your bike should feel like an extension of your body. If it’s too stiff, it resists the natural movement and rhythm you have when climbing, especially out of the saddle. That resistance costs energy and reduces efficiency over a long climb.”
“These are the main reasons why smaller riders – often without even consciously breaking it down – will tend to choose climbing bikes and lower-profile wheels on mountain stages. They might just say, ‘This setup feels better for me,’” she adds.
There is also the question of simply getting a bike to fit you. “The integrated nature of some of the more aero bikes makes it more tricky to adjust for women,” says Disley.
“As an example the Y1RS doesn’t have the same amount of adjustment as an S5 in terms of its cockpit (handlebar minimum width and minimum stem length, or longer stem with narrower bars).”
Available frame sizes can be an issue, too. The Colnago Y1RS is only available in four sizes, whereas the V5Rs is available in seven sizes. At 1.66m, Maëva Squiban would be riding a 45.5cm V5Rs and – given the Y1RS range stops with a small frame – might not even fit on the aero bike.
The parity in sizing across Cervélo’s range of bikes is better. The S5 and R5 are available in six frame sizes from 48cm to 61cm. “When the difference between S5 and R5 is really small, the final call rests with the rider,” says Drost.
“After all, confidence and comfort on the bike are just as crucial as the numbers,” he adds.
