The P4 is the eagerly anticipated successor to the current time trial standard, the Cervelo P3. As the P3 is still the fastest bike available three years after its introduction, it is clear that creating its successor was no easy task. After millions in research & development and over two months of intensive testing at the San Diego Low Speed Wind Tunnel, the P4 is the fastest bike ever in the wind tunnel, including both UCI-legal and illegal bikes.
“The P4 is the biggest leap we have ever made in aero bike technology,” said Phil White, co-founder of Cervelo. “The P series has evolved significantly over the last decade, making it a real challenge to keep finding improvements. With the P4, the mandate was to make it significantly faster than the P3 while achieving equivalent or better performance relative to stiffness, power transmission, low weight and comfort. I’m pleased to report that we have met those goals.”
The strengths of the P4 are found in its many fine details, some of which are quite visible but others are difficult to detect at first glance. The key to the performance of the P4 lies in the frameset’s integrated design.
The custom fork, developed by vroomen.white.design, is integrated seamlessly into the head tube and downtube. This feature was first conceived by Cervélo in 1995 and comes to fruition now on the P4. Cervélo also invested significantly to optimize the spacing between the tires and wheels, the frame and the fork. This is a very complex area aerodynamically and our engineers tested over seventy-five different designs during the development process. The result is a significant reduction in drag values generated in this section of the bike.
Optimized Aero Tube Shapes
The aero profiles of the P4’s tubes are completely new, improving airflow attachment and reducing turbulence relative to other designs. In addition, the new asymmetric aero chain stays generate very low drag values, particularly in cross-wind environments, compared with chain stay designs from earlier P-series and competitor models. Finally, the seat stays are pitched forward to reduce frontal surface area and their joints with the seat tube are optimized for maximum aerodynamic efficiency.
Front wheel cutouts
We invented the front wheel cutout back in 1995, but in subsequent testing we have found it not to be the fastest design. So despite current trends the P4 does not have a front wheel cutout, as we have never seen one that works. While front wheel cutouts can show good drag values in the tunnel, this is only the case because there, the front wheel is perfectly in line with the downtube. In reality, the rider constantly makes small steering adjustments, which stalls the airflow onto the downtube and increases the drag.
The P4’s custom rear brake is fully designed and developed by vroomen·white·design. It is positioned behind, rather than underneath the bottom bracket as is commonly done (and which significantly increases the frontal area and thereby the drag). Thanks to the structural carbon brake booster, the brake has the same power and modulation as a Dura Ace brake while being 30% lighter. The brake booster is easy to remove for full brake service and allows access to the brake mechanism for quick adjustments on the road.
Traditional bottle shapes corrupt the efficiencies of proper airfoil tubes. The 570 ml water bottle on the P4 is designed so it does not disrupt the airflow, and it contains more fluid than a standard water bottle so it is more practical. Its shape and position also make it easy to grab and drink from according to our test riders.
The bottle is refillable on the fly, important for longer races. For those using two types of fluids in races, we recommend a set-up including this P4 bottle plus a standard bottle cage attached to the aerobars. Having a standard bottle in-between the arms on the aerobars makes it easy to hydrate, and there is no aerodynamic penalty. It also reduces the need to refill the P4 bottle, as you can opt to have a high-density energy drink in the P4 bottle and water in the aerobar-mounted bottle (which you renew as you race along). Additional P4 bottles are also available, so you can have a ready-to-use fresh dose of energy drink in your special needs bag at Ironman events.