By matt phillips
The Disc-Brake Equipped Cervélo R3 Disc Ultegra
A little late to the party, but worth the wait
Cervélo gets credit for popularizing aero road bikes. Although the company was on the forefront of that trend, it’s been a bit slow to pick up another: disc brakes for road bikes. This changes with the arrival of the 2016 R3 Disc.
Cervélo’s race-inspired R-series consists of four bikes: the R3, the R5, the least-expensive R2, and the ultraexclusive RCA. Phil Spearman, Cervélo’s senior product manager, explains that the R3 was picked to be the first Cervélo disc-brake bike because, “We wanted it to be accessible. The 3-series still represents the most well-known and recognized models in our family, so it was clear that we needed to offer our first disc race bike there.”
The R3 and R3 Disc share geometry and the main triangle’s tube shapes. Called Squoval (squared oval), this series of shapes is intended to be light and stiff first, with some aerodynamic benefit. Beyond that, the frames diverge.
What You Need to Know About the Cervélo R3 Disc Ultegra:
• Same geometry as R3 with rim brakes
• Mid-aero frame shaping saves a few watts without any weight or stiffness compromises
• Improved braking performance and no aerodynamic penalty
• The latest in disc-brake tech: flat mount calipers and thru axles front and rear
There are the brakes, of course. Cervélo chose the low-profile flat mount standard that is specific to road bikes, though the rear triangle was designed to be, “retrofit compatible for virtually all disc brakes and adapter mounts. At least, every one that we could find at the time,” said Graham Shrive, Cervélo’s engineering project manager. Without a rear rim brake or seatstay bridge, Cervélo’s seatstays look ethereal. According to Shrive, “the seatstays are precisely the UCI minimum, one centimeter [in diameter]. We would go smaller if they would change that damn rule.”
Aside from the brakes, the most obvious change is the adoption of thru-axles: 12x142mm rear, 12x100mm front. Spearman explains that thru-axles allowed the engineers to change the way the rear triangle was manufactured—unlike the R3 for rim brakes, the R3 Disc’s rear triangle is manufactured as one piece, and thus stronger and lighter. The weight savings was poured back into the frame to increase the bottom bracket stiffness by 20 percent, “since we designed this to be an option for [our pro] teams.”
Not only is the fork updated for disc brakes and a thru-axle, its bow-legged stance differs from the fork shaping on the rim-brake R3. Disc brakes are generally less aerodynamic than rim brakes, but the switch to discs here allowed Cervélo’s engineers to reshape the R3 Disc’s fork in ways that make up some of the aero deficit. Coupled with the removal of the rear rim brake, seatstay bridge, and other tweaks, the R3 Disc matches the rim-brake R3 in aerodynamics. “While the R3 [Disc] loses out a little bit at zero yaw [angle], it sees an increase from the [nondrive side]. The weighted average works out to be null,” said Shrive.
Claimed frame weight of the Cervélo R3 Disc Ultegra in 56cm with paint and hardware is “sub 1,000 grams,” which, though very vague, is the same as what Cervélo claims for the nondisc R3. Usually when companies claim “sub 1,000 grams” it means the frame weighs 990-ish grams, with a bit of head room for production variations so the Internet doesn’t scream, “I weighed my frame on a cheap, imprecise scale and it weighed 1,001 grams. Everyone lies!”
The Disc’s fork is 50 grams heavier than the rim-brake fork. Said Shrive, “This was largely due to the decision to place the cable-hose exit on the truncated trailing edge in order to maximize the compatibility with all possible systems, but this clearly creates a challenge from a strength perspective.” In other words, the fork had to be reinforced with more material.
At $4,500, the Cervélo R3 Disc Ultegra is, in today’s market, solidly a midrange bike. It’s nicely equipped for the money and comes in at 17.3 pounds, which is reasonable for a disc brake bike. It’s built with a Shimano Ultegra 11-speed mechanical drivetrain and Shimano’s high-end hydraulic disc brakes, with BR-RS805 brake calipers and ST-R685 levers. I could niggle here or there about hood length and shift-lever throw, but overall shifting and braking performance is tops.
I think how good these disc brakes are bears repeating. A Shimano Dura-Ace/Ultegra/105 rim brake is great—all that I and a lot of people need in a lot of situations. But Shimano’s hydraulic disc brake kicks the shit out of the company’s very good rim brakes. They have better control, and more consistency. Ride discs for a while and then get back on rim brakes and you'll find yourself saying, “Whoa, what’s wrong with this bike.” And in rain, forget it. It’s like comparing the opening weekend take of a Wes Anderson movie against a new Star Wars.
The wheels are Hed Ardennes Plus GP Disc, which have a wide rim that puffs the Continental Grand Sport tires out from their published 25mm width to almost 27mm. Bar, stem, and seatpost are mid-tier Full Speed Ahead product, and the saddle is a Fi'zi:k Antares Versus, with relieved center channel.
The Cervélo R3 Disc Ultegra has 405mm-long chainstays like the rim-brake R3, but uses a 135mm spaced rear hub (rim-brake wheels are 130mm). According to the drivetrain makers, the 405mm stays and 135mm hub combo is a no-no because it screws up the chain line, which degrades shifting performance. Cervélo addressed this by using the disc-brake version of FSA’s SL-K Light BB386EVO crank, which shifts the chainrings 2.5mm outboard to achieve the approved chainline. This is the crank our review bike was equipped with, and shifting performance was flawless.
However, the q-factor of the disc-brake cranks increases 2.5mm per side (5mm total), which doesn’t seem like much but is enough for the q-factor zealots to lose their minds—and share their thoughts with Cervélo.
So, Cervélo made a running spec change and uses the nondisc, narrower q-factor. When asked if shifting performance suffers, Spearman said, “When we tested the standard FSA SL-K 386EVO, we found that the shifting was well within current acceptable norms when riding in cross-chain conditions (i.e. no chain catching/grinding in 36x13). FSA has validated this, and we are really happy to be able to make this change.”
Aboard the R3 Disc Ultegra, I experienced a curious combination of sensations. Like the other disc road bikes I’ve ridden, it feels overbuilt, slightly sluggish, a bit over-stiff, and a touch numb. I’m probably projecting, but the R3 Disc feels like no chances were taken, and the designers erred on the side of conservative caution. I suspect that, with time and evolution, disc-brake road bikes will lose this feeling and start matching the liveliness of today’s rim-brake bikes.
A happy result of its overbuilt-ness is that the R3 Disc is very stiff, particularly at the bottom bracket. The frame is mostly capital “S” solid: The front end is stiff, but feels a little softer than the rear of the bike. Still, it corners accurately and is resolute when darting though traffic or sprinting over a rise.
At 17.3 pounds, the Cervélo R3 Disc Ultegra is not heavy, for a mid-range disc road bike. But it feels heavier than its actual weight. It accelerates a bit more slowly, and the handlebar swings more heavily that I would expect. I’ve noticed this sensation in other road-disc bikes, and I have yet to nail down the cause. My suspicion is that with disc-brake bikes, the weight is distributed differently than a rim-brake bike of a similar weight, and that’s what I’m feeling: that difference between what I’m used to (rim brake bikes) and what’s newer to me (disc brake bikes). Different isn’t worse, or slower; it’s just different.
But remember how I said the Cervélo R3 Disc Ultegra is a curious combination of sensations? Though it doesn’t feel particularly quick, the R3 Disc does feel fast. I’ve spent a lot of time on good aero road bikes, and jump back and forth between them and regular road bikes. I feel the difference. It’s subtle, like the feeling of picking up a tailwind, except all the time. I don’t think I’m crazy, as most people who have given a good aero road bike a real try (not just a spin around the block) notice the sensation or something similar. The R3 Disc has this feeling; it’s as though once the bike is up to speed, it is easier to hold it there, and to go faster.
Cervélo’s R-series bikes are primarily designed to be light and stiff, with some aerodynamic tuning. But they’re not aero-first bikes, so I don’t believe what I was feeling was totally aerodynamics. Maybe every time I rode it I was well-rested, or the wind was the right direction. But though it feels a little slow to accelerate, once it gets going, it felt just noticeably faster than the average, non-aero road bike, which seemed to be confirmed by my stopwatch.
The Cervélo R3 Disc Ultegra has an interesting ride feel. Generally, it’s quiet—almost silent—smooth, and damps vibrations and shocks well. It almost feels dead, right on the edge of flat and uncommunicative. When bigger bumps are encountered, the frame doesn’t have a lot of leaf-spring-like vertical give. However, much of the shock is damped out, so the bike bounces and kicks from hitting bigger bumps but without the sting that typically accompanies them. Installing bigger, lower-pressure tires improved the vertical compliance; Cervélo says the bike is designed around 25mm tires, but I was able to fit some healthy 28mm tires with room to spare.
The Cervélo R3 Disc Ultegra is a typical Cervélo. Though it is late to the disc-brake party, it’s well-thought-out, light, has aerodynamic flourishes, and is intended to be a high-performance bike. It certainly has the speed, handling, and braking to hold the Cervélo cachet, and does so with a midrange price and excellent parts.
Cervélo R3 Disc Ultegra Specification
Name:R3 Team Ultegra
Built by: Cervelo
Available Sizes 48 51 54 56 58 61 54 56 58 54 56 48 56 54 56 58 54 56 58 54 56 58 54 56 54 56 58 56 58 51 54 56 58 61 51 54 56 58 56 61 54 56 58 54 56 58 54 56 58 54 56 58 56 58 56 58 54 56 58 54 56 54 56 58 54 56 56
Bottom Bracket BBright
Brakes Ultegra BR-6700
Cassette Shimano Ultegra CS-6700 12-25T
Chain Ultegra CN-6700
Cranks BBright 50/34T
Frame Weight 950
Front Derailleur Ultegra FD-6700
Front Tyre Vittoria
Front Tyre Size 700x23C
Handlebar Ergonova Team
Headset Type Orbit IS-2 integrated
Rear Derailleur Ultegra RD-6700
Rear Tyre Vittoria
Rear Tyre Size 700x23C
Seatpost Palladio Team
Shifters Ultegra STI Dual Control ST-6700
Stem ARX Pro
Weight (kg) 7.4
Weight (lb) 16.31
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