Road Disc Brakes – Stop! The Insanity.
- by Christopher Jones
- Published: 3 July 2014
When the UCI ratified disc brakes for the 2010 / 2011 cyclocross season, it set the foundations for innovators to look further into road cycling. At the time SRAM product manager Paul Kantor asked, “why wouldn’t you see this evolve onto a pro tour bike?” Skip forward to 2014 and while you’ll spot disc equipped bikes in bike shops, competitive pro tour cycling is so entwined with everyday road cycling that it is as though the industry and cyclists alike are standing on the edge waiting for the UCI to yell “Jump!”
Talks between key industry groups and the UCI are in full swing, but there are open questions, some ridiculous and some well-grounded. Answers are needed and speculation is rampant with naysayers creating horror visions of red hot, sharp edged disc brakes causing carnage in pro and amateur cycling.
As a keen mountain biker, the transition from V-brakes to disc brakes was like night and day to me and it will be unthinkable to revert, but do disc brakes really offer road cyclists a significant benefit over traditional rim brakes? Lets ask the two main players, Shimano and SRAM. Troy Glennan from Shimano Australia and Rob Eva of SRAM Australia both tackled a series of question from Bicycles Network Australia to find out why disc brakes on road bikes are the future.
So what is the advantage of disc brakes? Rob Eva says “I think disc brakes have an advantage anytime you need to use your brakes. Great modulation, great power, and very consistent braking in all weather conditions.” Troy Glennan of Shimano had an almost identical answer, so it was time to find out whether there are situations in pro-cycling events where a traditional rim brake would be preferable, “With correct braking technique , longer mountain descents, the use of a disc brake will not only improve braking performance, but also handling performance.” Eva adds, “The weight of the bike could be a factor but nearly all mountain stages there would be some down hills and it could snow or be wet and I would take the better braking over a few grams.”
SRAM Rotor and Red 22 Hydraulic disc brake
A major criticism of disc brakes is that they create an aerodynamic disadvantage and there are different viewpoints offered. “I’m sure it does change the aerodynamic profile of the frontal surface area, as a majority of the additional mass is behind the wheel and the air already being broken by the wheel,” suggests Troy Glennan, “I don’t see this as a major disadvantage.” Far from being a detracting factor, Rob Eva of SRAM says “We see it as an aero advantage not a disadvantage. The caliper at the fork is a big wind catcher as opposed to a disc caliper sliding in behind the fork or the seat stay.”
Shimano Freeza Rotor and R785 Hydraulic brakes
Both Shimano and SRAM have overcome the limitations of creating hydraulic braking for the integrated brake and gear system which traditionally relies on the mechanical cable pull. There are different configurations available in different brands, such as mechanical pull disc brakes and hydraulic rim brakes. If hydraulic rim brake offer the same advantage of braking modulation as a disc brake, why would a road cyclist prefer a disc brake?
“They don’t have the same advantage as disc brakes and rims brakes on carbon rims are very inconsistent,” argues Rob Eva, “you need to take the wear factor in a rim into account as well. In the wet, a rim and pads can wear at an alarming rate. Also with a disc wheel, there are no restrictions with having to have a braking surface incorporated into the rim.”
This suggests that hydraulic disc brakes for road bikes are a winner, but with Shimano/SRAM and Campagnolo already influencing compatibility on race day, won’t this cause chaos on race day for pro-cyclists who suffer a mechanical?
Rob Eva, also an accomplished mountain biker who has lived through the evolution of mountain bikes, says: “We have the problems right now with thick and thin rims. We also have the 10 speed and 11 speed wheel problems, but no one talks about that. With disc, we will supply one size rotor and for 11 speed wheels only by this time. I see it as a plus not a negative.”
Troy Glennan also recognises how technology in the mountain bike world has changed: “Compatibility will definitely become a hurdle. 130 / 135 mm spacing debate, QR axle / E thru axle. Then is there is rim brake offering as well. It’s a massive logistical / compatibility hurdle.”
Bleeding hydraulic disc brakes is a learning curve, but is straight forward
Regulations and standard will play a keen role in the future of disc brakes for the road and the key brands need to collaborate as well as compete. Shimano and SRAM are well ahead, Campagnolo are working on disc brakes, while TRP jumped the mark with the Parabox and are in the market with the Spyre. What about Hayes or Hope who have carved a niche in mountain biking? Hope have already made a move with with the V-Twin brake which converts cable-pull STI levers for hydraulic braking, and with their expertise are well positioned to provide after market equipment for weight weenies.
But are the disc brake opponents misguided or is there some merit in their arguments against? “In my opinion there is still a massive safety issue of use in pro tour pelotons,” concedes Troy Glennan, “Some of the mass pile ups seen already can cause serious injuries, add into this rotors that, as seen in MTB crashes, can cause serious injuries from contact with a rotor.”
“Then there is the difference in braking power between rim and disc brakes, if riders have the option to use either or? A rider on disc brakes may be able to brake much later than one on rim brakes, and a following rider may be misguided to the braking point on a descent.”
The actual differences in braking power and the skill of the cyclists is a discussion that will likely continue, the fans and opponents alike will undoubtedly each have the “I told so so” moments.
Rob Eva paints a different picture and challenges the opponents: “With disc brake technology you need to ride it to really feel the difference. All these guys sitting behind keyboards commenting on websites and social media need to try these bikes and brakes out, then with an open mind they can make a consumer buying decision.” Rob continues: “Maybe you will not feel the benefits riding up Beach Road in Melbourne on a nice summers day, but up at Bright on a long downhill with miserable weather you could honestly not go back to rim brakes.”
Is the road bike world on the verge of the disc brake revolution?
While my own finish line aspirations on a bike are modest, confidence in braking is important and adds to the pleasure of cycling. Upgrading to disc brakes means a new bike with new groupset and new wheels…. new everything. I am conditioned from mountain biking and for many years have felt that disc brakes on road bikes is a logical progression. My next bike will be disc equipped.