'Hot burning knife blades on our wheels' – The controversial story of disc brake adoption in the peloton, 10 years on

Imagine for a moment if Tadej Pogačar had rolled up to the starting line at the 2026 Tour de France sporting a bike fitted with rim brakes. It would become headline news worldwide and likely cause every cycling forum on the internet to go into meltdown.

Yet, just a few short years ago, the debate over disc brakes still raged on. The headlines in 2006 made note when a rider was riding with disc brakes, and inevitably, when riders blamed cuts and gashes on the fast-spinning rotors.

Notably, Pogačar was among the last holdouts in the pro peloton, still using rim brakes long after most other teams had transitioned to discs. Ineos Grenadiers also resisted the change well after other teams succumbed to the inevitable. That provides us with a prominent benchmark against which to measure the dying breaths of the rim brake.

In the 10 years since the UCI allowed a trial period of disc brake use in the pro peloton, these powerful stoppers have become standard equipment. Yet the path to this moment was a rocky one. And the eventual acceptance of disc brakes paved the way for other technologies that were initially met with resistance.

So, to mark a decade since they broke onto the road scene, Cyclingnews asked me to delve deep into the story of how we got here, speaking to riders, mechanics, and product managers who witnessed the shift in real time, and how disc brakes have affected racing since their arrival among the pro ranks.

Carbon Wheels Roll Into a Problem

In the lead-up to the UCI's decision to allow a trial period for disc brakes in the pro peloton, another innovation was causing celebration and headaches. Carbon rims offered weight savings and stiffness benefits. They also presented a new difficulty: how to counteract braking forces on the rim itself and the delamination caused by heat from brake pad contact at high speeds. No one was specifically asking for disc brakes. But almost everyone was looking for a solution.

"Everyone was looking for lighter, more aero rims, but that meant you had to get into carbon," says Dave Lawrence, Road and Gravel Product Manager for Shimano. "That complicated braking surfaces and brake pad compounds. Hearing stories about rainy stages at the Tour, brand new brake pads weren't making it through the stage. So people started thinking about how to make rim brakes more durable, but then you get into noise and vibration. And from the product side, you think, disc brakes will solve that."

Keep in mind this was all happening while tubular tyres were the peloton standard. As brake pads heated the brake track on carbon rims, the tubular glue could soften, which could increase the likelihood of a tyre separating from the rim. It was a sea of potential benefits littered with icebergs of problems.

Carbon wheel manufacturers spent lots of engineering capital to explore potential solutions, from different types of carbon to less brittle and more heat-resistant resins. While progress was quick by engineering standards, the peloton needed faster solutions.

"Frame design, materials, capabilities, wheel technology, and expanding market and ride style evolved exponentially 10 to 15 years ago," says SRAM Road Product Manager Dan Stefiuk. "Yet braking was still archaic and relying – better yet, hoping – that if you squeeze a piece of rubber or cork against aluminium or carbon, it would slow you down predictably."

Behind the scenes, both SRAM and Shimano knew the solution already existed, and had proven itself for years in the cycling world already. "It was across all of the mountain bike world," says Lawrence. "People would come in from other cycling disciplines and say, why don't you use disc brakes here? Gravel was just getting started, and that was the heyday of cyclocross, too. A few renegade brands put disc brakes on their bikes early on, and there was a lot of conversation around that. That's how a lot of trends happen: it wasn't one big moment, but instead a lot of little things that started to build momentum."

Knives, Machetes, Spinning Blades of Death

But momentum can crash hard if the end user isn't on board. The dichotomy of cycling has always been the path brands must navigate to satisfy both hobbyists and pros. While everyday cyclists were quicker to note the advantages of disc brakes, the pro peloton was more skittish about adoption. It didn't take long after the UCI allowed disc brakes in the peloton for the first controversy to arrive.

During Paris-Roubaix in 2016, Fran Ventoso got caught up in a crash and wound up with a deep gash on his leg. He contended that he made contact with a disc brake while still upright and attempting to avoid going down. While it's still unclear all these years later what did or did not cause the gash, Ventoso's reaction stole the headlines.

"Disc brakes should have NEVER arrived into the peloton, not at least as we know them right now," Ventoso wrote in an open letter after the incident. "I haven't met any rider who has run out of braking power with traditional brakes; I haven't known anyone who didn't see his wheels skidding when you brake with all [the] power you've got, no matter traditional or disc brakes. Then: why use them?"

Ventoso's worries were, of course, warranted. No rider wants to be put in any more danger than our inherently dangerous sport already presents. The incident did encourage manufacturers to consider ways to ensure disc brakes and rotors were completely safe to use at high speeds. Ventoso's language was perhaps more flippant than necessary – he calls disc brakes giant knives and machetes later in his letter – but it revealed deep hesitancy among the pro ranks who felt new tech was being foisted upon them without buy-in or rationale. Ventoso's crash led to the UCI suspending its disc brake trial period.

Controversy struck once more in the following year at the 2017 Abu Dhabi Tour. Team Sky's Owain Doull got caught up in a crash with just a kilometre left in the race, and in amongst the wreckage, Doull said he made contact with Marcel Kittel's disc brake. Kittel was the only rider in the race using disc brakes. Like Ventoso, Doull called for disc brakes to be banned or otherwise modified for rider safety. Though Doull's call for rider safety was, once again, very much warranted, video later cast serious doubt on the notion that Doull's injury was caused by a disc brake.

The 'Mixed Brake' Era

It was perhaps the 'not knowing' part that kept the peloton's heels dug in on the matter. Safety is rightly top of mind for both riders and organisers, and adding a technology to the mix that had such huge potential to affect race speeds, braking distances, and even the chaos of crashes was enough to make all parties skittish.

"From inside the peloton, I think there was a bit of scepticism at first along with a worry about safety," says Ruth Edwards (nee Winder), Olympian and staple in the women's peloton during the disc brake era. "People didn't know if you could literally get hurt from the rotor in a crash, and also the difference in braking speeds that could cause crashes."

American cyclist Peter Stetina agrees with his compatriot's view. "There were suddenly two braking speeds in the peloton between teams whose bike sponsors pushed discs or rim brakes.

"That became the blame for some crashes in that first 'mixed brake' season. I remember one crash where a rider had a deep laceration, and everyone blamed the 'hot burning knife blades on our wheels', which were not fit for the mass pile-ups."

Indeed, disc brakes not only changed a rider's ability to stop more effectively, but also the way the peloton moved. Some riders on rim brakes might need more distance to slow down to the same pace as a rider on disc brakes. And riders on the new technology could brake much later before a corner, leading to a change in race dynamics.

From a production side, bike brands had to adapt to new braking forces, new production cycles, and even entirely new frame designs. "Some manufacturers had spent a lot of time developing calliper-based frames," explains Lawrence, "and depending on where you were with your product cycle, if you just came out with a rim brake frame, you may not have had the time or money to make a disc brake frame in that timeline."

Complicating matters further were the many variations in calliper attachment points. Changing those points often meant redesigning a frame and fork entirely, not only to accommodate which calliper the frame could accept, but also the braking forces that came along with it. "Some frames were flat vs post mount, QR vs Thru Axle, 130 vs 142, which all made for inconsistencies," adds Stefiuk.

"Ergonomics were new, and levers were larger than today. But there is no question that disc brakes performed better, more consistently, and were safer than rim brakes, and that benefited experienced pro-riders and brand-new cyclists alike."

And those spinning blades of death? Stefiuk says the industry took a proactive approach to the problem after the early days of disc brake trials in racing and began to mitigate the risk of laceration by rounding the rotor edges.

Stetina recalls another unique disc brake problem: rotor rubbing. In the early days of road disc brakes, the distance between the brake pads and the rotors could vary depending on a lot of factors, including rotor warpage, disc brake fluid heating, poor calliper adjustment, and a myriad of other reasons. It was an audible reminder to riders that this controversial tech didn't feel quite polished to them.

It wasn't just driving the riders crazy. Manufacturers knew they needed to solve niggling problems like these to encourage widespread acceptance. "There was more pad rub than you would have liked in first generations," says Lawrence. "We learned a lot, and we improved the product. We have about 10% more pad clearance compared to the early generations. Our early rotors had more deformation under heavy braking, so you'd get that ticking noise on long descents. And that's gone now."

Frames themselves evolved too. While changes like wider axle widths were downright necessary, a lot of the compromises and design changes manufacturers made to accommodate the braking forces of disc brakes turned out to be a bit of overkill. "At the time, most carbon frame production had transitioned to Taiwan, and frame designers needed to learn how to accommodate disc brakes," Stefiuk says. "To be transparent, some early disc frames relaxed their geometry too much to account for 142mm over-locknut-dimension (OLD), and one way to do so was to make the chainstays noticeably longer. In the mind of an athlete, not only are you giving me disc brakes and a heavier frame, but now I have a frame that does not feel as responsive and doesn't allow me to race the way I want."

Ride any road bike today, and you'll find that responsiveness is back in spades. The learning curve didn't just apply to riders, in other words. Manufacturers found ways to leave most compromises behind.

Unsung Heroes Rolling Their Eyes At Night

It wasn't just riders who bristled against this new tech. Behind every pro rider is a pro mechanic staying up late at night to clean, adjust, repair, and prepare bikes for the next day of racing. Disc brakes presented not only a shift in the way riders attacked races, but also the processes mechanics had to now adjust to keep bikes safe and running perfectly.

"Just like veteran riders, there were mechanics who preceded Indurain at the time that disc brakes were being introduced," says Stefiuk. "Some mechanics welcomed the new technology and saw the benefit of hydraulics and not having to swap cables overnight as they became contaminated from the stage before, while some mechanics still smoked cigarettes with a can of diesel fuel and a paintbrush to clean the drivetrain."

Guys who cut their teeth wrenching bikes when Merckx was a young buck were now being told to adjust – very often in real-time – to tech they were being told could also be dangerous for their riders if they screwed it up.

Lawrence remembers the initial training sessions for those mechanics. "It's funny, depending on the teams, for the older, more traditional mechanics it was one thing after another," says Lawrence. "Electronic shifting, then disc brakes. You had to go in and teach these traditional mechanics how to bleed brakes. I was there in the early days. You talk to the technical directors who are on the cutting edge, and they were the ones who were like, 'oh god, here we go, I have to explain this to my five Belgian mechanics!'"

Both Stefiuk and Lawrence agree that mechanics are the unsung heroes of the peloton, and while they may have met disc brakes with gruff and grumbles, they also met the moment. In the long run, it becomes old hat, and a benefit for those wrenches up late at night preparing for the next day's stage.

Forgetting It Was Ever Controversial

Perhaps it was just succumbing to the inevitable, or maybe it was real improvement and real results that got everyone on board. Either way, disc brakes rule the peloton and rim brakes are now a chapter in cycling history.

"Acceptance from my point of view was just mandatory," says Edwards. "It's what the new bikes at camp had on them. Off you went to go training, and you got used to it. Disc brakes are great. I have a lot of confidence in my stopping power now – not that I remember not having that confidence before. But I wouldn't want to be on rim brakes in a peloton of disc-equipped bikes. Descending definitely feels different; it's just all about learning your speed and what your equipment can do."

From a logistical standpoint, there's no doubt significant improvements in bike changes and setup made a huge impact. Stetina notes that "tech got better, thru-axle design improved, rubbing rotors became less frequent, and it all happened relatively quickly. But in many riders' minds, it wasn't ever fully adopted until a big mountain finish was won on a disc brake bike. After that, there was no valid excuse for the riders anymore. I want to say it was Pogi or [Egan] Bernal winning a five-star stage somewhere, and then we were all like, 'okay, it's here to stay now.'"

Maybe that was all it ever really took: a stunning showcase of superior performance. Feats of man carrying feats of engineering. Isn't that so often how it goes?