If you want to making the switch to disc brakes, one important thing to keep in mind is that you can’t just buy a disc groupset and fit it to any frame.
Unless the frame has been built with the requisite mounts, you won’t be able to use disc brakes. And even if you managed to bodge it through some welding wizardy, the different forces involved could compromise the integrity of the frame (although this applies much more to carbon than, say, steel).
In fact, the forces are so powerful that, theoretically, a wheel could be ripped out of the dropouts if the fork isn’t strong enough. The braking force on a disc brake bike is applied to the brake rotor, and that rotor sits on one side of the wheel hub, so unlike rim brakes, where there’s an equal force on either side of the wheel, and that force (if the calipers are correctly aligned) effectively works with the wheel to maintain its upright position, disc brakes unequally load the wheel.
That single-sided braking with discs means the frameset needs to be redesigned to account for these different torsional loads, which is why, when a manufacturer launches a new disc-specific frame, you’ll hear of a ‘revised carbon fibre layup’ on the fork and chainstays to strengthen those two key areas accordingly.
Outside of those structural considerations, there are two main visual differences on a disc-ready frameset: the forks and chainstays need to have a mount for the calipers, usually on the left-hand arm of the fork. That puts both brakes on the same side, as the rear has to be mounted on the non-driveside because of the cassette.
If, a few years ago, you wanted to ride disc brakes on the road, it would have been a bit of a search in order to find something and you most likely wouldn’t have been able to get one from a premium brand. But now almost all major manufacturers have at least one disc equipped model in their range and there will only be more in the future. We expect all brands who supply pro teams to have at least a prototype by the end of the season, seeing as the UCI has legalised the use of discs in the pro peloton during an initial test in August and September, before a full test throughout next season.
On a similar note, expect more brands to release disc models of their race bikes, because that’ll be what the pro teams want to ride 90 percent of the time except when the cobbled Classics come around again. Until now, disc brakes have mostly appeared on endurance/sportive bikes. For one, there hasn’t been a huge appetite for discs on racing bikes, because you haven’t been able to race on them, and two, the real-world benefits of disc brakes (the improved modulation and all-weather braking that we mentioned earlier) can be pretty appealing to ‘normal’ riders who are in search of a more practical – and comfortable – machine.
But a few manufacturers are ahead of the curve already and offer more than just their endurance bikes if you’re after something with discs. Specialized, for example, have adopted the idea early and already have disc-equipped versions of the Venge and Tarmac, and Colnago offer the C60 Disc.