Cervélo S5 (Dura-Ace Di2) frameset
The 2025 S5 picks up where the previous incarnation left off. Andy Lloyd / Our Media
The latest Cervélo S5 builds on the reputation of its predecessor, with refined aerodynamics and lighter weight without sacrificing stiffness.
The S5 is nominally a pure aero bike, but it’s also the bike most often used by the likes of Jonas Vingegaard, Wout van Aert and Matteo Jorgenson in races.
Before its launch, Vingegaard used the S5 exclusively during his general classification bid at the Criterium du Dauphiné.
The S5 is viewed as more of an all-rounder than the R5. Andy Lloyd / Our Media
It’s only when the race hits the high mountains that the team switches to the R5 (a new model of which was seen at the 2025 Tour de France, weighing only 7.03kg in a size 58cm with pedals, bike computer and empty bottles). This indicates that the S5 is considered something of an all-rounder compared to the R5’s climbing specialism.
From the side, the most noticeable changes are to the head tube and fork legs, which are now deeper than before, making more of the UCI’s latest 8:1 tube ratio regulations.
This helps to manage airflow more effectively at this key frontal area, assisted by the bayonet fork design retained from the old S5. This enables the steerer tube to be recessed further back relative to the leading edge of the head tube, increasing the effective chord length without compromising handling (more on geometry to come).
The silhouette will be familiar to fans of the previous S5. Andy Lloyd / Our Media
Also retained is the frame’s curvature around the front and rear tyres, providing a familiar overall silhouette despite the changes.
Front-on, a slimmer structure to the head tube, seat tube and seatpost is suddenly obvious, while the new cockpit’s reprofiled top bar widens the aperture relative to the old one, which is said to create less drag-inducing turbulence behind it.
Also important is the new Reserve 57/64 wheelset, which is designed to complement the S5’s asymmetric design with widened spoke angles and a new rim profile.
The 2025 S5 gets new wheels in the shape of Reserve’s 57/64 wheelset. Andy Lloyd / Our Media
All these factors add up to a 6.3-watt saving at 50kph compared to the old S5 with its Reserve 52/63 wheels, according to Cervélo.
It also says that a refinement of its carbon layup and curing processes (where it uses an inflatable bag, rather than traditional foam mandrels) led to less waste material in the frameset to the tune of around 30g.
The new HB19 cockpit is also one-piece, thanks to the removal of the bolts and hardware for the old cockpit’s topbar attachment.
This saves around 100g, but comes at the cost of the 5-degree angle adjustability the previous bolt-together layout had, and means you’ll need to swap the whole thing out if you want a different handlebar width or stem length.
The fork legs are notably deeper than on the 2023 S5. Andy Lloyd / Our Media
Cervélo has also limited the deeper fork’s weight gain to a claimed 57g, with downsized hardware at the dropout and brake caliper mount points.
Unlike the as-yet unreleased R5, it still requires the use of the caliper’s flat mount bracket, but you’re locked into using a 160mm rotor.
Overall, the frame is claimed to weigh 1,006g, and the fork 465g in a size 56cm.
Further weight savings are seen at the seatpost. This is thinner than before, but the saddle mount features a new carbon plate and alloy clamping bars, which are said to improve adjustment range (a weakness my colleague, Simon von Bromley, noted in his review of the previous version) while shedding 27g compared to the old design.
The seatpost is held in place by a wedge clamp, with a choice of 15mm and zero setback. Andy Lloyd / Our Media
The seatpost is fastened in place by a simplified wedge clamp which is covered by a simple push-on top cap.
Cervélo has even gone to the trouble of designing its own direct-mount hangers for the bike, known as éUDH.
Probably inconsequential in the grand scheme of things, this saves a single gram over SRAM’s UDH, and 5.8g versus its old Shimano hanger. The frame is also compatible with direct-mount derailleurs.
The bike uses a BBRight pressfit bottom bracket, and retains the old model’s 34mm tyre clearances.