A close up of the new Cervélo S5: Tiesj Benoot's bike from Kuurne-Brussel-Kuurne

It appears a small contingent of riders within the Jumbo-Visma team have been racing a new bike in recent weeks. More specifically, it appears that Cervélo has a new S5 aero bike up its sleeve, and Wout Van Aert piloted it to victory at Omloop Het Nieuwsblad on Saturday. However, due to the subtleties of its changes, it had managed to fly under the radar despite being on show for all to see, until now. 

We got up close with the new bike ahead of Sunday's Kuurne-Brussel-Kuurne, which was piloted by Tiesj Benoot during both of the Opening Weekend's race days. 

The standout difference between Cervélo S5 new and old is the depth of the head tube area, and with the new design, it seems as though Cervélo has taken advantage of the UCI's relaxation of the rules that govern the permissible dimensions of tube shapes, no doubt for greater aerodynamic gain. It also appears to use a neater one-piece design than previously. 

With the S5, Cervélo was already using a novel design here that places the steerer tube on the outside of the frame, putting it in front of the head tube and shaping it in such a way that mimics a single tube with a deeper profile, but without breaking the UCI's rules. 

The design of the new head tube retains this same concept, but by deepening both the head tube and steerer tube, each tube is theoretically more aerodynamic in its own right, and in turn, should be more aero overall.

The other major difference lies in the junction between seat- and top tube. The existing design simply joins the two with a curved edge, as seen on Teunissen's bike above. The new design, meanwhile, uses a straighter edge to adjoin the two. It's a small detail, but one that's found on a number of other aero bikes such as the Merida Reacto.

Other details are even more subtle, with the seat tube, bottom-bracket shell and seat stays both appearing slightly altered, while the two-pronged aero handlebar seems to be entirely the same. Overall, it's certainly a case of evolution rather than revolution for the brand's flagship aero bike. 

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Benoot's bike was fitted with the new Shimano Dura-Ace R9200 groupset. In any normal year, this would be a given, but many teams are being forced to use the previous model or mix and match to overcome a shortage in availability. Up front, he had fitted a 54/40T chainring combination, and this is paired with a 10-30T cassette at the back. 

Wheels were also courtesy of the new Shimano groupset, with the Dura-Ace C50 hoops being wrapped in Vittoria's Corsa Graphene 2.0 tubular tyres. 

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Beneath the integrated handlebar, around 20mm of spacers are used to raise Benoot's position, while a CloseTheGap computer is mounted to hold the Belgian's Garmin computer out front. At the back, a Fizik Antares carbon saddle is Benoot's perch of preference, and it appears he's using a secondary seatpost clamp to prevent it from slipping on the rough cobbles.

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Tiesj Benoot's new Cervélo S5: Full bike specifications