Two years ago, while on a ride that took in some of Malibu’s most fearsome descents, I had a conversation with a product manager from one of the big three bike companies. The occasion for both the conversation and the ride was a piece I’d just published about carbon clinchers, but as these things often do, talk turned farther afield and we landed on the issue of disc brakes. I can say that at that point in time I was flat-out not in favor of disc brakes on road bikes.
What happened next can only be described as a debate. I would state an objection or concern, and he’d knock it down. I started with frame design. There was the fact that forks would have to be completely re-engineered to handle the braking forces. He said their engineers were already well-versed in the software that would help them with new designs.
As SRAM and Shimano had yet to unveil either of their systems, and I thought we were still more than a year from seeing a hydraulic system from either manufacturer, so I hadn’t seen their lever designs that incorporated the master cylinder into the lever, which gave me the opportunity to wonder just how one would be incorporated and where it would go. “They’ll figure that out,” he said.
We talked about weight and how disruptive that would be to the pursuit of the 13, 12, 11-pound bike. He noted that since the introduction of disc brakes in mountain biking, the weight of cross-country systems had been cut nearly in half. Even downhill systems had gotten lighter while modulation and power had improved. He also pointed out that rim designs could evolve once we could eliminate the brake track and reducing rotating mass would make the bike easier to accelerate. I was chastened to think how right he was that it would be better to have the mass, whatever mass there was, closer to the hub, not further from it; every cyclist knows that.
I noted how the flex pattern of both the fork and the rear triangle would change with the addition of more carbon to handle the braking forces, changing the ride of the very bikes those engineers had just worked so hard to make so light and ride so well. It seemed the very definition of antithetical. Again, he said, their engineers had software that would allow them to restore that ride quality by shifting material placement so that frames wouldn’t turn into jackhammers just to make sure they stopped.
I threw everything at him I could. I even tried braze-ons and aerodynamics. At a certain point he said, “Fundamentally, it’s just an engineering problem.” He summed it up as, ‘You give engineers a target and they figure out how to hit it.’
Then he lobbed the big bombshell. He predicted that we would see brakes in production and being spec’d on a few exotic bikes by 2014; many top-of-the-line road bikes would have disc brakes by 2015 model year and that the majority of higher-end road bikes would have them by 2016. Given that he was the head of product management for a big bike company and privy to meetings with Shimano and SRAM that I wasn’t, any counter arguments I might have wanted to make would have carried all the logic and factuality of an evolution denier. I’d have been shouting, “Because dinosaurs!”
I kept rolling that one statement over in my head as we climbed—it’s just an engineering problem. It was remarkable in its power. It reduced the problem to math, which I found not just compelling, but alluring. Rather than seeing this as a way bikes would be ruined, it turned the problem around into something I was curious to see unfold.
Fast forward two years and I’ve now done a fair number of miles on the SRAM hydraulic system, TRP’s mechanical Spyre and some on Shimano’s hydraulic system. I’ve come to a few conclusions about disc brakes.
They can be summed up thusly: I like them and want them.
I know that not everyone shares that outlook, and for some, the issue is the potential for injury.
I was on a ride recently where I heard a rider saying he’d never ride a road bike with disc brakes because he didn’t want to get sliced up by the rotor in a crash. That’s not the first time I’ve heard that concern. While it’s true that I’ve heard of people cut by rotors, the injuries in the vast majority mountain bike crashes don’t include damage done by a rotor Ginsu-ing its way into flesh. Most crashes simply don’t involve body parts going into the wheels. Consider how often people are injured by chainrings in crashes; they occupy a far more exposed space than rotors do. RKP contributor JP Partland told me he knows a rider—exactly one rider—who lost a finger when it went into the spokes of a spinning wheel during a crash. Let’s call that an exception. Odds are, should you crash in the future, you’re much more likely to lose skin or break a collarbone than suffer a burn or cut due to tangling with a rotor.
The manufacturers of disc brakes like to talk about how disc brakes offer greater power. It was a handy talking point when they were new to mountain bikes. Honestly, it’s a lousy line when talking about road bikes. No one complains about not having enough braking power, and being able to brake from the hoods with a single finger isn’t enough of an improvement to make most people jump ship.
Where I’ve noticed discs make an enormous difference is in modulating braking power. There are a number of rim calipers that offer a very progressive brake response. By that I mean that initially, they do very little, and then the power comes on rather suddenly and ramps up quickly. This only gets worse when you inject many (but by no means all) carbon clinchers into the mix. What’s far more preferable is to have brake power come on very gradually so that you can adjust your braking as conditions require.
I’m aware that most of the world is on the flat-ish side, that mountain descents aren’t a part of every rider’s daily experience. As a result, I’ve heard riders talk about how they simply don’t need that much brake power. And it’s true; in an absolute sense, I don’t need all the power that disc brakes present when I’m riding in Memphis. However, Memphis (and most of the world) has two things that make disc brakes really handy: rain and mud. The mud isn’t a big deal if you don’t ever plan to ride your bike on an unpaved surface, but I’ve always liked doing that, and unless you live in California, where rain has been outlawed by God, you know how in the rain brake performance becomes as ineffectual as an honest politician.
The other really compelling detail for me is how once you add disc brakes to a road frame, tire size becomes virtually unrestricted. The hottest area of tire development right now is in the arena of wider tires for the road, particularly treads for mixed surface use. Exploring this is as fun as walking a record store with a gift certificate used to be.
In a world full of marginal improvements, I’ve come to appreciate that discs present a real evolution in braking for road bikes, one that I was hesitant to accept at first, but now embrace. We’ll look back on this era the way we used to look at the early high-performance clincher tires, as a better technology, one that will improve with time.