After a faltering start, it's clear that disc brake race bikes now dominate bike manufacturers' ranges, even if the 2020 Tour de France was won on bikes with rim brakes. Here are the 2021 disc-braked race bikes that have got us most excited.
If you can control your speed better, you can go faster, which can make disc brakes a racing advantage
Separating braking from rim integrity means you can carry on riding with some forms of rim damage
The weight disadvantage comes down every year as manufacturers slim down disc calipers and mounts
Bike makers also claim they're solving any aerodynamic issues disc brakes pose
Why would you want disc brakes on a road race bike at all? The promised benefits are greater modulation and more power, especially in wet conditions, no fade on long descents, rims that don’t wear out, less maintenance and longer lasting brake pads.
On the other hand, disc brakes are currently heavier than rim brakes and there are some concerns about their impact on aerodynamics, although Giant, for example, claims that its Propel Disc has less drag than its rim brake predecessor.
Toward the end of June 2018, the UCI (cycle sport’s world governing body) announced that disc brakes would be allowed in road races, after a lengthy trial period that was marked by occasionally acrimonious debate about the safety of discs.
The UCI first introduced a trial period for using disc brake race bikes in the pro peloton at the end of the 2015 season, but suspended it following injuries to riders in the 2016 Paris-Roubaix that were alleged to have resulted from disc rotors.
Read our story from last year: Have disc brakes really led to injuries in peloton?
The trial was later resumed with slight modifications to disc rotors demanded, and riders such as sprinter Marcel Kittel competed on disc brake race bikes throughout the 2017 season.
Since then it's been open slather. Some teams have switched entirely to discs, some have stayed with rim brakes. Pro racing, though, is notoriously conservative: it took a while for indexed gearing and clipless pedals to completely take over the pro peloton even when regular riders were fully on board.
But almost all mid-to-high-end road race bikes now sport discs, and improving the weight, aerodynamics and ride feel of disc-braked bikes has been the main focus of every large bike maker's development effort for the last couple of years.
Orro's Venturi STC is an evolution of the brand's well-liked Venturi, now with an integrated bar and stem that routes all the cables directly into the frame. The 'STC' stands for spread-tow carbon, which Orro says allow a much larger number of fibres in a smaller space, reducing weight while maintaining stiffness and comfort.
Tester Stu loved the 2020 version of this bike, writing in his review: "Orro has quite simply nailed it with the Venturi Ultegra Di2 Wind 400. Comfort, speed, handling, feedback and stiffness – you can have it all. And the icing on the cake? It's a looker too!
"I've ridden a lot of bikes over the last 20 years, especially in the 10 that I've been with road.cc (41 in 2019 alone), and while a lot of them have been very good, there are probably ten or so that really stand out as brilliant – and the Venturi is one of those.
"I like a stiff bike. I want that feeling of performance, and if that sacrifices comfort, I can deal with it. I like a frame that feels alive, a bit on the edge, I want to feel everything that is going on from that tiny rubber footprint on the ground, and if I need to take a little bit of a battering to get that then so be it.
"The Venturi delivers that in spades, but the carbon lay-up used means it manages to do that while being very comfortable too, without taking anything away."
The Vitus Vitesse Evo Disc offers a helluva lot for your money. It’s a carbon fibre, disc brake-equipped road bike built around a race-focused geometry. Previous versions have offered superb performance and it seems a safe bet this latest incarnation will too. Vitus says the new Vitesse Evo is "lighter, stiffer, more aerodynamic and more comfortable" than the 2020 version. It boasts on-trend dropped seatstays, a new carbon lay-up and increased tyre clearances.
And it might be the cheapest bike you can buy with SRAM's 12-speed wireless Red eTap AXS shifting, though we're not claiming a bike that costs the thick end of five grand is cheap. It rolls on Reynolds AR29 DB Carbon wheels and Schwalbe ONE Performance tyres.
It was a bit like the moment in Mike Oldfield's first album where Vivian Stanshall breathes "Plus … tubular bells!" Canyon finally released a new version of the Aeroad in late 2020 after a period of anticipation so intense some Canyon fans resorted to stickering-up generic aero frames as the 'new' Aeroad.
It was worth the wait, according to road.cc technical editor Mat Brett who says "this aero road bike is an absolute belter whether you’re flat-out sprinting, haring down your favourite descent or tackling the steepest climb in your area, and you can’t say that about every bike of this kind."
The top model has Canyon's new Aeroad 065 frame, of course, plus a full Campagnolo Super Record EPS groupset and Campagnolo Bora One wheels, but that's not all. Canyon has introduced a width-adjustable handlebar for the top models of the new Aeroad that also allows the bar to fold for easier packing into a flight case. Clever stuff.
Specialized's stunning new Aethos is an apparent contradiction: it's a race bike that, in its lightest version, you can't actually race because it comes in under the UCI's minimum weight limit of 6.8kg. Of course that's nothing you can't fix with a few carefully deployed weights.
With a 588g frame (56cm version), Specialized says the S-Works Aethos is the most technologically advanced model it has ever made, with an aim of improving ride quality rather than weight — that it barely troubles the scales is apparently just a nice side effect.
The latest iteration of the Trek Émonda focuses on aerodynamics more than ever before, which makes this SL6 Pro one very quick and efficient road bike. The stiff frameset offers a firm yet fun ride, while the component choice keeps the weight down to exploit that stiffness on the climbs. It's a very good all-round package.
For 2021 the Emonda has morphed from being a platform focused solely on low weight to having some aerodynamic impvements in the mix too, the aim being to make the fastest bike up the legendary Tour de France climb of l'Alpe d'Huez.
The Emonda SL 6 Pro takes Trek's learnings from the high-zoot Émonda SLR and brings them to a more sensible price with a Shimano Ultegra groupset and Bontrager Aeolus Elite 35 carbon wheels.
Giant was one of the first bike makers out of the blocks with 2021 models, announcing the new version of the TCR Advanced in April 2020, getting us all excited about a bike with a claimed 140g weight reduction in the frame thanks to new materials, new layup and even a reduction in the weight of the paint. Tube shapes have been tweaked for improved aerodynamics too, Giant says, though the TCR remains the range's weight-focused platform and the Propel the true aero bike.
Road.cc technical editor Mat Brett is impressed by the results. "The Giant TCR Advanced SL 0 Disc's understated looks disguise a stunningly good performance," he says. "This lightweight bike is hugely responsive and handles precisely. Add in aero features and excellent components and it's a real winner."
Cervelo's new Caledonia platform straddles the divide between pure race bike and endurance bike — and there's a very good reason for that. This is a bike aimed squarely at racing, but one race in particular: Paris-Roubaix. The cobbles of Northern France make very different demands of a bike and rider from the slopes of the Alps or Pyrenees. Compared to bikes tailored for the mountains, Cervelo says the Caledonia has longer chainstays, a lower bottom bracket and increased trail, all changes that improve stability.
Cervélo puts the Caledonia into a category that it calls 'modern road', meaning that it's intended to tackle tarmac, broken surfaces, potholes and dirt roads.
There are actually two different platforms: Caledonia and Caledonia-5. They're both carbon fibre and disc brake-specific, and they share the same geometry and levels of stiffness but the Caledonia-5 is lighter and has completely internal cable/hose routing on models with electronic shifting, whereas the Caledonia's cables/hoses are external between the handlebar and the frame/fork.
The range starts with the Caledonia 105 at £2,700 and peaks at £9,699 with the Caledonia-5 Dura-Ace Di2.
Merida’s updated Reacto aero road bike is available in both disc brake and rim brake models.
Merida has slimmed down the Reacto’s tubes to improve aero efficiency, introduced a lower seatstay connection with the seat tube and added a one piece cockpit.
Merida also says that it has improved comfort through the redesigned seatstays and given its S-Flex seatpost a slimmer cross section and a bigger ‘window’ – the notch that’s cutaway to add more downward movement.
The disc brake Reactos come with cooler technology like Merida uses on its Sculturas. There’s a forged aluminium component between the brake and the frame/fork that’s designed to allow heat to dissipate through CNC-milled cooling fins. The idea is that this reduces the amount of heat that gets transferred to the carbon-fibre on long descents.
The CF4 version of the disc brake frame uses the RAT (Rapid Axle Technology) first introduced by Focus for quick wheel changes in race situations, while the CF2 version has threaded 12mm thru axles.
BMC claims a weight of just 820g for the latest version of the Teammachine's carbon fibre disc brake frame, but while that's actually 5g up on the previous model, the fork and seatpost have shed 50g and 10g respectively. A new version of the ICS integrated bar and stem also shaves weight and improves aerodynamics.
This latest Teammachine looks quite similar to previous models, but you wouldn't expect BMC to just abandon the distinctive visuals they've spent a decade tweaking. Nevertheless, BMC says every part of the new Teammachine SLR01 has been improved or refined, from tube shapes and bottom bracket junction to cabling — there are even integrated bottle cages to smooth the airflow.
Scott’s Foil Disc has a very similar frame to the existing rim brake model but the fork has been completely redesigned to manage the asymmetrical forces of disc brakes and to control the airflow around the front brake. Most notably, the lower sections of the fork come with aero tabs to smooth airflow over the calliper.
That fork comes with internal cable routing and enough clearance for 30mm wide tyres.
The Foil Disc uses 12mm thru axles front and rear. The front axle’s head is 25mm in diameter, the idea being that this larger than normal contact surface between the fork and axle is better able to handle the load coming from the front brake.
The CAAD13 is the latest in a long series of well-received aluminium bikes from Cannondale, with a more refined ride than the CAAD12 and available with or without disc brakes.
Ask most cyclists about aluminium and they’ll probably tell you it’s stiff, and if they’re being really unfair they’ll say it’s harsh. But advances made by companies still willing to invest in aluminium like Cannondale have produced aluminium bikes that are anything but, and instead offer genuinely smooth and compliant rides.
The new CAAD13 is on another level though. Our one criticism of the CAAD12 Disc was that the front-end felt too firm. There was too much feedback coming through the handlebars and it wasn’t matching the smoothness present at the back of the bike. Cannondale has remedied that criticism and in the CAAD13 produced a bike that is wonderfully smooth all-round.
As we expected, Bianchi unveiled a disc brake version of the Specialissima toward the end of 2020. Bianchi claims a frame weight of a feathery 750g, the same as the rim brake version, and aero improvements carried over from its Oltre aero road bikes, including internal cable routing, an integrated seat clamp, and tubing that’s shaped to reduce drag.
As well as the inevitable celeste blue and black the new Specialissima is available in a rather lovely greenish blue option that Bianchi describes as “greenish blue”. Straightforward, those Italians.
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John has been writing about bikes and cycling for over 30 years since discovering that people were mug enough to pay him for it rather than expecting him to do an honest day's work.
He was heavily involved in the mountain bike boom of the late 1980s as a racer, team manager and race promoter, and that led to writing for Mountain Biking UK magazine shortly after its inception. He got the gig by phoning up the editor and telling him the magazine was rubbish and he could do better. Rather than telling him to get lost, MBUK editor Tym Manley called John’s bluff and the rest is history.
Since then he has worked on MTB Pro magazine and was editor of Maximum Mountain Bike and Australian Mountain Bike magazines, before switching to the web in 2000 to work for CyclingNews.com. Along with road.cc founder Tony Farelly, John was on the launch team for BikeRadar.com and subsequently became editor in chief of Future Publishing’s group of cycling magazines and websites, including Cycling Plus, MBUK, What Mountain Bike and Procycling.
John has also written for Cyclist magazine, edited the BikeMagic website and was founding editor of TotalWomensCycling.com before handing over to someone far more representative of the site's main audience.
He joined road.cc in 2013. He lives in Cambridge where the lack of hills is more than made up for by the headwinds.