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Stopping progress? The debate over hydraulic disc brakes in the pro peloton

  • By Caley Fretz
  • Published Aug. 13, 2014
  • Updated Oct. 31, 2014 at 6:13 PM EST
Are rim brakes' days numbered? The industry agrees that it's only a matter of time before discs become standard on road bikes. Photo: Brad Kaminski | VeloNews.com

(Editor’s Note: This article previously ran in the August issue of Velo magazine.)

It’s misting in Belfast; it’s wet everywhere, but not quite raining. Water oozes out of the air and condenses on Garmin-Sharp’s boxy mechanic truck, on the bikes leaned against it, on the tools, and on the broad shoulders and black and blue Park Tool apron of the team’s head mechanic, Geoff Brown. He is poking and prodding at one of the team’s Cervélo time trial bikes, bleeding a hydraulic rim brake.

His team is about to set off on three days of wet racing through Northern Ireland and Ireland, the first stages of the Giro d’Italia. The conditions are, and will be for much of the first week of the race, ideal for disc brakes: wet, cold, and hilly.

But Brown doesn’t want discs in the pro peloton, not now, and maybe not ever.

“I have nothing against the technology,” he said, squeezing hydraulic fluid into the bike’s brake levers, already very much at home with the bleed process that hydraulic road discs would bring with them. “I think the technology is absolutely, 100-percent correct. It works, it’s proven, it’s great. It’s just not an appropriate technology for this application, not for our kind of bicycle racing.”

There are more questions than answers in the road disc debate, with as many opinions as there are riders, mechanics, team owners, bike companies, and engineers. The technology sits in a woolly expanse between the absolute truth of its technological superiority and the absolute truth of its inadequacies and challenges. It is simultaneously one of the most exciting new technologies in road cycling and one of the most frightening, even dangerous.

Whether disc brakes belong in the pro peloton, well, that depends on who you ask.

More questions than answers

Brown’s opinion is common in the pro cycling world, his criticism aimed not at the technology itself, but at its application within pro road racing in particular. Many feel that discs simply don’t belong, and their arguments are many: They are too heavy, or not aerodynamic enough; they’ll slow down wheel changes and are unnecessarily dangerous in big pileups.

Few argue that rim brakes are superior, or even equal to, disc brakes in pure stopping performance — power, modulation, and consistency are all clear advantages of discs. But arguments based on the specific logistical and safety requirements of road racing do hold water.

Safety is a genuine concern. Disc rotors are sharp, like spinning knives that have been heated in a 500-degree oven. They can easily slice flesh, and will burn on contact after a hard stop (“at least you’ll get cut and cauterized at the same time,” Brown joked).

Riders are understandably concerned, as it is their flesh that is on the line. For Garmin’s Nathan Haas, safety is the only factor that really matters. “Do you know how hot a disc brake gets under braking? If you crashed on one with your face, your face is going to melt,” he said. “Keep it out of the sport. It doesn’t belong. Just don’t do it.”

Disc brakes increase aerodynamic drag and add weight, somewhere between 100 and 300 grams, depending on the frame, wheel, and brake manufacturers in question. If the additional braking power and improved modulation are not truly needed — and many say they are not — then these drawbacks exist without a real upside.

Then there are the logistical concerns. An industry that has never been particularly good at setting standards, or sticking to them, would need to come together to decide on a few key points — things like rotor size, whether to use thru-axle or quick releases, even basics like hub width. Without such standards, neutral wheel service would be impossible.

Even with such standards, wheel changes will be slower. A few seconds can make or break a race, so both racers and mechanics are understandably concerned. New thru-axle designs, which lock in place with single motion, similar to a normal quick release, could help alleviate this problem but will never eliminate it entirely.

Discs would change road racing, of that there is no doubt. But plenty of other technologies have done the same in the past — aero bars, deep-section wheels, clipless pedals, indexed shifting. Change itself need not be feared; change for the sake of change, on the other hand, is more suspect.

Amateur hour

The world’s best cyclists can’t always ride the world’s most technologically advanced bikes. What’s even stranger is that some don’t even want to.

Technology in sport tends to be led from the front. Traditionally, top riders act as guinea pigs for the rest of us, testing and proving equipment at the highest levels before it trickles down into the realm of the mortals. High-profile professionals are key to the marketing efforts of their equipment sponsors, helping to move new and innovative product.

Road discs, and the sport’s governing body, the UCI, have reversed the flow. The technology is trickling upwards, from the amateur realm, and from the dirt, to the upper echelons of road racing.

The opinions of professional racers are distinctly mixed, and without any clear demarcation. One might assume that younger riders, or those originally from mountain-bike racing, would be keener on the new technology. But there is no consistent distinction.

“I’d love to have road discs some day,” BMC Racing’s young climber Peter Stetina told Velo; his opinion was opposed to that of Garmin’s equally young Haas. Among the old guard, Fabian Cancellara (Trek Factory Racing) couldn’t care less about discs, while Tom Boonen (Omega Pharma-Quick Step), an avid motorsports fan, is in favor.

Even those professionals in favor — riders like Stetina and his BMC teammate Taylor Phinney — aren’t putting any real pressure on the powers that be to bring discs into racing. There is no organized push from riders to force the UCI into allowing disc brakes.

Despite a vocal opposition and somewhat tame advocates, the move to discs is coming. Why?

“The people actually buying bikes, they are the ones who are interested in discs,” said Trek’s road product manager, Michael Meyer, whose product line includes the Domane Disc 6.9, a disc-brake version of the bike on which Cancellara won the Tour of Flanders.

That interest, at least for now, is mostly in non-racing applications. “We don’t see a big demand for a race bike with disc brakes in the marketplace,” said Meyer. But that could change, particularly if the pros began using the new technology.

Consumer interest translates into brand interest. Brand interest equates to sponsor interest, particularly in this age of endemic team sponsors. Sponsor interest results in team adoption, however begrudging that adoption may be.

The opinions of the riders, mechanics, and the rest of a team’s staff have little to do with the decision. These teams exist to sell brands, and sell bikes, and if the industry believes that consumers want discs, that’s what they will be given, on a podium and wrapped in a yellow jersey.

Will it happen this year? Or next? No, said Meyer, and other industry insiders polled by Velo unanimously agreed.

“I don’t think the technology is there yet,” Meyer said. “I don’t think the racers want it, at least until the technology is perfect and there’s compliance across all three platforms. [The UCI] needs to make a calculated decision. Until it’s dialed on our side, I don’t think they can make a decision on their side.”

It is coming, though

The UCI will run Paris-Roubaix as a road disc test event in 2016, according to sources within the UCI and the cycling industry. The governing body was originally shooting for 2015, but Campagnolo’s slow movement toward discs and SRAM’s recent recall moved that optimistic timeline back. Even 2016 may be overly optimistic. “If the answers aren’t here today, I don’t think the UCI is a year or two away,” Meyer said.

The UCI, and in particular its new technology officer Dimitris Katsanis, has made it clear that it believes that a wholesale swap is the safest route, when the technology is ready. This would prevent riders from running into each other due to a huge disparity in braking power, especially on high- speed descents.

Professionals seem to be on board with this approach. “I think it’s something you have to do all at once, to make sure everyone is all on disc brakes. Not so much in the dry, but in the wet … it changes a lot of ability to brake, to slow down,” Phinney said.

Teams already use special bikes for Roubaix, so using the Queen of the Classics as a test event makes economic sense for sponsors as well. And Roubaix is flat, so overheating is not a concern. It’s a safe place to bring discs into the WorldTour.

After Roubaix, the future is murky. These same debates surrounded the adoption of discs in mountain bike racing in the early 2000s, and discs definitively won that battle. One has to believe that the superior technology will win out; the best riders in the world should be riding on the brakes that stop them best. The logistical hurdles are just that: hurdles, ready to be jumped. The cycling industry is full of engineers who are, no doubt, eager to do just that.

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Caley Fretz

Caley Fretz

Tech Editor Caley Fretz can usually be found chasing races along the backroads of Europe or testing bikes and gear in the mountains outside Boulder, Colorado. If you can't find him there, check the coffee shop across from VN World Headquarters.

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