Wout van Aert won a cyclo-cross race on a gravel bike

Wout van Aert won his first cyclo-cross race of the Christmas period on Wednesday, and the secret weapon was a gravel bike.

In a striking change from his usual ‘cross set-up, the Belgian rider switched to Cervélo’s dedicated gravel bike, the Aspero, for the race in Heusden Zolder, and it was clearly up to the job.

The Aspero – which Van Aert rode at the 2023 UCI Gravel World Championships – is not a million miles away from Van Aert’s customary cyclo-cross racing machine, the R5-CX, which itself draws from Cervélo’s top-end road climbing bike, the R5.

• Read more: Wout van Aert's Cervélo Aspero for Gravel World Championships

However, there are some significant differences. Whereas the R5-CX features narrow seat stays that join at the seat tube-top tube junction, the Aspero has wider stays that attach lower on the seat tube, which itself is rounded to hug the rear wheel. This bears more similarity to the Cervélo’s aero road bike, the S5, and the Aspero also features a thicker fork than the R5-CX, although nothing like the S5.

© Velo Collection (TDW) / Getty Images

A closer look at Wout van Aert's Cervélo Aspero for Heusden-Zolder

The Aspero can accommodate tyres of up to 40mm, but there is no specified tyre clearance for the R5-CX, beyond the need to avoid mud clogging around the UCI maximum of 33mm tyres for ‘cross racing.

In terms of geometry, the Aspero has a longer reach than the R5-CX, although the stack height is in turn increased, along with 20mm more head tube length. Geometry for gravel bikes tends to put the rider in a more relaxed position than on racier 'cross bikes.

With shorter seat stays and chain stays, there’s only a 2mm difference in the wheelbase. However, there's a significant increase in the bottom bracket drop on the Aspero, giving it a lower centre of gravity and increased stability.

© Velo Collection (TDW) / Getty Images

For comparison, here's Van Aert on his R5-CX the previous weekend

Wout van Aert has not stated why he chose to use his gravel bike in an elite cyclo-cross race, and Cervélo hasn’t made any noise about it. The course in Heusden-Zolder was a fast one, which was perhaps what tempted Van Aert into using a bike designed for longer periods of higher speed, even if there will have been a slight weight penalty.

In any case, the fact that a gravel bike has now won a cyclo-cross race further blurs the boundaries between the disciplines, which was one of our Top 10 tech takeaways from 2023.

© Velo Collection (TDW) / Getty Images

Wout van Aert crosses the line for victory in Heusden-Zolder aboard his gravel bike