The cyclocross season is now under way and Cervélo has released the R5-CX. Cervélo says the bike was designed specifically for Team Jumbo-Visma riders Marianne Vos and Wout Van Aert, who hold 10 cyclocross world championship titles between them.
The R5-CX is currently only available to the pros, but it will be released to the general public next summer, making it Cervélo’s first production cyclocross bike.
While Cervélo says it draws much inspiration from the Cervélo R5 road bike, this new cyclocross bike has a number of key differences thanks to Vos and Van Aert’s input.
The bike has a threaded bottom bracket, which is unusual for Cervélo, alongside a double seatpost clamp and plenty of tyre clearance. The geometry of the bike makes some concessions to cyclocross. It retains the same reach as the R5 road bike, but has a lower stack height.
If you are particularly eagle-eyed, you may have spotted the Cervélo R5-CX being raced by Vos on the North American World Cup scene last month, where she won at Waterloo and Iowa.
Threaded bottom bracket
The R5-CX has a threaded bottom bracket. This is notable for Cervélo, which has long stuck to its BBRight press-fit bottom bracket.
The switch makes sense because cyclocross bikes are exposed to an awful lot of muck and grime, frequent washing and regular strip downs – all things that aren’t particularly favourable with a press-fit bottom bracket.
However, things aren’t so straightforward. Cervélo has kept the asymmetric cup design on BBRight and opted for T47 threads. It uses an inboard cup on the left-hand side and an outboard cup on the right-hand side.
This might be okay for the pros, but it might cause bottom-bracket buying headaches – as if we needed more of those – once the bike is released to us mere mortals next year.
The bottom bracket on the R5-CX is 11mm higher than on the R5 road bike to create greater clearance over obstacles.
D-shaped seatpost and double clamp
The R5-CX gets the same D-shaped seatpost as the R5.
The engineers at Cervélo say the R5-CX was originally going to have a standard round seatpost, as on the brand’s Áspero gravel bike, but the D-shaped seatpost was requested by Vos and Van Aert. Presumably, this is because they are familiar and get on well with the D-shaped design on the R5 road bike.
Another request from the two Jumbo-Visma riders was a double seatpost clamp. Cervélo says this is to “keep the saddle facing forward in case of a crash”, which seems an odd statement considering a D-shaped seatpost won’t rotate like a round one.
A more understandable reason for the extra clamp mounted on the post is to ensure you get exactly the right saddle height after removing the post. Saddle height also isn't affected by the heavy bumps the riders are likely to put through the saddle during a race, for example when riding over rough ground or after less-than-perfect remounts.
Pro spec
The R5-CX is compatible with electronic drivetrains only and cable routing is internal, which Cervélo says is to minimise water ingress.
The bike we have seen is fitted with a top-of-the-line Shimano Dura-Ace Di2 R9200 groupset and wheels.
For UCI-sanctioned cyclocross events, the maximum tyre size is 33mm, and this is what has been fitted to the R5-CX we have seen. The frame is said to have ample clearance to help shed mud and could likely take much larger tyres, but choosing to maximise that clearance with a bigger tyre size may affect the R5-CX’s handling geometry.
Not the first cyclocross bike
It’s worth noting that while the R5-CX will be the first Cervélo production cyclocross bike, it’s not the first 'cross bike the Canadian brand has made.
That honour goes to the R3 made for Jonathan Page in 2007, which he rode to victory as the first American to win a cyclocross world cup podium.
