Cervelo RS

By Tom Demerly.

When Porsche unveiled the Type 970 Panamera 4 -door at the Shanghai Auto Show in 2009 I was outraged. A four door from Porsche? It’s like Ferrari making pick-ups trucks.

I felt the same way when I heard of Cervelo introducing a sport-touring model with the RS. Cervelo is born in racing; advanced composite engineering and Tour de France stage wins. Not the “Duffer Donut Ride”. I didn’t see where a non-race bike “fit” with Cervelo.

What I didn’t understand about the Cervelo RS is that it’s aimed at an expanding group of performance riders who are pragmatic about what they need- and don’t need. The fifty-something engineer, the guy who raced cat 2 in college twenty years ago, the endurance rider crossing the country in a month, the emerging Brevet, audax or Randonneur cyclist. These riders are athletic, fit (or trying to get fit), understand performance and won’t settle for a “duffer” bike. In short, this rider wants long-haul performance that provides comfort so they can focus on their goals. Another thing I missed about the Cervelo RS is the bike actually is a race bike, with an impressive palmares that includes classics like Paris-Roubaix.

“(The RS is for) …long-haul performance that requires enough comfort so a rider can focus on their goals.”

I get it now: BMW 7 Series, Porsche Panamera, Mercedes C300. The automotive analogies translate for me. But could a racing company make the translation from pure racing machines, where Cervelo started, to the sport-touring category?

To answer that question it’s important to understand what sport touring is- and is not. Sport touring or Randonnee bikes are not just road bikes with taller head tubes and more flexible frames. This category has gotten a bad name with racers because many of the entries are watered down race bikes with higher head tubes and wider saddles built on mamby-pamby carbon lay-ups that feel like over cooked pasta. That category leaves me cold, and includes an increasing number of high-head tube bikes that are condescending to the rider who understands fit, performance and geometry, and not very useful to the entry level rider- especially in the long run.

The best models in this category aren’t entry level. The pragmatic cyclist eschews testosterone in favor of intellect and understands this category is a better performance choice than a low-head tube, steep angle racer for a performance bike. These bikes are for any rider who has learned the path to performance is paved with comfort, especially when the path under their wheels is barely paved.

Randonnee bikes are not just higher head tube bikes, no more than a BMW 7 Series is a two seater with a bench crammed in the boot.

“Randonnee bikes are not just higher head tube bikes, no more than a BMW 7 Series is a two seater with a bench crammed in the boot.”

As with all Cervelo design projects, Cervelo RS is a product of engineering evolution and innovation. The RS is a natural choice for Cervelo since no bike brand mastered the category in the North American market except for hand builders in titanium and cro-moly. Most of the U.S. riders competing in European brevets like Paris-Brest-Paris use custom bikes because nothing like the RS was previously available in North America from the larger brands.

An example of how not to build higher head tube bikes resides in the minutiae of Trek’s geometry charts for their Madone 4 Series and Madone 6 Series bikes. I love Trek’s low head tube Madone 6 Series bikes. I will argue the 4 series is a watered down version with the same geometry but with a 3cm higher head tube tacked on. While that works for a big Trek dealer, it isn’t the solution for a rider who wants higher handlebars- neither is adding 3cm of spacers on a Madone 6. This is more an economic accommodation at the manufacturing level than an engineering solution to the customer driven design challenge of higher head tubes.

The head tube, top tube, down tube union of the RS also acknowledges the need for unique engineering solutions on a high head tube bike. Cervelo uses “Front Boomerang” construction on the front of the bike. Front Boomerang means the head tube, down tube and top tube do not start life as separate tubes- they are one unified, molded piece. This enables engineers to extend the carbon fabric over these frame members, adding lateral stiffness and improving vertical compliance for comfort. You can’t do this with separate tubes so the front end of a Cervelo RS is one piece of engineered carbon fiber.

The frame set goes on to reveal a long list of engineering details fine enough that you may miss them until you compare the ride to other bikes- that don’t have them. The fork blades have a subtle curve to moderate road shock while maintaining steering authority- the theme of the bike: Comfort and control. Contours of the frameset become more conspicuous when you look close- transition from squoval to round on the seat tube, the gossamer weight derailleur mount, the hefty bottom bracket shell. These are all details you may notice on the sales floor or on the website, but will appreciate during the long miles. It is, a bike of engineering details.

As the handlebars get higher more of the rider’s weight is shifted onto the back of the bike. The back of the bike has to change also, with slightly longer chainstays and a more stable head tube angle. The other brands don’t make those geometry changes from their low head tube bike to their higher head tube bikes. From the low head tube Madone 6 to the higher head tube Madone 4 Trek only changes the head tube. In a 54cm frame size the Madone 6 and Madone 4 both have a 73 degree head tube. The Cervelo RS in size 54cm has a 72 degree head tube for greater stability. Cervelo also added a scant, but critical, 5mm to the rear center dimension for better support of rider weight on the rear wheel. And finally, Cervelo made a major change to the design of the RS rear triangle.

The seat stays on the Cervelo RS are bowed slightly, creating a leaf spring effect that works well with the longer rear/center measurement of the bike. This accommodates having more weight on the rear wheel by adding comfort to the back of the bike.

This configuration, along with the specific lay up of the Cervelo RS, was designed using Cervelo’s CETOP or “Composite Evaluation Tube Optimization Program”, a finite elemental analysis tool developed by Cervelo to design the frame’s unique geometry, design and material configuration, especially the subtle refinements in the RS. The features controlled in CETOP include frame geometry; tube shapes and the layup of the carbon fiber in the molds.

“As the handlebars get higher more of the rider’s weight is shifted onto the back of the bike. The rest of the bike has to change also, with slightly longer chainstays and a more stable head tube angle.”

The Cervelo RS accomplishes design goals through engineering, not gadgetry. Specialized makes “ride quality” road bikes by adding weight and material with their “Zertz” inserts. Cervelo improves ride quality by removing weight with their lightweight, curved seat stays. It recalls the Saint-Exupery quote, “Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away.”

Cervelo tag lines this bike as “Your best entry in to pro bike performance”, but I’ll suggest this is also a bike you graduate to after decades on low head tube, tight steering crit bikes. And frankly, after years of subordinating comfort to performance, you deserve the RS. It may be a great bike to start with as a high end road bike, but it’s more likely a great bike to wind up on after you’ve been on everything else.

“It may be a great bike to start with as a high end road bike, but it’s more likely a great bike to wind up on after you’ve been on everything else.”

An interesting engineering detail of the RS is the range of frame sizes, especially at the small size. The so-named “XS” size Cervelo RS may be the single best offering for short male and female riders in the industry. Other bike brands have done some strange things to make small frame size road bikes that include not really shortening the reach dimension. The bikes got vertically smaller but never got horizontally shorter. Unless you had arms like an orangutan the reach dimensions were too long. If you put an 80mm or shorter stem on the bike the steering became too responsive. The XS size Cervelo RS really is a proportionately smaller bike. The effective reach is decreased with the wheelbase, maintaining good geometry including the 72 degree head angle and 73 degree seat angle. The bike also uses 650c wheels front and rear, a thoughtful (and expensive) engineering feature. While 650c wheels do provide minor logistical challenges when buying tires and tubes, these are overwhelmingly outweighed by the fit and performance advantages of keeping the size of the wheels in scale with the size of the frame and rider. One of those advantages is no toe clip overlap even on the very small frames. Most performance road bikes do have toe clip overlap, where the front tire can hit the rider’s foot when the handlebars are turned. It isn’t unusual or dangerous for a skilled rider. For a new rider it can be alarming. This is another strong case for using 650c wheels on the smallest frame size RS. For small riders, being on a 700c wheel bike is a like a person in size 5 shoes wearing size 10’s. They don’t fit.

A final geometric feature of the RS is that it works very well for small females as well as males. There is no version with flowers painted on it but it may well be one of the best suited “female” bikes available since it does change size proportionately the same way living people do. Most so called “Women Specific” bikes fall apart when you read the geometry chart and notice that a very small frame size has a disproportionately long top tube. Especially on the smallest “XS” size Cervelo RS the 650c wheels enable Cervelo to build the frame with a short top tube and short wheelbase that match a shorter rider’s dimensions. There is a separate parts suggestion from Cervelo for the gender specific RS.

“The Cervelo RS accomplishes design goals through engineering rather than gadgetry.”

The complete 2011 Cervelo RS bike comes with a spec suggestion list from Cervelo that includes SRAM Rival, FSA brake calipers- which I like because of alloy barrel adjusters (not plastic). The furniture in the component suggestion list is a great Fizik Pave saddle on a 3T Dorico Team seatpost with an easy to use two bolt adjustment head. Cockpit is an FSA Omega Compact drop bar and OS-190 LX four bolt, front plate stem. The wheels are Shimano’s R-500 rolling on Vittoria Rubino Slicks, which I have always criticized as being fragile. Wear ‘em out, buy some Continentals.

Price for the 2011 SRAM Rival version is $2600 USD while the previous model year version with Ultegra was a full $1000 higher at $3600. That makes the $2600 RS for 2011 even more attractive.

The spec suggestion list for 2011 is good, especially the drivetrain with detail suggestions like the 12-25 cogset and 50/34 compact crankset, perfect gearing for this bike. I like the seatpost to match the bar and stem mostly for appearance sake, and in this case I would have liked to see an FSA seatpost in the spec suggestion. That said, Cervelo’s component recommendations are exactly that- a recommendation. The specifications on complete bikes may change during the season with the ebb and flow of component supply. Customers are sometimes flummoxed by this, but I’ll side with Cervelo that specification changes need to be “suggestions” that change with equipment supply. In a given shipment of 10 Cervelo bikes the component specifications may vary slightly, and that is normal, so Cervelo is careful to refer to their component specification lists as “recommended” since they are subject to change.

How does it ride? The difference from my favorite bike (of any brand), the Cervelo R3, is noticeable. There is a lot of head tube. You sit upright. The rear end is quiet and civilized. Since the RS is not a BBright bike like the R3, the frame is an order of magnitude more tame. This bike does not breathe fire. It whispers polite commands. Steering is excellent. I thought of automotive racing, touring car analogy and it is absolutely descriptive. It is alert enough for a spirited group ride but tame enough for the long cruise. Above all, it is simply more comfortable. You feel the bumps less, it takes less effort to go straight. For a rider who is more or a realist than a Lance wannabe, this is a logical, well researched choice. The Cervelo RS is a bike for grownups who know what they need to ride the way they want to ride.