Design Engineering

In the Pursuit of Victory

Lindsay Luminoso   

bike Cervelo

Toronto-based Cervélo invests three years designing the ultimate triathlon bike

Cervelo p5xFor the past two decades, Cervélo engineers have been designing the world’s fastest bikes. It’s no surprise then that the sport’s top athletes consistently choose the Toronto-based company’s high-end endurance, track and time trial equipment. At the Beijing Olympics, for example, more than 40 riders opted for Cervélo bikes, 10 of whom won Olympic medals.

In triathlete circles, the company’s triathlon/time-trial P-Series has become the standard. According to Lava Magazine, an online publication dedicated to elite triathletes, 577 of the sport’s top competitors rode Cervélo’s P-Series at the 2016 Ironman World Championship in Kona, Hawaii last year, more than twice as many as the second most common bike brand. In fact, the Canadian bike maker has topped the magazine’s prestigious Kona Bike Count for the past 12 years running.

Yet, despite its clear dominance in the field, Cervélo’s design team decided in 2013 that they needed to kick it up a notch. They wanted to move beyond the traditional engineering options and design the ultimate bike for triathletes. This is where the idea for the P5X bike was born.

“We don’t design a bike to look nice necessarily; we design them to be the best technically that they can,” explains David Killing, senior designer at Cervélo. “We are definitely engineering design focused, trying to make the bikes perform the best in whatever sense they need to perform, whether that is aerodynamics, stiffness, weight or even human interface. That really drives our design quite a bit.”


With an engineering department of 12 people, the team decided that they needed to throw out the rules they had applied to previous bike designs.

The P5X project began with an extensive research phase so the designers could better understand the unique challenges triathletes encounter. They traveled around the world to various triathlon events, took thousands of photos of riders and interviewed countless pro-triathletes, bike fitters and coaches. This field research helped provide an understanding of how the bikes were being used, what people were carrying on their bikes and what positions were ideal for riders.

“Whenever an issue came up through the development of the project, we had this really strong base of knowledge to go back to and understand how the bikes were really being used and not have to speculate,” says Killing. This research stage of the project gave the team a set of priorities and goals to design towards.

One thing the team discovered early on is the stress associated with participating in a triathlon. For example, athletes have to disassemble their high-end bikes for shipping to the event and then reassemble and fine-tune them before the race. And when they’re riding 180 kilometers on a bike, considerations like where food and water will be stored become an issue.

“That was something we learned from the research we did,” explains Richard Matthews, senior composites engineer at Cervélo. “We could see from all the pictures that people were buying high-end triathlon bikes, worth tens of thousands of dollars, but sticking gels and water bottles and spare tires all over the bike with duct tape and electrical tape and the like. The research showed us that this was a requirement – riders need to carry their stuff – so we designed it into the bike.”

In P5X’s design, Cervélo’s designers realized they needed to solve these challenges by making the bike pack down as small as possible and therefore extremely easy to travel with. They also needed to allow riders the ability to fine-tune the bike’s configuration after initial setup. Most importantly, the design needed to include storage solutions for the various fuel, hydration and tools needed, without changing the aerodynamics and functionality of the bike.

“We wanted everything integrated and included in the bike solution,” says Killing.

In the initial design phase, Cervélo’s engineers looked closely at the shape of the bike. Killing explains that one of the main challenges they faced had to do with the placement of a water bottle on the frame. Early on, the design team decided they wanted to work with standard round water bottles, to make it easier for riders to refill or grab new ones during the race.

“One of the big questions for the team was: Where do we put this round bottle on the frame so it doesn’t interfere with the rider’s legs, is easy to access and aerodynamic?” Killing says. “A big part of the shape of the frame was based on where to put the bottles and storage. Without the seat tube, we can fit the bottle in there and have the storage box. You can see that in the shape we have.”

Cervelo P5X sketchThe layout of the frame was a challenge the engineers faced throughout the design process. Not only did the team want to incorporate large openings in the frame to increase aerodynamics and storage space but they also wanted it to be manufactured as a monocoque. The reason for this was two-fold: It would cut down significantly the cost of the tooling and would also make the frame much stiffer.

The P5X is made from carbon fibre but designing the layout of the carbon fibre of a monocoque frame presented its own unique challenges.

“We have rules we use for our regular bikes and a lot of those rules didn’t really transfer over to this bike,” explains Matthews. “Because the design was so different, we had to start over from scratch to determine how we would lay out the carbon fibre on the frame to make it work effectively. It took us longer than we had hoped to do that. In the end, it worked out well, and we learned a lot from those challenges.”

Another unique feature they decided to include was disc brake. Matthews explains that this was one of the first bikes designed solely for triathlons to include this type of brake. Primarily triathlon bikes used rim brakes. However, the team opted for disc brakes because they increase the quality of braking in different weather conditions and provide nicer modulation and finer control. The removal of the rim brakes also opened up some design freedom for the team as they were able to adjust the placement of the disc brakes to suit specific design functions.

“When you move from a rim brake to a disc brake, the area where the rim brake used to be – on the top of the fork at the front of the bike – is now much more unconstrained and we could design that to be more structurally and aerodynamically influenced,” explains Killing.

Disc brakes also provide an advantage when it comes to tire size. There is a push in the industry to use larger tires, as they tend to offer more comfort for the rider. However, rim brakes limit tire size; tires  too wide can create braking interference. In addition, using disc brakes enabled designers to reconfigure the frame to make it more aerodynamic while also meeting riders’ accessory needs.

Another big design win for the team, Matthews explains, was the high level of adjustability they achieved. The P5X only comes in four different sizing options, while other bikes in the company’s P-Series have seven different sizes to fit a wide range of riders. However, this particular model is designed for micro and macro adjustability and therefore covers a wider range of sizing options with fewer models.

From start to launch, the P5X took approximately three and a half years to develop and manufacture and includes a wide range of features that culminate to what the company calls “the ultimate triathlon bike.” Cervélo also boasts that the P5X underwent more than 180 hours of wind-tunnel testing, along with extensive CFD analysis of 150-plus frame iterations. On average, the P5X is 30 grams faster than the P5 at +15 to -15 yaw angles in a full Ironman setup.

“We were able to provide all the features that we wanted to get to the user into a final product,” Killings says. “We didn’t have to resort to making it a concept bike. One of the features that really set it apart is the ability for the bike to pack down very easily. We’ve also included an intended bag that has everything thought out and can easily transport the bike. It takes all the stress out of the packing process.”

“We were also able to get in a wide range of adjustment into the front end of the bike and make adjustment available to the user to tweak and play with throughout the lifespan of the bike,” he adds. “And then having the different places to store fuel, hydration and tools on the bike so you can still set it up how you like was very important. Each feature is well thought out and solves a unique challenge. We really wanted something clean, elegant and aerodynamic.”


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