Bicycle Brakes – Disc versus Vee on road bikes?11 May 2019
Where the argument has long gone quiet on disc versus vee brakes on mountain bikes, the discussion is just heating up on road bikes. Unlike mountain biking, this one won’t likely go quietly.
In a nutshell, professional cyclists on the grand tours won’t be riding bikes with disc brakes for at least two years – and even so this isn’t 100% feasible. Touring riders and commuters may be quicker on the uptake though there are drawbacks.
What’s so good about discs?
Some people have been saying that discs are being sold hard to make people buy new bikes. This isn’t entirely true. Discs are better at slowing a descent, and over a long distance don’t wear out your bike rims.
For the tourer, as with the mountain biker, you won’t necessarily want to go down a hill at 70mph, meaning you do want to use your brakes to control your speed. However if you’re going for the Yellow Jersey on the Tour de France you only brake for corners and are interested in braking occasionally, not for 5 or 6 miles continuously.
In the wet, disc brakes are better than vee brakes as the water won’t impact their operation. This is a good pro for the pros as on a nasty descent in the wet they need to corner more slowly to avoid going head over heels into a ravine. For the British cycling commuter, this is a real selling point – it is a great safety mechanism and likely to result in fewer bike accidents.
Disc brakes are far more efficient at stopping too. In the peloton you’re less likely to join a pileup in front of you, so arguably this could improve safety.
The first thing putting off the UCI international cycling competition union, is safety. In a peloton pileup there will be nasty injuries as hot rotors slice people up. It is bad enough when a Tour favourite breaks a bone as happened in the Tour de France with Bradley Wiggins in 2011. What happens if someone gets their femoral artery slashed?
Heat dissipation is another issue. Rims are large and dissipate heat better. Discs are smaller and the entire braking surface will heat up more quickly than the rims. Hot brakes are less efficient, and this will impact the stopping distance. The current technological direction of travel is toward the 160mm rotor, though again this makes a bigger leg slicer in a crash.
Weight is a problem too. The components of a disc brake system are heavier than on a vee brake system. Not only that, with the improved braking ability you need bigger forks to cope with the torsion that comes from a much more immediate braking effect. Bigger forks and heavier components? For the professional the conundrum will be whether to carry more weight up the hill, with the climb being the best way to win the race, or better stopping power on the descent – the descent being where you hold your lead not create it.
Under UCI rules, once approved a new technological advance takes a year before it is used in anger. Also under the UCI rules, no rule changes can take place in an Olympic season. If something was approved at the end of this season we’d be in the next Olympic year. Therefore, you won’t see the change until 2017 at the earliest. Nothing is on the horizon this year so far, so 2017 could easily become 2018…
Technology never rests
The great thing about technology is that it is about solving problems. Be under no doubt that there will be a disc braking system that is light and efficient enough to be used by the pros soon. How they’ll get around the safety issue is not something easily fixed, but the competitive advantage will win at some point.
Traditionally though an almost insignificant market in itself, the professional cycling market leads the mass market, so if the disc brake manufacturers crack the pro market then they’ve won over everyone. For now though, if you’re cycling 10 miles to work every day in all weathers, or perhaps considering doing a decent touring ride in the Alps then start thinking of disc brakes on your next bike. This could mean that the masses lead the elite – not the other way round for a change.