Cervélo only officially revealed their new carbon ZFS-5 full-suspension cross-country race mountain bike a few days ago, and they’ve already shown how the Jumbo-Visma team used a rigid LinkLock to convert it back to a hardtail! Unbolt the short link, remove the standard RockShox SIDLuxe Ultimate shock & its remote, then bolt in a peculiar wishbone strut in its place.
But why?
Cervélo LinkLock converts XCO ZFS fully into an XCC hardtail
![Cervelo ZFS-5 LinkLock prototype lockout gadget, XCO full-suspension to XCC hardtail conversion, Milan Vader racing](https://bikerumor.com/wp-content/uploads/2023/05/Cervelo-ZFS-5-LinkLock-prototype-lockout-gadget_XCO-full-suspension-to-XCC-hardtail-conversion_World-Cup-Short-Tack-race-800x533.jpg)
The “why” is “because UCI“.
The governing body of pro mountain bike racing, the UCI MTB World Cup rules require that cross-country racers must compete in the XCC short track race on the same bike as they ride in the main event Olympic-distance XCO cross-country race. But a closer look at the rules actually only specifies that it must be the same frame.
Individual components – like those that can be removed or replaced on the frame… for example wheels, tires, and gearing – are allowed to be swapped out to adapt the bike to the shorter, faster, and less technical nature of the short-track circuit racing. So while some racers would simply lock out their rear shock for the duration of the half hour XCC race – why not take it to the next level.
![Cervelo ZFS-5 LinkLock prototype lockout gadget, XCO full-suspension to XCC hardtail conversion, with or without rear suspension](https://bikerumor.com/wp-content/uploads/2023/05/Cervelo-ZFS-5-LinkLock-prototype-lockout-gadget_XCO-full-suspension-to-XCC-hardtail-conversion_with-or-without-suspension-800x450.jpg)
So, Cervélo engineers worked with the Jumbo-Visma team to devise a rigid shock replacement for their new ZFS-5 fully… a link to lock out the frame… a LinkLock.
Tech Detail
![Cervelo ZFS-5 LinkLock prototype lockout gadget, XCO full-suspension to XCC hardtail conversion, short-track race-ready](https://bikerumor.com/wp-content/uploads/2023/05/Cervelo-ZFS-5-LinkLock-prototype-lockout-gadget_XCO-full-suspension-to-XCC-hardtail-conversion_short-track-race-ready-800x533.jpg)
The Cervélo ZFS LinkLock is a relatively simple piece of CNC-machined 7000-series aluminum, engineered to accommodate the specific loads exerted on the frame while off-road racing with effectively no movement or loss of rider energy input.
![Cervelo ZFS-5 LinkLock prototype lockout gadget, XCO full-suspension to XCC hardtail conversion, with shock](https://bikerumor.com/wp-content/uploads/2023/05/Cervelo-ZFS-5-LinkLock-prototype-lockout-gadget_XCO-full-suspension-to-XCC-hardtail-conversion_regaulr-RockShox-SIDLuxe-shock-and-linkage-800x444.jpg)
Just bolt it into the same mounts as the shock & short link. It’s meant to be stiff and unmoving, leaving any flex or bump absorption to the carbon frame.
![Cervelo ZFS-5 LinkLock prototype lockout gadget, XCO full-suspension to XCC hardtail conversion, without shock, with geometry flip-chip](https://bikerumor.com/wp-content/uploads/2023/05/Cervelo-ZFS-5-LinkLock-prototype-lockout-gadget_XCO-full-suspension-to-XCC-hardtail-conversion_alloy-link-with-flip-chip-800x533.jpg)
Interestingly, this one functional alloy prototype was made with what amounts to a flip-chip insert at its attachment point to the end of the seatstays. This allowed the team to experiment a bit with the geometry of the ‘locked-out’ full-suspension hardtail. Did they want to replicate the position of the fully-extended unloaded shock.
![Cervelo ZFS-5 LinkLock prototype lockout gadget, XCO full-suspension to XCC hardtail conversion, short-track tuning](https://bikerumor.com/wp-content/uploads/2023/05/Cervelo-ZFS-5-LinkLock-prototype-lockout-gadget_XCO-full-suspension-to-XCC-hardtail-conversion_short-track-tuning-800x533.jpg)
Instead, Milan Vader raced the Nové Město na Moravě World Cup XCC short-track race in the forward flip-chip position that more accurately preserves the geometry of the bike as it would be at proper suspension sag.
What’s Next?
![Cervelo ZFS-5 LinkLock prototype lockout gadget, XCO full-suspension to XCC hardtail conversion, Milan Vader Jumbo-Visma](https://bikerumor.com/wp-content/uploads/2023/05/Cervelo-ZFS-5-LinkLock-prototype-lockout-gadget_XCO-full-suspension-to-XCC-hardtail-conversion_Milan-Vader-800x533.jpg)
Neither Jumbo-Visma nor Cervélo see the LinkLock as a realistic consumer product, but that doesn’t mean they’ll stop development work on it. I spoke with both Cervélo’s XC product manager and Milan himself today, and both seem passionate & willing to try out new ideas on the path to innovating cross-country race bikes.
![Cervelo ZFS-5 LinkLock prototype lockout gadget, XCO full-suspension to XCC hardtail conversion, bikes](https://bikerumor.com/wp-content/uploads/2023/05/Cervelo-ZFS-5-LinkLock-prototype-lockout-gadget_XCO-full-suspension-to-XCC-hardtail-conversion_complete-race-bikes-800x480.jpg)
And there will be another generation of the LinkLock. Next up will probably be a 3D-printed version, topology-optimized to shave weight off this aluminum version. The team will likely keep playing with the idea as long as World Cup courses necessitate a full-suspension XC bike for the longer XCO racing while a theoretical hardtail could be a better fit for the XCO short track.