• Roberto Ferrari on the Flanders cobbles with disc brakes (Yuzuru Sunada)Source: Yuzuru Sunada
A year ago, just after the UCI had approved the use of disc brakes for road cycling competition as part of a ‘trial’, RIDE published this feature by Jack Lynch in issue #68 summarising the arrival of the technology in the pro peloton. This trial has now been put on hold, so we thought we’d re-publish the story online to offer some background to what is a fascinating and polarising discussion…
Jack Lynch

15 Apr 2016 - 9:25 AM 

There’s a braking revolution taking place: the industry has been insisting on it for years. Recently the UCI recognised the change  and stated that teams could trial disc brake use in WorldTour  road races this August and September. Is this a good thing for cycling or just the manufacturers who have more to sell?

The future of stopping: disc brakes on road bikes

“Teams will have the opportunity to use bikes with disc brakes at two events of their choice during August and September.” The UCI may have changed the way cycling is raced and bikes are built forever with just that one sentence. There was little doubt that we would eventually see discs in the professional peloton but notice has now been given: there is a concrete period when they will be trialled. Is this the watershed moment which will be looked back on and lauded as a worthwhile innovation? Or does it close the book on years of tradition in a sport obsessed with the idea of athletic romanticism?

The cycling world has never debated the purpose of innovation quite like it is now. Technological advancements have steadily rolled in, essentially since the inception of the bike, but have always been trialled for racing suitability, durability and improvement; not thrust into the scene for the sake of change. Let’s consider a few of the major improvements seen in the past three decades…

Since Look adapted ski binding in 1984 to create clipless pedals, the industry has neither looked back nor altered the original premise. It is a contemporary example where the desired function and design was achieved on the first try and only relatively minor refinements to weight and bearing systems have been noticeably changed over the years.

Shifting innovation hit hard in 1989 when we saw the introduction of Shimano Total Integration (STI) levers ridden for the first time in the pro peloton, namely by two original product testers, Phil Anderson and Jesper Skibby of the TVM squad. It would become mainstream but for a few seasons it was almost considered to be exotic! Campagnolo subsequently released its eight-speed Ergopower levers in 1992 which meant every rider using products from the two major manufacturers was able to shift gears without moving their hands to the down tube. This is the most practical upgrade in recent cycling history as it increased safety and riding efficiency for everyone. Some say that shift/brake lever integration is what lured many recreational riders back onto road bikes from flat-barred machines.

Nobody doubted carbon-fibre’s positive impact on road cycling since carbon frames first came to prominence in the mid-1980s. Countless trials spanning three decades were undertaken to ensure carbon was durable and safe for professional and recreational cycling alike. Aluminium frames were still seen in the pro peloton in 2005 which is hard to believe when, 10 years on, carbon frames are considered flawless and are now standard in the road scene. Despite over 20 years of ‘early’ testing which to a certain extent remains ongoing, few question the reason for carbon bikes and the ‘exotic’ frames continue to draw adoration for their low weight and high strength.

Electronic groupsets were quickly adopted by the majority of Shimano riders when 7970 was launched in 2008 and the current Dura-Ace 9070 is by far the most popular groupset in the WorldTour. After extensive testing Campagnolo appeased its aficionados with the release of the exquisite Electronic Power Shift (EPS) groupset in 2012. And SRAM? Well, it has got something big in the pipeline (don’t tell anyone, but we think it’s wireless shifting…). It is worth noting that Mavic can be credited with releasing an electronic groupset in 1992 called the ZMS (Zap Mavic System) which was tested by the ONCE and RMO teams at that year’s Tour de France. Ahead of its time, Mavic also unveiled a wireless electronic groupset in 1999 called ‘Mektronic’. It was heavy and unreliable, especially when confronted with heavy radio signal traffic so was widely shunned after much initial fanfare.

The point is, cyclists and the industry as a whole push technology’s boundaries and are early adopters of anything which is perceived to improve performance and experience. Many people say that road cycling technology has reached its ceiling – we will never see frames balancing weight, stiffness, aerodynamics and comfort better than what is on the market right now. Groupsets function perfectly and accessories are flawlessly tuned to a range of cycling physiques. Is this true? Is cycling soon to become less about what gear is used and more about how well we can actually ride the bike? Or is there simply going to be something completely new to wrap our heads around?

Disc brakes are certainly not ‘new’ but their application on road bikes is still in its infancy. Mountain bikers have been stopping with hydraulic discs on a mass level since the mid-1990s. It is now difficult to imagine hitting the dirt without tiny calipers and shiny rotors and using a V-brake or cantilevers is simply dangerous!

It took a long time for manufacturers to get it right with disc brakes though. There were years of failed pistons, leaky seals, fading performance, and squeaky pads until faith became widespread in the off-road community.

With road cycling, it is not the ‘faith’ that is the problem – it is the stigma. Many believe that there is nothing wrong with a standard cable and caliper set-up and that discs merely fix a fanciful problem. Such suspicions breed distrust in the technology and some riders write it off as the industry looking for ways to sell more bikes.

These feelings appear valid at this early stage but it will only be after several years that we will be able to look back and truly decide whether disc brakes are an upgrade or a detraction from the cutting-edge modern road bicycle raced in 2015’s WorldTour. Change is inevitable in a sport where speed is the main pursuit and stopping is something of an afterthought. Braking is now in the forefront of the mind and it seems as though it will take a long time for the cycling cohort to get on board.

Why is the disc discussion being raised?

On 14 April 2015 the UCI issued a press release stating that the use of disc brakes was permitted to be trialled in race conditions at the highest level of road cycling, the WorldTour: “Following numerous consultations with different stakeholders, tests will begin this season with a view to introducing disc brakes to professional road cycling.”

Following on from this, discs will be permitted to be trialled at any race throughout the 2016 season. Then, “if the experience is satisfactory, disc brakes will be officially introduced to the UCI WorldTour in 2017.” It is unclear whether they will be mandatory in the 2017 season but, like anything, it is expected that they will be universally adopted if the riders feel they deserve such treatment.

Why has the UCI decided to trial disc brakes?

After a couple of years speculating, it has come as a bit of a shock that the UCI would allow testing within four months of agreeing to a trial period. Clearly, it is an industry push rather than a rider request. The April release was duly signed off by the UCI and the World Federation of the Sporting Goods Industry (WFSGI) which is an organisation dealing in industry business prospects for Olympic sports. Essentially, the WFSGI can strong-arm individual sporting bodies into adapting rules or technology for the good of the sport’s commercial gain. (Shimano is a ‘bronze sustaining member’ of the WFSGI.)

Disc brakes on racing bikes means a virtual reset in the road market. No current high-end race-legal frames are able to fit discs – consumers will have to throw their bikes away and buy new ones. Apparently it’s a win-win. New, better bikes for riders; more money to the manufacturers…

WFSGI Secretary General Robert de Kock said that the “decision will further develop innovation and create new possibilities for the bicycle industry as well as additional performance for the riders.” Industry first, riders second.

This is not saying that the decision from the UCI was merely a cash grab for the industry, but it must clearly be seen as the driving force.

What are the positives?

There is no greater drawcard than the notion of almost identical braking in all weather conditions. Everyone knows the feeling of grabbing a handful of brake with no slowing effect – it is a sensation which would be gleefully forgotten. Team Sky’s head mechanic, Gary Blem, thinks that this fact will improve rider safety. “If you see some of the hairy descents that these guys are doing, especially in the Tour and the Giro, it would make sense to use a disc brake,” he told RIDE at the 2015 Tour Down Under.

Further benefits to riding disc brakes on the road is that they offer greater modulation at the lever. ‘Modulation’ is a word which is often used and sometimes misunderstood. It refers to the amount you can pull in the brake lever relative to the caliper biting on the brake surface. Disc brakes allow more ‘feathering’ because they do not grip like rubber on alloy and therefore do not lock up like traditional road calipers. This is especially useful on unknown descents or in the wet because caution can be exercised without compromising speed or the bike’s handling too much.

From a technical perspective, disc brakes are worthwhile on road bikes because the brake pads generally last longer, rims can be wider and lighter, and hydraulic units require little servicing. The final point could be taken either way as adjustments are a little more challenging than cable and caliper brakes but once set, only a major failure or accident necessitates qualified help.

Looking forward, tubeless rims will be easier to make and there will be more frame clearance for wider tyres. These factors have already improved tech performance for cyclocross riders who have ditched their cantilever brakes for discs, and may entice some road cyclists.

Considering the conditions of many cyclocross contests, it’s odd how few cyclocross racers have adopted disc brakes. Traditional cantilever-style brakes were always the product of choice as there is clearance for mud and gunk, but they offer poor stopping power and yet many riders still insist on using the old option rather than new technology.

What are the drawbacks of disc braking?

The first negative from a racing perspective is how to deal with neutral spares. Ideally, there would be a universal rotor size and hub spacing so wheels can be swapped easily. Once an accepted standard has been agreed upon, this argument will be silenced. Even now, a representative from SRAM believes that 160mm rotors are the most reliable, whereas Shimano’s opinion is that 140mm is fine for road racing. Both brands seem to think that thru-axles will be adopted by most frame and wheel manufacturers by the time disc brakes are deemed ‘race legal’.

Thru-axles are preferential to standard 5mm quick-release skewers as they are stiffer and safer. Strength is paramount when using disc brakes because there are only a couple of millimetres between rotor and brake pad. This means that any sort of flex in the forks, hub or rotor will make the pads rub and decrease performance. There is also the potential issue of the thru-axle set-up slowing down wheel changes but since the UCI made fork safety tabs (‘lawyer tabs’) mandatory in 2012, thru-axles should not cause dramatic delay.

From a more theoretical perspective, some have questioned the effects disc brakes will have on aerodynamics. One would think that the large rotor and bulky caliper will add some extra turbulence to the bike but this may be negated by the removal of the traditional rim caliper.

Aerodynamicists from Monash University have not investigated the effect of brake modifications to road bikes in the wind tunnel yet but offered a professional opinion based on the work done in the cycling space. Nathan Barry believes that the disc itself will only have a small effect but, “the caliper is bulky and typically not a smooth profile so it is likely to disrupt the flow over the fork and stays.” He said that the rear caliper should not be such an issue because the air is already turbulent in that region. However, the front brake, “has the potential to increase drag – though it will be a small effect.” If and when discs become UCI sanctioned, frames will start to be designed around the caliper to ensure that airflow disruption is kept to a minimum.

Other drawbacks regarding disc brakes relate to how riders will evolve to their equipment. Getting used to how heavy to apply hydraulic brakes should be resolved quickly for most people but some may take longer to adjust to the nuance. Unfortunately, nothing can be done to heighten a person’s braking proprioception except practice.

Servicing is more difficult – there is little question about that – but it is far from impossible and, if anything, discs will be a little bit more reliable because they either work or they don’t. Unlike standard calipers, there is no left/right pad set-up or the potential to break or pull through a wire cable. A disc brake operates well when there is no brake pad rub and they pull the bike up quickly – there is no ambiguity.

One real problem to face riders, (and mechanics) is the potential for disc brakes to squeal. Unlike mountain biking, there are many times on a recreational ride where road cyclists are forced to gradually slow down. Stopping at a traffic light is a repeatable example where brakes are applied lightly as the rider rolls gently to a stop. This technique could glaze the pads and cause squealing at low speeds which can really irritate.

The most common reason for brakes squealing is poor maintenance. Seemingly innocent applications of sprays or other contaminants can leave pads and rotors infected and howling on the road (often irreversibly). Any experienced shop mechanic can regale someone with stories of customers bemused by their noisy MTB brakes after ‘cleaning’ them with WD-40, Mr Sheen or similar products.

Road cycling’s propensity for low-speed braking in conjunction with disc brakes’ relative sensitivity to contaminants makes the potential for spotting why brakes squeal a veritable minefield.

The hope is that, once popularity is confirmed, manufacturers will create brakes specifically designed for road bikes, not merely alterations to mountain bike ones. (SRAM Red calipers are the most striking on the market at the moment but Shimano has a new caliper which is markedly smaller than anything else it has produced.)

What do teams and manufacturers think?

When the announcement of a trial came from the UCI, we asked teams and manufacturers to offer some commentary on their expectations of disc brakes in the peloton. Beyond what Gary Blem from Team Sky already offered earlier in the year, there is a mix of reactions but the consensus seems to be let’s wait and see how it goes…

“Unfortunately, we’re unable to make any comments as a single team at this point,” wrote Daniel Sánchez from the Spanish Movistar team. “We remain ascribed to what the AIGCP (Association International des Groupes Cyclistes Professionels) has expressed about this matter.”

Astana’s Slovenian directeur sportif, Gorzard Stangelj expressed some resistance. “Until all the factories which supply brakes to the teams can agree on a universal system, the disc era will not begin. That will not be achieved by the middle of this season! My opinion? I am more for the traditional bike, no electronic gears or disc brakes.”

Meanwhile, one of the major component manufacturers that is yet to release any disc brake iteration offered a one sentence summary. “Campagnolo is dedicated to putting its riders in the best position for victory through cutting edge and advanced components and wheels that offer them a technological advantage.”

These responses are all fairly typical of Campagnolo-equipped teams and the Italian company itself. It seems as though they do not want to commit to the technology until it has been signed off by the UCI. Rather than lead the change, they prefer to watch and react to the decisions made by other teams, riders, and manufacturers.

Campagnolo has yet to reveal any disc brake plans and may need to tread water for a while if they become standard fare in a short timeframe. Interestingly, Campagnolo only has two representatives sitting across the bicycle committees for the WFSGI. Shimano and SRAM have eight between them, including Bernhard Johanni, chair of the ‘Technical Committee’, and Tim Gerrits, the chair of the ‘Wheel Committee’. Perhaps this is an awkward coincidence but it might give an indication as to Campagnolo’s interest in volunteering to help accelerate the industry’s evolution and explain the lack of comment from the teams.

In stark contrast to the Campagnolo sponsored teams, the Shimano-friendly BMC Racing forwarded its response to the head of communications at BMC Switzerland. It is sitting comfortably knowing that it has already successfully built a race-ready, disc-equipped bike – albeit an endurance model. Presumably, the technology should not be too difficult to transfer to the teammachine SLR01. (It’s also worth noting that BMC Switzerland also has representation on the cycling committees of the WFSGI.)

“Disc brakes are without a doubt the future of road cycling, and for recreational and non-race situations,” said Fiolo Foley, head of communications of BMC.

“There seems to be little holding back the industry and the final touches to the technology are setting in now. There’s no doubt that as disc technologies move ahead and standards come to take hold, there will be widespread acceptance, and BMC embraces the time when that happens. BMC Switzerland and the BMC Racing Team are constantly working towards developing the products the race team needs; when the time comes that the team is ready for the change, the product will be ready.”

Which frame manufacturers are ready?

Brands which already manufacture a racing frameset with disc brakes have an obvious advantage on their competition. Specialized’s Tarmac springs to mind, as does Colnago’s C59 disc which, upon its release in 2012, was one of the first hydraulic disc road bikes available. Colnago claims that its C60 and race-ready V1-r disc are going to be made commercially available shortly. Pinarello also offers its second-tiered Dogma 65.1 in a hydraulic disc frame.

Giant, BMC, Cannondale, Trek, Focus, Merida, Scott, Ridley, and a host of other companies are hot on the heels of the class leaders as they each have high-end road bikes fitted with disc brakes. The problem with all of these models is that they are all labelled as ‘endurance’ frames (or are aluminium only, in the case of Cannondale’s CAAD) and, whilst they are sometimes raced by professionals, the idea of riding tall head tubes and long wheelbases can be a bridge too far for some consumers.

The only sponsor of a WorldTour team which does not have a carbon disc brake-equipped road bike in its armoury is Canyon which supplies Movistar and Katusha. The German company has made one in the past, however, but it was more of a futuristic showpiece than a bike to be raced.

Will disc brakes be universally lauded…?

Early adopters need all of their preconceived concerns addressed before being convinced on new (or in this case, reimagined) technology. Once rotors are standardised and thru-axles implemented, disc systems must have the ability to adjust the pistons whilst riding or during a brief stop. SRAM is said to be working on some form of pad contact adjustment or quick-release much like an adjuster barrel on today’s road caliper. Shimano seems to be marketing its discs by highlighting the benefits of everyday use, rather than the problems which might be encountered when racing, and is not admitting to working on any ‘piston release’ technology. Road cyclists have a greater sensitivity to resistance than the obstacle-distracted knobbly-tyred dirt warriors and every small ping of rotor on pad could cause some riders to despair.

Every element must – and will be – refined to suit road bikes. The relatively bulky levers with the main oil reservoir need to be reduced in size, as does the caliper. Thru-axles need not be 15mm and 12mm thick (front and rear) as they are on mountain bikes and the locking lever should be made more aerodynamic. Road cyclists like things to be slim and light because removing bulk is aesthetically pleasing and is generally lighter, translating to a more efficient bike.

Frame manufacturers must make special provision for internal hydraulic hosing too. It is slightly thicker than an outer brake cable but does not hold the tension of a mechanical brake or gear outer. Cable slackness and internal frame routing translates into a loud rattle pretty easily and companies will need to avoid that on first attempt or else consumers may refrain from buying.

* * * * *

Whether you are a traditionalist or lover of modern innovation, there is no doubt that hydraulic disc brakes are making an expected, yet rapidly accelerated entry into the road bike scene. The UCI’s announcement in April may change the way bikes are raced into the future but there needs to be some serious discussions held before the consumer is subconsciously bullied into throwing their bikes in the bin and starting again.

There is no doubt that there are myriad benefits to disc brakes but for every positive, there seems to be an unknown. The disc brake debate is far from clear-cut and the cycling world will have its eyes fixed on the two races in August and September where teams and manufacturers choose to trial their wares. Gary Blem summed the situation up aptly: “When a new idea comes out, everybody is normally a bit afraid and a bit negative. As long as we stay open-minded, maybe it will revolutionise the sport in a way, you know? Or maybe not. We’ll have to see.”