Cervélo came into existence pushing the envelope. The P5X goes back to their roots with a radical triathlon bike not constrained by the UCI or accepted wisdom. It’s not just the lack of a seat tube, or the disc brakes, or the modular handlebar design, or the storage systems. It’s everything.
Cervélo realized that as smart as they were, they needed some outside help. Hed, long an aero pioneer, is also great with carbon fabrication, and Cervélo outsourced frame production to Hed’s facilities in Minnesota. ENVE has a proven track record with aerobar systems, and Cervélo asked them to help design the cockpit.
The design mandate was to build a bike that was faster than the P5 in Ironman conditions. They started by analyzing the position and gear placement of thousands of triathletes. No matter how fast a frame is in the wind tunnel, how a rider sits on the bike and where her nutrition and tools sit is arguably more important. So they needed to figure out how to integrate these features into whatever they built. For example, they realized that they needed to build the bike on the assumption that the riders employed round bottles, as those are far more common than aero bottles.
When they tested out the bike in the wind tunnel, it was both fully loaded for an Ironman against other bikes fully loaded for an Ironman. As they’re proud of their P5 for being one of the fastest bikes around, they needed to beat the P5. Which they did. The P5X, geared up for an Ironman has 31g less drag than the P5. And it’s faster than the P5 at virtually all yaw angles. The P5X is also stiffer at the head tube and equally stiff at the bottom bracket. Yes, there is a weight penalty, 13% over the P5 when both are fully loaded, but at Ironman distances, the aero gain far exceeds the minor weight penalty.
Fast is important. But it also needs to fit. Here, too, they wanted to exceed the P5 in terms of flexibility. Even though there are only four sizes available, thanks to smart thinking, it fits a wider range of bodies. You should check out their fit calculator. It’s not just that the top tube dips in the middle, offering less stack than other frames of its size, or that the seat post has a huge range of vertical and horizontal adjustability (the sliding rail allows for the seatpost to move from a virtual 74-degrees to a virtual 81 degrees). It’s that the front end is more adjustable than just about any setup you can cobble together on your own.
The base bar flips, to be either 40mm below the clamp or 40mm above. The extensions have a stack adjustment range of 0-112mm, with a built in wedge on the front of the bayonet holding it securely. The pad width adjusts from 166-220mm center-to-center. The pads have a fore-aft adjustment range of 91mm, and the bars, which can be adjusted or cut or changed-they have the industry-standard 22.2mm width-and the tilt can be adjusted from zero to twelve degrees.
The bars not only have a wide range of adjustment, but easily break down for travel. The extensions can be lifted off in a single piece while the base bar breaks in two. In fact, easy break-down for travel was one of the design requirements. Cervélo even worked with Biknd on a custom version of their Helium travel bag, including protective sleeves that hold the base bars in place and pad them on the outside of the fork. The bag also allows for two sets of wheels as well as helmet, shoes, and other bike gear.
We’ve mentioned nutrition and gear storage. As noted, where and how you place bottles, bags, pumps, kits, etc, can have a profound effect on aerodynamic drag. Cervélo decided to build it in, as a way to ensure that the aerodynamic gains created in the lab were replicated on the road. A behind the stem bento box can hide bars, gels, capsules, as well as your phone, a Di2 junction box or SRAM Blip Box. There is also a removable downtube storage box. When it’s on the bike, a bottle cage goes on top and a door flips open, revealing a space large enough for more nutrition or tools or both. When it’s off the bike, there are still downtube bottle mounts. There’s a Stealth box between the crank and the front wheel. The cover always stays on, but the interior box can be installed or removed, depending on your needs. There’s room for a tubular or two, as well as tubes, tire levers, multi-tool, and inflators. A space made under the seat clamp has room for a post that is strong enough to support one or two bottles. And there is room for a between the arms bottle by the extensions as well.
As this is a bike for the future, Cervélo built this with 12mm thru-axles and disc brakes. The bike aerodynamics were designed with these brakes in mind. While it is new tech to learn, the bakes are easier to work on than many integrated brake systems.
Finally, the P5X embraces all of Cervélo’s modern standards. 25mm tires fit easily. The bike has the BBright bottom bracket shell. It has future-proof cable management. Yes, electronic is easier, but if you prefer cable-actuated shifting, you can do it as well. The flat-mount caliper mounting standard works best with 160mm rotors, which is why they come with the bike.
The Cervélo P5X is a uniquely fast bike designed for the real world position and nutrition needs of the triathlete.