Cervelo P2C

Chrissie Wellington wins 2007 Ironman World Championships on her P2C

Creating the new aero standard, the original Cervélo P2 (1996-1999)

Constant width cutout offers massively larger coverage surface than any other frame in its class

“The P2C packs a better punch than many bikes at twice the price”
- Triathlete magazine

“No upgrades are required. Slap on a set of race wheels and you’re ready to win Kona”
- Dan Empfield, founder QR and editor Slowtwitch.com

We again have to agree with Dan, in fact, somebody DID win Kona on a P2C. Early in 2007, Cervélo-supported teamTBB gave Chrissie Wellington the chance to focus full-time on triathlon. In October 2007, she stunned the triathlon world when she rode her P2C to victory at the Hawaii Ironman World Championships. Where did it all get started for the P2C?

In 1996, Cervélo pioneered what has become the defacto standard in aero frame design, the P2. Its aero downtube and seattube with rearwheel cutout was heralded as a significant leap forward in frame design. It is a testament to the effectiveness of this design that even today an original P2 would rank among the most aerodynamic bikes in the pro field at any triathlon or time trial.

As good as the P2 was, as always we found ways to improve it with the next incarnation – the P2K and subsequently the P2 SL. The aerodynamic performance of the P2 was improved upon while at the same time the weight was dropped. We also made it more user-friendly with Cervélo innovations such as our rear dropout adjustment screws, the ICS internal cable system and the seamlessly integrated aero seatpost instead of the cumbersome and unnecessary one-piece seattube mast.

Since we introduced the P2 series there have been many imitators and knock-offs, many of them in carbon fiber. Yet, none of them have utilized the carbon component to any great advantage. It was clear that we had to do it ourselves.

That’s why Cervélo developed the P2C. With the same front triangle as the Tour-de-France speed record breaking Cervélo P3C and a rear triangle that improves upon the original P2 by exploiting the shaping possibilities of carbon fiber, the P2 carbon is clearly ahead of other dual aero carbon pro frames. And all of this performance will be available to the regular consumer at a price far removed from usual pro-level bikes.

This is what we did:

1. A new rearwheel cutout shape, the first cutout of this type to take advantage of the opportunities of carbon fiber. Our biggest gripe with all the P2 carbon copies has been that the cutouts are made as if they are still made out of Aluminum. They taper at the top and bottom simply because that is what an airfoil shape does when you cut it further rearwards in a constant cross section.

   In Aluminum this is unavoidable, but in carbon fiber there is no reason to keep the seattube cross section constant. Its shape can be changed continuously to optimize the rearwheel cutout from top to bottom. We manipulate the cross sections of the seattube in such a way that at the point where it hits the cutout, its width is constant regardless of where in the cutout you measure. This width closely matches the width of the rear tire, thereby ensuring a smooth airflow transition from seattube to rear wheel. The combination of a constant width with a greater height of the cutout means that roughly 50% more of the rear tire is covered than any other P2 style frame available. Of course the P3C is another step beyond when it comes to covered area, as we pulled the cutout further around the rear wheel with that design.

2. The front triangle from the P3C was incorporated into the P2C. Of course, we could have made it less aerodynamic just because this frame would sell for less (sadly bike design often follows this bad version of “you get what you pay for”). But frankly, it would have cost us the same to make it that way as it does to do it right and we don’t feel we should punish people for no other reason than that they wish to purchase a less expensive frame.

3. The seatpost and seatpost clamp from the P3 Carbon was also retained. While it is a costly feature, the benefits are significant. It is simply the best way to combine the aerodynamic advantages of an integrated seatmast with the convenience of having a separate seatpost (no travel hassles).
4. Cable routing through ICS Internal CableStops and horizontal dropouts for a tight rearwheel cutout are obvious “must-haves” for the P2C.

So how good is the P2C? Consider that it has quickly become the frame of choice for professional riders who want to ride a Cervélo but whose teams won't allow them to ride something as obvious as a P3C. And although nobody would have noticed because it was not labeled a Cervélo, it was even used in the 2006 Tour de France, barely three months after its introduction.

Constant width seattube cutout – The cutout has a constant width, closely covering the rearwheel tire. Most cutouts (with the exception of the P3) have a cutout width that varies as you move up and down the cutout, thereby hampering the proper airflow from the seattube to the rearwheel.

Aero headtube - no bulky nose cone, but an extremely thin, aerodynamically optimized shape

New Cervélo aero carbon IAA seatpost - With its Integrated Accessory Attachment, this new seatpost can secure behind-the-seat components such as water bottle holders much more securely. Expect new products for the IAA system soon.

Integrated Seattube collar - By integrating the seattube collar completely into the toptube, we are able to smoothen the aerodynamic profile even further. The airflow doesn't even see the collar, yet the seatpost can be removed with ease. By integrating the seatpost into the frame aerodynamically but not structurally, you can fit the P2C into any bike case and travel without a problem, something that is very difficult to do with other integrated seatpost solutions that have the seatpost molded into the frame in one piece and that do not allow for the seatpost to be removed.

And we certainly have first-hand experience with this, as the original Cervélo P2 was the first bike to sport an integrated seatpost that was permanently attached to the frame. While it was the best solution we could come up with back in 1996, the new system with the removable seatpost is superior not only for traveling but also aerodynamically, as it allows us to use a much narrower seatpost than if it was a structural part of the frame.

ICS Internal Cable Stops - The best internal cable stop system available. Easy to install, easy to service, easy to keep clean and improved aerodynamics.

UCI legal - As with all our frames, the P2C is UCI legal

Frameset - The P2C is also available as a frameset

More aerodynamic frame – By exploiting the opportunities of carbon fibre, the headtube, downtube and rearwheel cutout are further improved. The seattube collar is also fully aerodynamically integrated.

When Cervélo first started using tube profiles as designed by the National Advisory Committee on Aeronautics (NACA), it caused quite a stir in the bike industry. These tubeshapes are the result of years and years of research and do a very good job of reducing the aerodynamic drag created by the tubes. We manufactured extrusion dies specifically for these NACA profiles, as it was the only way to get the tube shapes accurate.

But while NACA profiles are good, they are not ideal for bicycles. NACA profiles are generally designed for higher speeds, even those designed for "low-speeds" were made with speeds in mind that go beyond most cyclists' abilities. Therefore we have turned our attention to designing our own airfoils at Cervélo in the past few years, improving wherever possible on the foundation laid by NACA. The result is the latest family of airfoils, from the shapes used on the Soloist, Dual and P series TT/Tri bikes to the Wolf shapes optimized for frame and fork shapes adjacent to spinning wheels.

The tube shapes and aspect ratios on the P2C and P3 Carbon are a little different than on the Aluminum frames, which together with the other aerodynamic improvements (cutout, headtube, etc) accounts for the improved aerodynamic performance.

77-78 degree seattube angles have become more and more common for time trial and triathlon bikes in the past few years. Whereas in the past time trialers often rode at more shallow angles in the 74-75 degree range, the situation is no longer as lopsided. Riders like Zabriskie, Voigt, Julich and many of their Team CSC colleagues now ride at 77-78 degrees, and if it weren’t for the restrictive UCI rules on saddle position, some might even ride steeper. Other teams are starting to catch on to this trend as well, and no wonder if you look at the results Team CSC garners in time trials.

But even if you aren’t a professional cyclist, there are compelling reasons to ride steep on a time trial bike:

1. With lower back flexibility often a limiting factor, a steep seattube angle allows you to attain a flatter back without having to change your body’s “internal” angles (hip angle, knee angle, etc). Basically, a steeper seattube angle rotates the rider forward around the bottom bracket, thereby leaving the internal angles intact while positioning the back more horizontal.
2. A steeper seattube angle can allow you to even open up your hip angle, thereby reducing the strain on your lower back as well as making the pedal motion less restrictive.
3. For triathletes, several studies have shown that running times after riding a bike decrease if the bike was ridden with a steep seattube angle.

That said, a steep seattube angle is not for everybody and it remains a personal preference, so we offer our TT/tri bikes with adjustable geometry, allowing for an effective seattube angle anywhere in the 74-79 degree range.

As you move through the range of effective seattube angles, the effective toptube length also changes.

Note that we say effective seattube angle, as the standard seattube angle is really a very inadequate dimension. It does not describe very well the position of the point that actually matters for fitting, the saddle. A 75 degree seattube angle with a large setback seatpost and the saddle pushed backwards is a lot less steep than the same seattube angle with a zero-offset post and the saddle forward. The variation between these two situations can be as much as 3 degrees, yet both are called 75 degree seattube angles. So to really be able to intelligently compare positions, it is better to use effective seattube angles, which is normalized for a standard seatpost setback and a saddle position in the middle of the range. In the example above, we would call the first situation an effective seattube angle of 74 degrees, and the second situation an effective seattube angle of 77 degrees. In other words, you can achieve the same position for the saddle (and therefore the rider) with different seattube angles, as long as the seatpost and saddle position are adjusted to create the same effective seattube angle.

In the geometry tables below we list the dimensions for 75 and 78 degree effective seattube angles, roughly corresponding to the two positions of the adjustable seatposts if the saddle is clamped in the center of the rails.

During the development of the P2 and P3 models, Cervélo has ensured that these models comply with the new UCI regulations that came into effect on January 1, 2000. The main points of the new rules are:

1. Frames have to be of a double diamond lay-out
2. Both wheels have to be the same size
3. All tubes have to fit within a 80mm wide template, except near the joints where more room is allowed
4. A credit card has to fit between the seattube and the tire. Don't jam it through, as the official may not try that either. Just play it safe, and if there is any trouble sliding the credit card through, move the wheel a millimeter further back. A 3mm gap will enable a credit card to slip through without a problem (2.1mm should do it theoretically). The horizontal drop-outs of our TT bikes enable the rider to achieve the appropriate gap irrespective of the size of tire used.

Several national federations are working on a grace period so that people with old bikes can still compete in events. But this grace period will likely only apply to bikes purchased before January 1, 2000, so if you are looking to buy a new bike, please ensure that your bike is approved by the UCI. And for more information on a grace period, contact your own national federation.

The link below will show you the UCI approval of our models. To make sure things go smoothly at the pre-race technical inspection, you can print this out and present it to the commissaires. Be sure to print it in grayscale and high quality for proper reproduction of the drawings. Click here to view the UCI approval