Trimes digs Damon Rinard, Senior Engineer at Cervélo, about the new P3

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Cervélo's Damon Rinard
Cervélo’s Damon Rinard

One would be inclined to believe that a niche company that experiences such great success would be shrouded in secrecy. In the reality, Cervélo are quite the opposite, are always willing to share data and to educate its target audience as to what is and what is not aerodynamic. Damon Rinard, Cervélo’s senior engineer, chatted with and shared generous, detailed information and forthright answers to our bike geek questions. Trimes digs Rinard about Cervélo’s new working man’s superbike: the P3.

Trimes: The P3 has been a revolutionizing product in the industry because it was pushing the edge of what could be achieved with carbon. Was keeping the P3 moniker a hot debate? Should it be kept as is? Should another iteration be baptized to denote a clear distinction?

Damon Rinard: You’re quite right. The P3 did push the envelope. It is still the world’s most decorated tri bike, and still succeeds in competition today. But – we’ve pushed the envelope further since then: for example, with the P5 and S5 models. We wanted to keep the same name because the new P3 follows the heritage of the classic P3: aero, performance, innovation. We did add a letter some years ago to make one distinction. When the P3 was first created it was aluminum, and then we introduced the P3C – the ‘C’ was to designate the carbon variant. A few years ago we dropped the ‘C’. And now since the new P3 takes the place of the classic P3, there was no name change. (This is similar to cars, where the new model keeps the same name.)

Trimes: With your naming system, with the retirement of S3 and P4 and the fact that we never got a S4, we have the feeling that some development bikes have been abandoned or may even still in the works? Any juicy details you can share with our readers?

DR: Yes, of course, in an innovation/engineering-focused company like Cervélo there are always bikes in development … and, sorry, we can’t tell you about them yet! The bikes you mention are major parts of the heritage of the newer models, so in that sense they aren’t retired. We always learn from what came before and we always incorporate this learning into new models.

Trimes: What was the design objective of the new P3? Who is the target customer?

DR: The target group can be defined as the dedicated age group triathlete, although some pros will also be riding the P3. The overall objectives can be summed up in the phrases “Simply Faster” and “Speed Within Reach”

Simply Faster” applies to all new P-series Cervélos (P5 and P3) and means we engineer the fastest bikes, without over-complicating the owner’s life.

Speed within Reach” applies to the new P3 and means we keep nearly all the P5’s speed, while bringing the performance, fit, simplicity and price within reach of more athletes.

These objectives are met with the P3’s new geometry (same as the P5); lots of aerodynamic elements from the P5; and while the P5 introduced the simply faster concept, the P3 continues it. The standard stem, brakes, and headset all make this bike simple to live with, plus you get the benefits of superbike DNA, our aerozone engineering analysis, dropped down tube, lots of storage and hydration options, and BBright. [Editor: more details about these technologies]

2013 Cervélo P3
2013 Cervélo P3

Trimes: Since the previous iteration of the P3 may be the most iconic and copied TT bike, I suspect that improving upon it was quite a challenge. The latest version shares design elements from the S5 and P5. Notably, the previous curved seat tube is replaced by a wheel cut-out seen on the latter. It looks like your are so comfortable about your latest design that there is almost no place to improve, no?

DR: You’re right, the classic P3’s general form (though not its performance) is frequently copied by many other brands and you’ve identified the most copied element, the curved seat tube. However, in the new P3, the seat tube leading edge is changed to be more like the S5 and P5 because we’ve learned a lot in developing those newer models, and wanted to include those advances in the new P3. Picture a family tree: the old P3, then its younger siblings: the S5 and P5. Technologically, the new P3 is a descendent of these newer 5-level bikes, but spiritually, it inherits the name of its “grandfather”, the classic P3.

2013 Cervélo P3 - Details of the rear wheel cut-out
2013 Cervélo P3 – Details of the rear wheel cut-out

Trimes: As a junior, I rode a 63 cm steel frame that would bend and buckle under any kind of sprint or hard effort. What is Cervélo’s approach to building frames that are adapted to sizes? Are layups, tube diameters and tube thickness the same throughout the range of sizes?

DR: Yes, you’re right: when the tube width decreases, the mechanical properties (strength and stiffness) decrease as well. That’s why so many carbon tri bikes have compromised performance. However, we began engineering carbon aero bikes long ago, so we’ve developed several smart engineering solutions to increase the mechanical performance of the frame while keeping the best aero shapes. One example, used in all Cervélo models, is SmartwallTM, which adds the most reinforcement at the least weight, while maintaining the good vertical compliance of the bike. In the new P3 (and P5), we’ve gone a step further, applying the engineering techniques we learned in our Project California engineering facility. Using our advanced composite engineering analysis software tools (unique in the bike industry), we engineered a carbon layup technique we call ComfortPlyTM technology. The results of the analysis not only tell us how to most effectively strengthen and reinforce the frame, but also what fibres are not needed for strength and stiffness. ComfortPly technology removes these unneeded fibres, which saves weight and adds comfort. This is important in a tri bike because it helps to have fresh legs when you start the run.

Cervélo layups are individually developed for each size. Every size keeps the optimal aerodynamics in the external form, but we vary the internal composite layup of each size including fiber types, amounts and orientation. (This size-specific variation in layup is one of the reasons it’s difficult to describe a Cervélo by simply naming the type of fiber it contains, which would be a misleading oversimplification). Especially important for out-of-the-saddle response is BB stiffness. In this case, every Cervélo frame size benefits from BBright: asymmetric, stiffer and lighter.

Trimes: How much has the carbon layout procedure evolved since the first P3. Is it uni-directional carbon? Any influence from Project California?

DR: I think we’ve touched on some of this in some of the earlier questions, such as the Project California technology. But yes, all Cervélos are made using mostly uni-directional fibres. Small pieces of woven cloth are placed strategically where they do the most good: for example, where there are complex shapes or multi-directional stresses.

Trimes: It is unavaoidable that bike geeks are going to compare the cost/benefits of buying a P3 versus buying a P5. Do you have any numbers outlining the difference? Is it possible that the P3 can be faster than the P5 in certain conditions, like a hilly course, for example?

DR: You’re right, it’s a natural comparison. I’ve included a slide that shows the difference between the P3 and other bikes in its category, as well as ‘superbikes’. You’ll see that we’re drawing that line at bikes less or more than $6,000, and consider ‘superbikes’ to be those with an integrated stem. You can see that on average there is a 68 gram [of aerodynamic drag] difference between the P3 and the P5-Six. This is equivalent to about 6.8 Watts at 40 km/h.

Average aerodynamic drag comparison of various Superbikes. Source: Cervélo
Average aerodynamic drag comparison of various Superbikes. Source: Cervélo

Trimes: As a project manager, your role is to ensure that the industrial designer is still the friend of the composite engineer. Can you tell us more about the process and the decisions you need to make?

Mike Trigonidis: When we start a project we bring the full team together (designers, engineers, managers, etc.) and we work as a team to define how we will accomplish our goals. We have a set process at VWD (Vroomen-White-Design) in terms of our projects where we follow set stages and gates so that we are sure we are always moving in the right direction.

In some cases we will reach a gate and decide that we need to go back and make changes before we can pass through. All of these stages and gates involve the full team’s involvement so that everyone is always aware of the decisions being made and understand how they can affect the outcome.

In the case of the P3 (as in all of our projects) the Industrial Designer is hands-on with the design from day one, including brainstorming ideas, sketching various options, and moving on to the CAD portion of the design. The Industrial Designer and Structural Engineer (and Aerodynamicist) are in constant communication to ensure the choices made in the design do not impact the bike in a negative way.

We must consider our functional goals first and foremost and only when we meet them can we look at the form. We as a team need to consider design for manufacture as well, since we cannot simply design random shapes if we cannot ultimately produce them. Carbon fibre allows us to do a lot of radical things in our designs, but there are some things which even carbon fibre cannot accommodate, so the Composites Engineer must be involved to ensure the Designer does not cross the line, so to speak. Ultimately, we strive to push the limits (and even go beyond them if the project calls for it) on every project we undertake, but by following a structured process we can do this in way where we understand the risks and understand how to deal with them.

Trimes: Some aspects of the new P3 don’t seem to be following industry trends. Cervélo does not seem inclined to integrate front brake behind the fork or the rear brake below the bottom braket. We don’t see an integrated stem or fork/steer tube assembly either. The above features all seem to offer an aerodynamic advantage but the reality may be different. What is the reasoning behind these design elements?

DR: Great question. As you can imagine, Cervélo has tested a lot of bikes in the wind tunnel. The features you mention exist on a few competing brands we’ve tested, and in addition to those, we have also tested prototype bikes with similar features in different forms. So we have the comparison data on most of these concepts. Since the goal at Cervélo is to help our athletes go faster, we always choose the fastest options. For example, the with the Magura brakes, our engineering analysis shows that the air flows over the brake, the fork, and the frame, smoothly such that hiding the brake offers no significant improvement. The brake, fork and frame are arranged one after the other in a stream-wise direction and their dimensions and shapes are engineered to work together: each following part drafts off the leading part. This is true in the front brake as described, and also the rear brake, which drafts off our shielding seat stays. Bottom line: hidden from the eye doesn’t mean hidden from the wind, and hidden from the wind doesn’t mean hidden from the eye. We do the research to choose the fastest design features for our clients.


Trimes: What’s the reasonning behind dropping the bottom bracket height on the new P3?

DR: The classic P3 was designed in an age when TT specialists rode longer cranks. Simple answer, but true.

Trimes: The BBstop system is new design element for the P3. I suspect mechanic’s are going to be pleased about this cable management solution! The P3 looks like an easier bike to wrench on.

DR: The BBstop is a novel solution to having one frame compatible with hydraulic, mechanical and electronic controls. BBstop simply reflects the shift in relative popularity of electronic shifting and mechanical shifting. The ICS3 guide tubes are optimum for mechanical and still work well with electronic. With BBstop, we simply chose to eliminate the guide tubes in the frame, so the housing now stops at the bottom bracket. BBstop is optimum for electronic and still works well with mechanical. Bottom line: every new P3 frame is ready for mechanical, electronic and hydraulic controls. [More information about BBStop]

Trimes: The Specialized Shiv has targetted the triathlon market quite directly with the internal bladder system. Has Cervélo considered implementing a similar feature?

DR: Yes. We prototyped internal drink bladders around 2007 or so, and found logistically it was very difficult to keep clean, install, refill, etc. And most importantly, the straw ruins the aerodynamics. Instead, we recommend options that actually make you faster, such as a standard bottle between the arms. Have a look at figure 3 in this article.

As well, the P3 includes lots of aftermarket storage and hydration options integrated into the design of the frame. Have a look at the diagram here. These storage and hydration features of the P3 fit perfectly with the P-series focus on “Simply Faster”: fast bikes that are also simple to use and work on.

Trimes: I was honestly surprised about cable exit of the rear hydraulic cable. Why does it exit now in the centre of the tube and not on the side? Do hydraulic cables needs to be run differently in the frame?

DR: Hydraulic hoses are highly tolerant of sharp bends, etc., so the brake cable routing was chosen primarily to reduce friction in mechanical cables (with smoother curves) and reduce interference with the leg. Here’s how: There are three choices: side, bottom or top. If the cable exits the side or bottom, it can rub the rider’s leg (we learned this with the P2 and P3). Also, exiting the side or bottom means the cable path goes down, then up and finally down again. These extra bends add friction. Therefore the best choice is to exit the top, as you’ve noticed. Exiting the top, the cable simply continues its natural upward path inside the top tube, followed by only a single smooth arc down to the brake. Friction is unimportant for hydraulic, but this path keeps the hose out of the way. This is another example of a small detail that we studied carefully to provide the best performance.

Trimes: What was the implication of Vroomen and White in this design?

DR: As the co-founder and Chairman of Cervélo, Phil White shapes the corporate direction of the company. In this project, the full engineering team defined the mission within this company direction, with the goals of being simply faster and bringing speed within reach. We had to respect the winning heritage of the P3, and help nurture Cervélo’s F1-style design process: performance always comes first. The description of the project management process that Mike provided earlier probably answers this question as well: as he mentioned, once performance targets have been met, we can understand the impact of changes to the form.

Trimes: What are some of the differences in the direction of the company since Cervélo is now under the ownership of PON?

DR: We’re really happy to be a part of the Pon Bicycle Group. Cervélo’s goal is to help our athletes go faster, so our strengths have always been in engineering and designing for speed. PON’s strengths in business organization and supply chain management help us improve delivery, sales support and supply chain operations. All these changes are for the better. There have been no changes in engineering staff, no changes in engineering tasks or scope, but improvements in our supply and delivery.

Trimes: There seems to be a slight difference is frame graphics since Cervélo is under new ownership. Was there a shift in Cervélo’s design philosophy? Are your responding to customer feedback? Are things pretty much business as usual?

DR: The graphic updates are in direct response to customer feedback and our marketing and product team. The new graphic packages began development in 2011 for the 2013 product line. This is independent of the PON acquisition.

Trimes: Cervélo seems still be hostile to offering multiple paint themes and an à la mode, stealth, nude carbon paint job.

DR: Unlike some bigger brands, Cervélo are still exclusive bikes. We don’t produce very many, and we don’t have that many part numbers. We try to keep the quantity of part numbers low for simplicity. Boutique brands with multiple colour options have a problem: the customer always seems to want the size and colour that’s not available. And each year we typically offer one or two Special Edition paint schemes, such as the World Champion painted P3 (commemorating Fabian Cancellara’s gold medal), the 2008 white with coloured “Olympic” rings version of the S3 or Thor’s red and blue Norwegian Nation Champion S3. These are typically only in quantities of a few hundred or less which makes them pretty unique on the road.

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