Your Next Road Bike Will Have Discs

Long overdue, disc brakes are finally taking over the roadie world

Jun 7, 2016
Outside Magazine

Disc brakes are finally emerging on high-performance road bikes, including this model, the BH G7 Disc.    Photo: Inga Hendrickson

Almost two decades have passed since hydraulic disc brakes came to mountain bikes, and the technology is now ubiquitous on dirt. So it wasn’t a stretch to think that it would quickly make its way onto pavement as well, given the significant performance benefits over calipers. Discs take less force to decelerate, and because they offer greater stopping power and more refined braking, you can slow down later when cornering and feather the force for speedier descents. The migration took longer than it should have, though, in part due to technological hurdles—among them, integrating shifters and -hydraulics into the same mechanism on the handlebars—but also because of road cycling’s conservative culture. “There has been resistance to change from guys who have been riding a long time and feel like they know how bikes should be,” says J.P. McCarthy, a product manager at SRAM. “But the first time they go downhill with good brakes, it will change their minds.”

Indeed, the superior performance proved impossible to ignore. SRAM was the first to jump aboard, in 2013, followed shortly after by Shimano. Nearly half of the 33 road options we evaluated this year in Outside’s annual bike test had disc brakes—up from four a few years ago. And the UCI, cycling’s governing body, has approved disc brake testing on the pro tour in 2016. That means discs are finally appearing on high-performance steeds, not just the average Joe’s comfort bike.

BH’s G7 Disc, the first aero race bike with disc brakes we’ve seen, is the most innovative model of 2016. Conventional wisdom once held that the large surface area of the rotor would create too much drag for race bikes, especially ones meant to cheat the wind. Testing proved otherwise. “We found that when tucked in properly, and with the cables routed through the frame, discs don’t slow you down,” says Gene DiMenna, brand manager at BH. “You can brake later and carry more speed through turns, making you faster overall.” Our experience bore that out—this bike felt like a missile. The foil-shaped tubes scythe through the air, the bottom bracket is stiff for superior power transfer, and a complete Shimano Ultegra component group adds excellent value. Our only quibble was with the wheels: we would have preferred a deep-section rim to reap the full aero benefits.

Also intriguing is the Cervélo C5 Dura-Ace Di2. Though it’s ostensibly an endurance bike—with a tall headtube and slack geometry, a low bottom bracket for stability, and clearance for 30-millimeter tires—the whisper-light frame (a tick under two pounds) and top-of-the-line Shimano Di2 group set make it more capable than that moniker suggests. We admired its incredible stability at speed and comfort on bumpy fire roads, benefits of those wide tires, but the C5 was still light and quick enough to compete. And though it’s not yet approved by the UCI, this bike would make a perfect cobbles machine for the likes of Paris-Roubaix.

The Cervélo C5 Dura-Ace Di2 (16.6 lbs; $9,000).   Photo: Courtesy of Cervélo

The C5’s adaptability speaks to how disc roadies are starting to thrive off the tarmac as well. “Road biking is changing to a lot more multisurface riding,” says Dave Lawrence, road manager for Shimano North America. “Gravel, dirt, forest roads—people are trading in their old bikes for more versatile, disc-equipped models.”

Case in point: the Sage Barlow, a small-batch adventure bike that proves that titanium is the ultimate frame material for mixed surfaces. It pounded across slick rock domes and long passages of washboard while gobbling up vibration. “Can a bike really be this smooth on dirt?” raved one of our testers. The geometry is long and low, which made for comfortable all-day cruising and locked-in descents. We were completely content on our favorite gravel wheel and tire combo: Reynolds ATRs with tubeless Specialized Trigger 38s.

The Sage Barlow (20 lbs.; $7,640).   Photo: Courtesy of Sage

The award for most eccentric road bike of the year goes to the Cannondale Slate Force CX1. The tubeless 42-millimeter Panaracer tires mounted to 650B wheels, and a 30-millimeter lefty suspension fork, read more like mountain bike traits. There’s even a SRAM Force 1x11 drive-train, which we worried wouldn’t have enough gears for the road yet ended up working fine. But the drop bars confirm the Slate’s road intent. Riding on a 125-mile dirt and pavement loop in Vermont, we found ourselves dropping guys on lighter, stiffer, racier bikes all day long—especially on descents, where the Force disc brakes had us tearing around corners.

The Cannondale Slate Force CX1 (19.6 lbs. $4,260).   Photo: Courtesy of Cannondale

The Slate is an outlier, but it underscores the morphing road environment. “Are discs the future?” asks Lawrence. “Absolutely.”

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