Saturday, 2 August 2014

Hydraulic braking — the future for bikes?

Mountain bikers have known it for years: cable operated brakes are OK, but when it comes to power and feel, hydraulic brakes are way ahead. So why — up until now — have hydraulic brakes rarely been seen on road bikes?

By far the biggest factor that leads popular fashion in road cycling is the kit choice made by pro riders, and until recently hydraulic brakes have been too heavy for their needs. Rather than requiring just levers, cables and calipers, hydraulic systems need bigger lever housings with brake fluid reservoirs and master cylinders, hoses full of fluid, and calipers with slave cylinders. However, now that top-end race bikes are happily able to reach weights that undercut UCI regulation minimums, there’s a bit of spare mass to play with.

Meanwhile, the current on-trend desire for marginal gains means that riders want to maximise their potential on the way down a hill, as well as up. That all means that hydraulic brake systems are finally suitable for elite road cyclists — and therefore, the rest of us, too.

So what are those gains? The great advantages of hydraulic disc brakes are consistency in any weather — they don’t slip on the rim — and modulation. Modulation is supremely important and it refers to a brake’s ability to accurately reflect and inform a rider about how much stopping power they are exerting. Ultimately, good modulation allows the rider to do anything from scrubbing off a little speed, to achieving the zenith of the brake’s stopping ability without locking the wheels up.

That ability to avoid locking up wheels is particularly relevant to road bikes, where the small contact patch between thin tyre and smooth road may be much more prone to losing traction than a fat, knobbly off-road tyre. In practice, the current range of hydraulic brakes are so good, and so well-modulated, that wheel lock-up should be easily avoided.


The options

Of course, because hydraulic systems are such a part of mountain biking, people expect hydraulic to also mean disc brakes. However, last year American component brand SRAM launched two new road hydraulic brake systems. One was called ‘HRD’, and as expected featured discs. The other — called ‘HRR’ — working on the rim in much the same way as a conventional caliper brake, but offering the same level of modulation as hydraulic disc brakes, and far more effective power than cable-operated calipers. It was a new development for mass-produced road bikes, although firms such as Magura have been making specialist hydraulic rims brakes for some time.

Initially both SRAM’s hydraulic rim and disc brakes were only available with its top-level Red 22 groupset. However, for 2015 the hydraulic options have been expanded to form what SRAM is calling it’s ‘HydroR range’ of four complete hydraulic braking road bike groupsets — Red, Force, Force CX1 and Rival. The Force CX1 groupset only offers hydraulic discs, but the other three groupsets will provide a choice of disc or hydraulic rim brakes.
For existing SRAM users looking for an aftermarket option, there’s also the standalone S-700 HRR hydraulic rim or disc brake system, which is compatible with SRAM’s 10-speed mechanical groupsets. At a RRP cost of either £302 per wheel for hydraulic rims brakes, or £356 per wheel for hydraulic discs including the rotor, it’s not particularly cheap, but it does offer all the benefits of disc brakes without having to go to the even greater expense of buying a whole new groupset.
Not to be outdone, earlier this year Shimano also released a disc brake option that would allow owners of existing Shimano mechanical groupsets to upgrade to hydraulic brakes. Shimano already has the R785 range of hydraulic disc brake that works with its electronic shifting ranges, but the new RS685 hydraulic disc brake system due out this month is compatible with any of Shimano’s 11-speed mechanical groupsets.
As an aftermarket product it will cost RRP £469.99 — which includes a pair of shifters, fully bled hoses and calipers, but doesn’t include disc brake rotors or adaptors. However on new complete-build bikes it’s expected the cost will be roughly equivalent to going up a level in a groupset. And industry insiders expect it to be pretty widely adopted on new bikes, too.
So is hydraulic braking the future for road bikes? Not at all, it’s here already. When will you go hydro?