Read our review of the the Cervelo R3d disc brake road bike from Issue 55 of peloton magazine.
Disc brakes. There is no denying they have a place on a ’cross bike and they’re essentially mandatory for a gravel bike or backcountry explorer. When it comes to the pros, the spring classics are the obvious choice. Even after this year’s post-Paris–Roubaix ban, we expect to see them back very soon. But do discs belong on a grand tour thoroughbred? Bikes that live and die by stiffness to weight, by reactivity and efficiency? Cervélo, the owner of perhaps the greatest examples of this type of bike, believes they do.
The outrageously expensive, limited-edition bikes born of Cervélo’s Project California—the R5ca and Rca—are engineering equations come alive, stunning examples of stiffness-to-weight-ratio racers. What was learned during Project California has been applied to all Cervélo’s R series bikes, and for the first time, the grand tour-winning series has a disc option, the R3d.
The new R3d is R series tech through and through—from the Squoval-shaped tubes designed to be light, stiff and aero, to the well-known and race-proven BB-right bottom bracket. It possesses the carbon dropouts and carefully refined tapered steer tube that Cervélo calls “evolved steerer” design. Cervélo’s R series geometry is widely praised for its nimble feel, tempered by the need for all-day stability and comfort. Typically, disc brakes require a longer chain stay to ensure correct chain line, but Cervélo kept the aggressive 405mm stays by using a custom offset FSA crank and in the process retained the carefully crafted geometry of the R series.
But there are differences as well. The frame now hits almost 1,000 grams in a 56cm—light for a disc frame, but a far cry from the sub-700-gram Rca. Many of the other differences are very positive. Obviously, the braking is vastly improved and immune to weather, but the bike is stiffer too. Through- axles, and seat stays set wider thanks to the removal of the caliper brake, result in a 25-percent increase in stiffness at the bottom bracket versus a rim-brake R3.
The R3d still sits below the R5, and as such has a full Shimano Ultegra build with BR-RS805 calipers and dual 140mm rotors. FSA handles the cockpit with SLK post and stem and Energy Compact bars. The saddle is by fi’zi:k and the wheels are HED Ardennes—a great choice when many Ultegra-level bikes are going unforgivably cheap on wheels. The weight does not compare favorably to a rim-brake grand tour bike, 17.5 pounds, but it’s on par with other disc-road platforms.
We expected the R3d to lack the reactivity of the rim-brake R3, simply because of the weight, and while smaller riders, pure climbers, will acknowledge a lack of instantaneous response from slow speeds on steep slopes, bigger riders will actually gain more from the improved stiffness than they lose with the extra grams.
Despite the stiffness, the bike still gobbles up the miles with a smooth, forgiving ride, just right for a three-week jaunt around France. The braking is superb, with Cervélo’s fork eliminating the chop-and-rattle sensation under heavy braking that some lightweight disc forks create. With the confidence and lack of stress disc brakes provide in a tight peloton and down harrowing descents the benefits over a long day or three-week stage race will be profound, yet likely hard to quantify. The ride is just a bit calmer, and the peloton feels a little less hectic.
The extra time and effort Cervélo has taken to keep the R3d’s geometry identical to the rest of the R line is hugely effective. The bike feels like a racer, able to hit a tight apex, dash through a small gap and provide an aggressive cockpit for power delivery. If Cervélo stretched the stays to disc’s usual 415mm length, these feelings would be betrayed with a slower rear end and a long, endurance feel.
The Bottom Line
The disc battle will rage on—and this bike will solve nothing for those that spurn the technology—but for us it has shown that discs belong on more than ’cross bikes and gravel bikes, endurance bikes and rain bikes. A pure climber carving victory out of steep slopes and vicious acceleration may not ride one, but anyone craving the performance of a grand tour steed, with the confidence of discs, will find it in the Cervélo R3d.
$4,500; 17.5 lbs / 7.9kg (56cm)
Shimano Ultegra 6800, RS805 calipers, 140mm rotors, FSA SLK post and stem, FSA Energy Compact bars, FSA SLK cranks, fi’zi:k Antares VS saddle, HED Ardennes Plus GP disc wheels, Continental Grand Sport Race tires.