Cervélo claims its new Áspero-5 is the world's fastest gravel bike

As the gravel racing scene continues to grow up and speed up, Cervélo has looked to its range of road bikes for inspiration and aerodynamic advances when developing the all new Áspero-5. If the bike's silhouette looks familiar, it's because it borrows heavily from the road going S5.

With the new bike, Cervélo aimed to produce "fastest aero gravel bike", with their own test data producing claims that it is 37 watts faster than the outgoing bike, and 32 watts faster than the closest competitor, the Ridley Kanzo.

The new model has been designed in response to the evolving gravel race scene, which is faster and more competitive than ever before. The result, Cervélo says, is the “most aerodynamic gravel bike ever created.”

To achieve this goal, while also reducing weight and maintaining the stiffness of the existing model, Cervélo looked to the road for inspiration. To be more precise, to its S5 aero bike. The TT angle is the same as the S5, and the deep bb and seat gussets, are shared almost exactly in terms of the internal silhouette of the frame.

The S5 is a proven winner at the WorldTour level and it's easy to see the similarities between the bike that won two Tour de France titles and the new look Áspero-5. The frames share plenty, most notably the sloping top tube, the wheel cutout, the deep bottom bracket and the head tube shape. For the Áspero-5 it means a frameset with an increased surface area while still managing to shed 66 grams compared to the outgoing model. A closer inspection shows that much of this saving is gained via the updated brake mount on the fork.

Certainly compared to the outgoing model, the tube shapes are deeper. But it’s not the only change. The traditional round seat post and clamp has been replaced by an integrated D-shape post, that again more closely resembles the S5 aero bike.

Today manufacturers tend to make aerodynamic improvements by viewing the bike as a whole, rather than just focuing solely on the frame design. Cervélo it appears would concur, creating the HB16 handlebars to work in conjunction with the frameset. They allow for fully and semi internal cabling and pair a 40cm hood measurement with 46cm at the drops. However, they aren’t a one-piece design, which Cervélo says is to allow riders to customize their set-up with ease.

Together it all adds up to a bike that’s apparently 37 watts faster than the previous model, and, Cervélo says, 10 watts faster than Ridley Kanzo, the bike's nearest competitor. Mariana Vos has already won aboard the Áspero-5, and while her victory at the UCI race in Aachen, Germany is surely more a case of the archer not the arrow, it nonetheless underscores the bike’s racing credentials at the highest level.

So not to spoil all those hard earned savings, Cervélo has equipped the Áspero-5 with some downtube storage, which it says is the most aerodynamically enhanced solution out there.

Even the bike’s increased tyre clearance has aerodynamic implications. It now stands at 45mm with 6mm to spare each side. This allows users to either mix or match their tyre widths depending on the nature of the course. Cervélo suggests that 42mm (or matched sizes) front and rear delivers the stability needed for rougher terrain. In effect this slackens the head and seat tube angles. A mixed set-up of, say, 40mm at the front and 44mm at the rear, steepens these angles, which in turn increases aerodynamics and sharpens handling for less tricky, and thus faster, courses; Cervélo says it’s optimised the Áspero-5’s geometry around a 4mm width differential.

Given this is a gravel race bike, Cervélo has made sure that the greater tyre clearance hasn’t impacted the ability to run larger chainrings. It says the Áspero-5 is compatible with chainrings as big as 52t.

A summary of the bike’s geometry for a size 56 with matched tyres shows a stack height of 575mm and a reach of 395mm. The chainstays measure 422.5 and the BB drop is 80mm to aid stability; Cervélo says the geometry mirrors that of the Soloist, its ‘do it all’ road bike.

When equipped with mixed tyres with a 4mm difference those stack and reach numbers are adjusted to 572mm and 399mm respeactively. The head tube angle steepens from 71.6 degrees to 72, while the seat tube angle also increase by .4 to 73.

Cervélo has equipped the Áspero-5 with both a T47A threaded bottom bracket and a UDH; both are now as close to accepted ‘standards’ as the industry has had in some time.

The Áspero-5 is offered in three builds as well as frameset only option. The range topper features a Sram Red AXS groupset with a Quarq power meter and a set of Reserve 40/44G carbon wheels. There’s also a Sram Force AXS and Shimano GRX Di2 equipped models, Both feature the same Reserve wheelset and all the bikes use the new HB16/ST31 handlebar and stem combination.

Prices are as follows:

Áspero-5 Red AXS - $12,500 / £10,000
Áspero-5 Force AXS - $8,700 / £8,000
Áspero-5 GRX Di2 - $8,700 / £8,000
Áspero-5 frameset - $5,500 / £5,000