Cervelo P5 - the full details for the time trial bike

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This article first appeared on Bikeradar.

Cervélo have officially unveiled their new P5 time trial/triathlon bike at their 2012 BikeBrain event on the Spanish island of Fuertaventura.

With competition in the time trial and triathlon sector more ferocious than ever, there has been much speculation as to whether the Canadian company would follow the Specialized Shiv’s lead and make separate triathlon and UCI-legal frames.

In fact, Cervélo have chosen to put all of their research and development into producing a single frame that’s their most aerodynamic ever as a UCI legal machine, and which can be further advanced with triathlon add-ons.

The UCI-legal version – the P5 – comes with a narrow fork much like the P4, while the P5 TRI will ship with all the extras including a wider fork that works in combination with a nose cone brake cover and ‘beard’ – a section that links the top of the brake cover with the stem. The P5 TRI also gets Magura’s incredible new RT8TT hydraulic brakes and the new Cervélo-3T co-developed aerobar setup.

Cervélo’s buzzwords with the P5 are ‘Simply Faster'. “Everything has both a simplicity aspect to it and a speed aspect to it,” says Phil White, founder of Cervélo. “If you look at what’s happened in the bike industry over the last few years, everything has got more complex. Nothing works together with an industry standard, which means in a lot of cases they’re made from far-worse-than-industry-standard parts.

“Here we sat down and said, ‘this is the wrong direction; it has to get simpler'. We have to stick with the industry standard interfaces but we have to make it faster as well. It’s faster and simpler in everything we do.” This ethos is found throughout the bike’s four key areas: frame, aerobar, brakes and storage solutions.

The most obvious change with the bike compared to its predecessor, the P4, is a much more aggressively styled frame. These striking new tube profiles were developed using Computational Flow Design (CFD), where bike frame iterations were modelled against a virtual wind tunnel by a 16-core computer. From here, the tests were validated in real wind tunnels, saving Cervélo time and money as well as allowing more creative frame design.

This process has led to frame profiles that go to the limit of UCI regulations, beefing up tube junction points to boost stiffness and aerodynamics in one swoop. The seat tube/top tube junction, or chord, is almost twice as long as the P4’s. Cervélo say this gets around the UCI’s 3:1 restriction on tubes with the specific shapes and trailing edge helping to create a smaller zone of negative pressure, which keeps the flow attached to the frame after it comes off the rider.

Behind this, the TrueAero cutout for the rear wheel allows wheels from 17 to 28mm and tyres up to 25mm to maintain the 2-6mm gap between frame and tyre that Cervélo have found to be a sweet-spot for aerodynamics in wind tunnel tests. So although the bike was designed with Zipp 808s, the frame’s aerodynamics remain uncompromised by other wheel choices.

The bottom bracket height is lower than on the P4 to reduce drag and improve handling. It also integrates the asymmetric BBright system, the first to incorporate both an oversized 30mm axle and oversized frame tubes. While the BBright system doesn’t make any gains or losses aerodynamically, it’s designed to improve responsiveness and acceleration. By almost doubling the size of the chainstay on the non-drive side, and the seat tube and down tube also getting larger as they flare into it, Cervélo say there’s a significant stiffness improvement compared to a traditional bottom bracket.

At the front of the bike, Cervélo’s TrueAero head tube provides a near perfect profile across fork, frame and brakes thanks to the matching of the fork profile with the nose cone brake cover (also improving fork stiffness), the down tube and the beard. This adds up to their most aerodynamic head tube shape ever.

Cervélo have also improved their cable routing, with the frame being engineered to minimise bends, meaning cables and brake lines taking as smooth and friction-free a route as possible through the frame, which Cervélo also say maximises shifting performance and increases cable maintenance intervals.

The frame itself has been produced using tools and techniques from Cervélo’s Project California. This Comfort Ply layup technology utilises different carbon materials and layups to tune frame properties in different directions in order to make a light, stiff, and comfortable bike. This is good news for comfort over long time trials and keeping legs fresh for the run in triathlon. Although Cervélo always prioritise aerodynamics over weight savings, thanks to these technologies, they say the P5 frame weighs in lighter than the P4, although there are no confirmed frame weights yet.

Co-produced by Cervélo and 3T, the new aerobar on the P5 is claimed by Cervélo to be the world’s fastest. It’s a simple system compatible with any standard 28.6mm steerer, keeping additional hardware to a minimum, and features completely hidden cables, reducing drag by up to 40g. Featuring industry-standard fittings, this ‘Aduro’ bar, which is only available in a 38cm width, will reach the market through 3T soon.

There’s plenty of adjustability in the aerobar too, through either a 105mm tall High-V option designed to raise the bars into a more upright triathlon position, or a lower profile bar that the extensions can either be set on top of at 60mm or underneath at 40mm. All of these options simply bolt onto the base bar.

There’s also additional adjustability available thanks to 5mm and 10mm spacers that slot between the beard and stem to increase the armpad stack height while maintaining the aerodynamic shapes of the headtube. None of this impedes the cable routing either, which, like the frame, is designed to be as twist and kink free as possible.

All this means that the all-important armpad stack height has more adjustability than on the P4 despite simplification of the whole bar system. This fulfils the wishlist of Garmin Barracuda who wanted to get even lower than the P4 allowed. The bars also only have a handful of parts, making it much easier to strip them off for packing in a bike case – a key consideration for triathletes.

There’s also plenty of travel in the armpads to allow setting up of riders’ correct aero positions without having to produce multiple stems. The nominal stem length is 90mm with a 50mm fore-aft adjustment possible through a series of bolt holes on the armpad cradle. Any standard extension bars are also compatible (though the P5 will ship with S-bends) and can telescope in and out of the aerobar base.

Regular water bottles are back

One of the other main features of the aerobar is its hydration integration, which is one of the storage solutions Cervélo have implemented. Rather than an internal bladder as seen on the Shiv, Cervélo have opted for a simple bracket for a regular bottle cage. Cervélo say the fastest position for a water bottle is between the arms.

This feature, which saves four watts by filling the gap between the forearms, allows riders to quickly and easily access their drink and swap bottles in a triathlon with none of the faff associated with getting the liquid into aftermarket aero bottles that hang between the extensions. It should be noted however, that this aerodynamic benefit is lost in the very lowest 40mm bar position.

Cervélo’s previous attempt at integrated hydration – the P4’s triangular drink bottle that sits just above the bottom bracket – has evolved into an optional storage box that will be available from third party suppliers. This change was simply down to feedback about how the space was more frequently used for storage than drinks by P4 riders.

Two more third party storage add-ons will also be available. The first is a silicone topped, aerodynamic Bento Box that can be bolted to the top tube, extending the back of the stem into a sweeping aerodynamic section. The second is a bottle holder that integrates with the back of the aero seatpost to allow a greater number of bottles on-board without disturbing airflow.

Finally, there's also Cervélo’s Hidden Pocket, which is a battery compartment for Shimano’s Di2 electronic shifting system located on the inside of the seat tube and accessible with the removal of a single Phillips screw. Hiding away the battery pack has a claimed aero benefit of 10-20g of drag. If riders choose not to use Di2, the Hidden Pocket can be used for carrying spares or small tools.

Improved braking with Magura's RT8TT hydraulic system

Perhaps the change for the P5 that will be met with the warmest reception from both TT riders and triathletes is the complete overhaul of the braking system. Riders have often lamented the P4’s somewhat archaic rocker-actuated cantilever setup, but this has now been superseded in every way by the new, custom designed RT8TT hydraulic brakeset from German company Magura.

The hydraulic system works with two pistons, one at the lever and one at the brake, which lifts a wedge to pull the arms of the brake together. Unlike a cable system, the hydraulic line is unaffected by twists and turns, meaning there’s no lag in braking, making them very responsive and very powerful. In addition, the levers are much more sensitive to pressure, helping to reduce fatigue in hands and forearms when under hard braking. They use a standard single-bolt mounting, are said to be unaffected by heat and fit any standard brake shoes.

The RT8TTs have a built-in quick release system that's accessed by flicking a small switch on the inside of the brake lever. This relieves tension in the line and allows quick wheel changes. Once the new wheel is in place, there’s no need to set up the brakes differently either, as the travel on the RT8TTs is so long that they'll work comfortably on all standard thickness wheels from 17-28mm without shims.

In line with Cervélo’s desire for simplicity, the brakes use a self-lubricating hydraulic system with mineral oil, meaning there’s no need for regular line changes. In fact, Magura say the brake’s properties should be maintained forever. If the brakes do need servicing for whatever reason, a combination of two easily accessed bleed ports and existing Magura tools make it simple for Magura dealers to work on the system.

The brakes have also been designed with aerodynamics in mind. Though the back brake is hidden under a bolt-on casing on both the P5 and P5 TRI, it's only the latter that benefits from the aero nose cone to increase aerodynamics at the front of the bike. Despite this, thanks to the minimalist design, there's a significant improvement in aerodynamics – creating only 1,872g aerodynamic drag, compared to a standard side-pull (1,886g) or cantilever brake (1,881g). Including the nose cover, the aerodynamics are improved further still to 1,865g.

All of this comes as a package that's the lightest on the market, with the whole brakeset (front and rear including lines, mineral oil and levers) weighing in at an astonishing 495g, significantly less than other offerings. Though Cervélo have exclusivity on the brakes for a year, Magura have set the price for front and rear RT8TTs including levers at €599.
Pricing

Cervélo have also confirmed the prices of the P5, which will begin shipping next month. The regular P5 will be $4,500 for frame, fork and seatpost, or $6,000 built up with mechanical Dura-Ace. The P5 TRI, which includes frame, aero fork, seatpost, full aerobar set p, nose cone brake cover, beard and the Magura brakes will retail at $6,500, while a P5 TRI built up with Shimano Di2 will cost $10,000.

The P5 certainly seems to answer the challenge levelled by Specialized’s Shiv of producing a single frame that can be set up distinctly differently for the time-trialling and triathlon crowds. It offers virtually unlimited options, but thanks to Cervélo putting emphasis on simplicity, these can all be achieved using standard, off-the-rack kit. Meanwhile, the bike’s new faster, lighter frame, slick aerobar, storage options and unmatched brakes make it hard to imagine Cervélo’s dominant position at the Kona Bike count coming to an end any time soon.