Tadej Pogačar won the 2025 Tour de France using, almost exclusively, an aero bike. Second-place finisher Jonas Vingegaard chose Cervélo’s aero bike, the S5, for every single road stage of the race.
Despite having super-lightweight bikes available, pro cyclists are favouring their sponsors' aero bikes, even on mountainous stages.
Why is this? How much difference does it make? What does it mean for pro cycling? Should we all throw our lightweight bikes in the bin?
What’s going on?
Tadej Pogačar won four stages of this year’s race. Aside from stage 4 into Rouen – a lumpy stage with a draggy uphill sprint finish – his other wins were all uphill finishes, in Mûr-de-Bretagne, up the Hautacam, and the mountain time trial up Peyragudes.
For all of these stages, Pogačar used the Colnago Y1Rs – an unashamed, no-holds-barred, flat-out aero bike.
We know he had a lightweight Colnago V5Rs available to him, which can easily hit the 6.8kg UCI weight limit, but instead favoured the heavier (we weighed his standard Y1Rs build at just over 7.5kg) model for pretty much every stage of the race.
We saw UAE Emirates-XRG wheel out a special black frameset stripped of the pearlescent white paint for the mountain time trial (which Pogačar also ran with lighter wheels and no bar tape to save even more weight).
Although he used this bike for the rest of the race in the brutal, mountainous third week, it would likely still have been a few hundred grams heavier than his V5Rs, owing to the deeper tubes and more aerodynamic cockpit.
‘But Pogačar could win on any bike!’
But it wasn’t only Pogačar who stuck to an aero bike. Let’s face it, he’s the best bike rider in the world – maybe even of all time – and he could probably win on a Brompton.
Vingegaard used Cervélo’s S5 for every road stage. We weighed his 51cm bike at the Grand Depart in Lille at 7.3kg with a 1x drivetrain, deep-section Reserve wheels, a bike computer and empty bidons.
Vingegaard used a variety of wheel depths and drivetrains throughout the race, so the weight was probably a touch lighter in the mountains.
But, given that the new Cervélo R5 Matteo Jorgenson chose to use on a few stages weighed in at only 7.03kg in a size 58 (again with a computer and empty bidons), a 51cm-framed R5 would almost certainly be lighter than the S5 Vingegaard was riding.
The Dane didn’t win a stage this year, and was bettered by Pogacar on all but one of the uphill finishes.
However, his Visma-Lease a Bike teammate, Simon Yates, won the very hilly stage 10, which included eight categorised climbs and finished up the second-category Mont-Dore. Yates’ bike of choice for a tough stage that included 4,450m of elevation? The S5.
How much difference does it make?
How much difference does an aero bike make versus a climbing bike? Let’s use stage 18 of the 2025 Tour de France as an example.
At 171.5km, from Vif to Courchevel through the French Alps with a total of 5,450m of elevation, the stage included three brutal HC climbs – the Col du Glandon, the Col de la Madeleine, and a summit finish up the fearsome Col de la Loze.
The winner of this stage, Ben O’Connor, piloted an aero Giant Propel to victory after attacking at the bottom of the final climb and riding solo to the finish.
O’Connor’s average speed for the stage was 33.87kph. According to Strava, up the nearly 26km Col de La Loze, which O’Connor rode solo, he averaged 22.5kph.
At that speed, aerodynamic performance isn’t going to be much of a factor at all – with most brands agreeing that aerodynamics come into play at speeds faster than about 25kph, and most aero optimised products being designed around racing speeds of 40-50kph.
Colnago, for example, says that “Tests conducted in real-world configurations show that the Y1Rs requires 20 fewer watts than the V4Rs to maintain a speed of 50kph. [This confers] A significant advantage in fast races and windy conditions.”
However, using an online power & speed calculator, we can see the power difference required on a lightweight bike setup versus an aero bike.
| Rider weight | 67kg | 67kg |
| Bike weight | 7kg | 7.5kg |
| Gradient | 6.5% | 6.5% |
| Speed | 22.5kph | 22.5kph |
| Watts required | 373.05 | 375.04 |
With all the other variables remaining the same, including CDA and rolling resistance, a 500g difference in bike weight – which is arguably generous when comparing aero and lightweight bikes in 2025 – results in a difference of just under two watts.
So why are pros choosing aero bikes over lightweight climbing bikes?
Two watts isn’t that big a difference over an hour or so, and that number also doesn’t account for any aerodynamic benefit of the aero frame over the lightweight climbing frame. On the faster sections of the climb, where O'Connor's speed increased to in excess of 50kph, the weight difference would be more than offset by the aerodynamic gains.
This also doesn’t factor in the energy O'Connor managed to save for the 145km before the final climb – not to mention the 17 stages that came prior.
Bike racing is only getting faster. This year’s Tour was won with an average speed of 42.8491kph across 21 days of racing – that’s a new record by 0.7kph.
Riding bikes fast gets exponentially harder the faster you go, as the power required to overcome drag increases at the cube of velocity – the jump from 30kph to 40kph is demonstrably easier than the jump from 40kph to 50kph, despite both being an increase in speed of 10kph.
Racing hundreds of kilometres every day for three weeks burns an absolute shedload of energy – so if a rider can save even a little bit every day, this stacks up to race-winning differences when the racing really kicks off.
What does that mean for the pros?
The lightweight race bike is dead in the pro peloton.
If the UCI weight limit stays at 6.8kg, and modern aero bikes can be built pretty close to that, why would you want to ride a climbing bike that weighs pretty much the same, but is less efficient?
While a lighter bike will be faster than a heavier bike on an isolated climb, professional bike races like that simply don’t exist.
Even the stage 13 mountain time trial up Peyragudes at this year’s Tour de France had a 3km flat section at the start, where riders were cruising at 50kph.
Simply put, pro bike racing is so fast now that there isn’t a parcours out there hilly enough to justify prioritising weight saving over watt saving.
On top of that, if the UCI weight limit stays at 6.8kg – even though we’ve seen most of the bike manufacturers at the Tour build aero bikes up that are close to that – then what incentive is there to choose a lightweight bike in the first place?
But what about us?
Fortunately, for amateurs, consumers and the general cycling masses, you don’t have to race the Tour de France. You can choose a bike based on heaps of other features beyond ‘what’s fastest?’.
Things such as fit, aesthetics, ride feel, colour and budget will have a much bigger input on the bike you choose to ride, beyond pure speed.
But, for the pros, outside of a very select few stages and keeping sponsors happy, the days of the dedicated climbing bike are over.
