My name is Elin - A pro cycling lover's reflections

Restart of disc brake trial

Category: Cycling

When it comes to hybrid and MTB bikes, it is hard to find a bike these days without disc brakes. Even so, it has not become as popular among road cyclists. The sport’s governing body, Union Cycliste Internationale (UCI) allowed pro teams to trial disc brakes in August and September 2015. Before that, disc brakes were illegal. 

In 2016, the trials continued. However, after the Paris-Roubaix, the disc brakes were suspended for safety reasons. Francisco Ventoso had a crash and was taken to a hospital with a deep gash to his leg. An injury that he claimed were the result of a disc brake. Ventoso himself wrote in a letter that disc brakes “are giant knives, machetes when crashing against or crashed by them at a certain speed. The UCI banned the use of disc brakes after that accident, which means the professional peloton was merely allowed to use them for four months. However, it seems unlikely that Ventoso's injury was really caused by a disc brake, as Direct Energie and Lampre-Merida, the only two teams using disc brakes in Paris-Roubaix, say none of their riders saw an incident with Ventoso. It seems more likely that it was caused by the cassette.

Now the UCI has allowed the disc brakes again. However, there will be a difference from last season, as the UCI sayd that all rotors must feature smoothed and chamfered edges reduce the risk of danger to the riders.

During the upcoming Tour Down Under most teams, if not all, will be using traditional rim brakes, but later in the season, the bike manufacturers will likely ask to see their riders on new disc brake frames. The brands are, after all, showcasing their flagship models through professional road racing, and they currently want to sell the disc brake bikes.

The positive things with disc brakes are that they generate much more stopping power, which means that you don't need to push the levers very hard to stop. They are also more consistent in varying weather conditions. Personally, I like the disc brakes on my mountain bike, and there is a big possibility that my next road bike has disc brakes.

For the pro cyclists though, there are some downsides. Like the fact that rim brakes are lighter. The components aren't too different weight-wise, but what makes it heavier is the disc-compatible wheels and frames. Furthermore the forks are generally heavier. Rim brake-equipped bikes are about 500g lighter than one with discs.

Another advantage is that there is an industry-wide standard for rim brake equipment. When some teams are using disc brakes, this is expected to cause significant headaches for neutral support, according to Butch Balzano, of SRAM NRS.

Disc brakes come in several different sizes; the main road sizes on the market are 140mm and 160mm. When it comes to the wheels, they are attached to the frame with either a classical quick-release skewer/drop-out or with a more rigid thru-axle. The problem with the thru-axle for the neutral support is that there exist two different sizes (12mm and 15mm). And to make it even worse for the neutral support, the rear cassettes from Shimano, SRAM and Campagnolo are different.

"It's extremely frustrating to run up to a rider and have the wrong wheel, but you can't run out of the car with six wheels in your hands," Balzano said to Cyclingnews.

However, he said, if you manage to grab the right wheel, the change times are pretty much the same.

"If it is a QR rear, it only takes me fractionally longer to change a rear disc wheel than a rear rim brake wheel because we've practised it so much," Balzano revealed. "So it isn't a big issue. If it's a TA, it's going to take a long time. We can still do wheel changes, but anyone with a disc it's going to take longer."

With the QR, you can open the lever and pop the wheel out of the frame, which takes less time than to unscrew the axle and remove it before removing the wheel out of the frame, then reverse with the new wheel. This means that it will go faster to change the entire bike if the team car has one on the roof.

Rim brake calipers are easy to adjust, also with the rider on the bike. With the disc brake, it will no longer be possible to fix a rubbing brake pad while hanging onto the team car.

"You can't do it on the fly on a disc brake - it's too low. There's one thing to grabbing a rim brake caliper - they're easily accessible from the car window, but the discs are about a foot off the road surface. There's no way you're getting down there. And the caliper is within an inch of the spinning spokes! You're not going to get your hand anywhere near that!"
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