The aero road bike’s current popularity has come thanks to Cervelo. While the statement, ‘Cervelo invented the aero road bike’, will be disputed by Kestrel, it’s hard to dispute Cervelo created the industry fire storm we see now. Aero bike after aero bike have hit shop floors - Specialized’s Venge, SCOTT ‘s FOIL, Felt’s AR1, and now Trek’s venerable Madone, the best known race bike in America, had been reinvented as an aero road bike. All the cool kids are going aero, and according to much of their own marketing, everyone is gunning for Cervelo.
Here’s the thing, they were gunning for the Cervelo S3. Launched in 2008, Cervelo had been developing that aero road platform for more than 2 years by the time they placed the all new S5 into the eager hands of Thor Hushovd at the 2011 Tour de France. The result was seven days in yellow and two stage wins. The rest of the industry appeared to be gunning for an outdated target.
Where the S3 saves approximately 20 watts over a standard road bike, the S5 saves another 10. What’s 30 watts worth? At 15 degrees of wind angle, optimum S5 conditions, a 160lb rider on a traditional road bike over flat terrain putting out 300 watts will do almost 25mph. Put that same rider and power on an S5 and he’ll do 25.5 mph. That is the difference between getting caught and staying away, whether it’s a club ride or the Tour de France. Aero road bikes are for real and the S5 appears to be the fastest, based on both Cervelo data and independent tests.An Aesthetic Vacuum
The S5 was designed in an aesthetic vacuum, no shape on the bike exists for form, it is all function. The resulting look is polarizing to say the least. We’ve had our test bike described as, ‘sex on wheels’, one moment and, ‘a barn gate’, the next. What Cervelo cared about was making an aero bike, not a pretty one.
That performance comes from the airfoil tubes and the skinny leading edge the bike presents. But that was all sorted out with the S3. What Cervelo wanted was an additional 100 grams of drag reduction and coaxing that out of the frame involved a top to bottom redesign. One concept, executed to the nth degree, seems to be responsible - shielding. Shielding is essentially hiding objects from the wind. It is a simple concept that is not so simple to design into an object like a bike. A lot of moving parts from different manufacturers, with a big sack of meat parked on top.
This shielding is most obvious at the rear of the bike and starts with the brakes. Instead of hiding the brake under the BB, which is undeniably fast, Cervelo opted for the more user-friendly seat stay position. By creating broad shoulders on the seat stays Cervelo was able to hide the break completely behind the airfoil section. The water bottles get this same treatment, hidden low on the bike, tucked behind a flared down tube. Like many aero bikes the seat tube has a large cut out to shield the wheel, but unlike most bikes Cervelo has extended this cut out as far as the brake bridge. Since the top of the wheel is spinning twice as fast as you travel the cut out becomes more important the more it extends.
Traveling forward on the bike we see evidence of more shielding. Up front the head tube is incredibly narrow and integrates cleanly with the fork crown. The low drag shape is complimented by a dropped down tube with only five millimeters of space existing between front wheel and down tube. To the wind it is a single shape and the turbulence typical behind the fork crown is eliminated.
To counter act an airfoil’s inherently poor lateral stiffness Cervelo utilizes their BBright system. At 79mm it’s not be the widest bottom bracket on the market, but it plays on the same principles. The bigger platform allows Cervelo to mate bigger chain stays to the frame. Something they have taken full advantage of with the S5’s massive drive side chain stay. It is also asymmetrical to take advantage of the real estate made available by the lack of non-drive side chain rings. The overall result is a bike 12% stiffer than the S3. Bigger tube shapes are not only stiffer, but they can be lighter thanks to thinner walls, but with the S5, lighter they are not. At almost 1300 grams for a 56cm the S5 is not a light bike. This is where the ‘VWD’ designation comes in.
‘VWD’ stands for ‘Vroomen White Design’, as in the founders of Cervelo, Phil White and Gerard Vroomen. These three little letters make all the difference for the S5. When Cervleo began making the R5 California, their sub 700gram boutique production frame, they learned an awful lot about advanced materials and new lay up schedules. Using powerful software called ‘Laminate Tools’ Cervelo is able to determine how best to use every gram of carbon. They know exactly how much stiffness adding even a grams of carbon to a specific area will deliver. While not made in California like the R5 Ca, the bikes bearing ‘VWD’ have benefited from these lessons. It’s not a magic new material, it’s not some breakthrough molding technique, it’s just a little better, a little lighter, a little stiffer across the board. All of these add up to a lot, 270 grams. Let’s be honest, saving 270 grams from a frame as heavy as the S5 doesn’t result in any mind-boggling numbers. The 54cm S5 VWD is 990grams. Good for an aero bike, nothing special for a road bike.
Good Legs and Playing Catch Up
Where those numbers do get special is on the road. Aero road bikes are not prized for ride quality. They can be a bit wooden, lacking the reactivity of a pure road-racing bike like the R5. While the S5 Team had previously impressed us with its ride quality in this respect, it is very good for an aero bike, the S5 VWD shocked us. Lively, spirited, reactive, the S5 VWD has the best ride quality of any off-the-shelf aero road bike. It has a better ride quality than the majority of pure road bikes. It’s that good. Don’t confuse that with compliance. It’s still a stiff race bike and if you ride an endurance bike you will find it uncompromisingly stiff.
The ride quality we are talking about is the spry feel it gives you when applying power. It reacts to big inputs, high speed attacks, instantly, as do a few other aero road bikes. Where the S5 is dramatically different is during low speed acceleration. Change tempo on a climb, jump from the group to get the club ride going, even pulling away from a stop sign the S5 VWD responds in a way that tells you, ‘Today, I have good legs.” As any rider will tell, that is a very good thing.
We don’t have a wind tunnel and we aren’t foolish enough to believe STRAVA can stand in for one so we won’t even go down the road about how much faster we rode. However big a difference half a mile an hour can make on the road, it’s still awfully hard to feel. That said, the S5 does feel awfully fast when the wind gets blustery, even pulsing a bit as the wind turns to the magic 15 degree yaw, the S5’s aerodynamic wheel house. Winds that would have had us shifting down, had us sliding forward on the saddle and hammering. Sure, it could all be in our heads, but the result was the same, we went faster.
But the biggest S5 surprise, maybe even the biggest improvement over the S3, isn’t ride quality or aero, it is geometry. The way the bike handles has been completely revamped. It is stable without ever being sluggish. Where the S3 felt as if you were riding above the bike, the S5 feels as though you are one with the bike, instinctively picking the right line and speed for every corner. They achieved this by looking to the R series for advice. The S5 has a slightly longer chain stay, top tube and head tube than the S3, but a head tube a bit steeper across most sizes. The result is magic.
This magic does have one downside. The taller head tube puts the rider in a more upright position, and with the rider being the biggest part of any aero equation, you can toss your precious 30watts out the window by sitting up proud. The S5 requires you to stay vigilant. Keep the elbows bent, stay in the drops, think about going a frame size down, and you’ll get the most out of it. You’ll also be a bit closer to those low-slung water bottles. They can present a long reach from the bars.
What the S5 VWD does is reward rider effort everywhere. On the front the aero pay off is huge, even in the field you save energy. The handling rewards your efforts pushing the pace on a descent or navigating a tight bunch. The lively ride rewards the climber and attacker, responding to tempo changes instantly. All of this adds up to a bike that is much more than a pure aero machine. Cervelo’s S5 VWD has set the aero bar even higher, reinventing the aero bike as a do it all road racer. Other aero road bikes will be playing catch up, literally.The Rider
You want your effort on the front, or off the front, to translate into more speed than any other bike. But you don’t want your effort on the climbs or in the corners to suffer either. You have flexible hamstrings and hip-flexors and run a slammed stem.
The Bottom Line
Price: $5900 (frame set) $9500 (as tested)
As Tested: 58cm Weight:15.7lbs (w/o pedals or cages)
Shimano Dura Ace Di2, 3T ARX LTD stem and ERGONOVA LTD bar, ROTOR cranks, Fizik Arione Saddle, Vision Team 30 alloy clinchers.More: cervelo.com