By Jay Prasuhn
With Shimano Ultegra Di2 6870 and ENVE SES 3.4 disc wheelset
I’ve documented the advent of disc brake-fitted tri bikes hitting the market (Diamondback, Cervélo, Parlee and, in prototype form, Cannondale), and we’re sure more are on the way. Yet that doesn’t even account for the awesome road bikes with disc brakes. Surprisingly though, only two are offering aero road bikes with disc braking.
Last fall, Cervélo revamped the S3, the progeny of the original Soloist, redesigning it for disc stoppers. Which was interesting; while most brands debut new technologies top-down, Cervélo passed on making a disc version of its top-line aero road bike, the S5, instead focusing on the S3: new tech debuted at a (relatively) mid-priced level.
The S3 has long been an unheralded bike in the Cervélo line. While we’ve enjoyed climbing the Santa Monica Mountains on Cervélo’s wispy light R5, and have spent years riding the stiff and aero S5 (ridden to a silver medal by Swiss ace Nicola Spirig at the Rio Olympic Games), the S3 was never attractive. It was a shade less aerodynamic than the S5, and not as light as the R5. It was a tweener.
Cervélo aimed to improve this jack of all trades; lighter, more aero, and with disc brakes, better at stopping. After a successful debut of the C-series mixed-surface endurance line, the S3 becomes Cervélo’s first road bike redesigned for disc braking. Suddenly, this tweener was akin to the girl in school with the braces and pigtails the boys picked on. You know, the one that grew out of the braces, dropped the pigtails and was again garnering the boys’ attention… but for different reasons.
The S3D borrows the long, ovalized tubes of the S5 and the clean little seat stays borrowed from the R5, and is dressed with price-conscious Shimano Ultegra Di2. The differentiator the S5 and R5 lack? Those Shimano 5805 hydraulic brakes.
I’ve been over it ad nauseam, but disc brakes are amazing: modulation, late braking, light touch, wet stopping—all massively better than rim brakes. The claimed aero drawback? Not so. Lack of a caliper mount point meant Cervélo engineers could also push the fork crotch upward, reducing the low-pressure zone behind the crown while widening the fork blade stance. Cleaner hydraulic cable routing further reduces drag. In the end, the S3D is claimed to be faster than its rim brake predecessor: Cervélo says it’s 19 grams (around 2 watts) quicker.
In practice, the later you can brake headed into a corner on disc brakes, the more you’re racing at speed. Stack enough of these reduced stopping experiences and you end up faster.
Cervélo says the redesigned frame also got stiffer (by 8 percent at the head tube and 9 percent at the bottom bracket) and shed some weight (40 grams) when compared to the S3 rim brake version.
We took the S3D up and down the hills of inland San Diego, then on the flat, fast roads north of Daytona, Florida. Max speed: 31 mph, much of that sustained in the drops, tongue dragging on the pavement behind a scooter while motor pacing. Another ride, 28 mph in a three-man rotation. Each ride averaged 20 mph in a town full of stoplights, and the S3D jumped at the opportunity to lead the group rather than sit in the draft. It simply wants to fly.
My previous personal daily driver was a Cervélo S5, so I was familiar with its stiffness as an aero road bike. The new S3 is immensely stiffer through the bottom bracket and, when closing gaps, in the head tube. The through axles add to how absolutely tied together the bike is front to back. Add ENVE hoops—the stiffest in the game in our opinion—and it adds up to a fun, straight-razor ride with sharp handling.
The S3D has two color ways on offer: red-and royal and a sharp white version with yellow accents.
To be clear, adding disc brakes pulls a bike previously considered mid-tier up, and the price reflects it. Like that girl in braces who grew up, stock rises. And there’s really just one comparable aero road bike available with disc brakes: the Venge ViAS model also specified with Ultegra Di2… and pricing at $100 more than the S3D. And consider: Cervélo’s own S5 with the same Ultegra Di2 spec prices $1,100 more than the S3D—and it’s a rim brake bike.
Triathlon application? It’ll take some massaging, but it can be done on the S3D. The bike ships with Cervélo’s own AB04 road drop bar with an aero top section that does not accommodate clip-ons. Just swap it for a round bar with a 31.8 mm stem clamp, and you’re clip-on ready with an aero setup for hilly races like Escape from Alcatraz or Ironman France.
Cervélo calls the S3D the company’s disc workhorse, but I see it as that and more; this is the bike you can ride every day, race on weekends in the local sprint… with exceptional stopping power. This is where the road bike battle will be fought: with bikes that can do it all. Welcome to the new world order.