Magura have already had some success with their RT8TT braking system. The hydraulic time trial levers and rim brakes were fitted to Ryder Hesjedal's Cervelo P5 as he TTed to take the Giro's Maglia Rosa in Milan, and David Zabriskie took the ITT win using the system over in the Tour of California too. So far the hydraulic brakes have been TT only but we've just had our first hands-on look at the RT8C road system.
If you're familiar with the Hope V-Twin or the TRP Parabox then the Magura box does precisely the same thing, except for rim brakes rather than discs. For the uninitiated it's a simple mechanincal to hydraulic interface. The cable from your road lever goes in at one end and that mechanical pull is converted to a hydraulic push via a linkage and a master cylinder. There's a hose running to the brake, and a piston between the callipers pushes up to apply braking force to the rim.
And what's the benefit of that? Well, Magura will have you believe that there are several. For starters, the hydraulic brakes offer increased power for a given force at the lever. Magura claim that the RT8TT is the most powerful rim brake on the market; we're not sure exactly how the converter will affect overall power but you can expect it to be more powerful than a standard rim brake.
Mat's ridden the TT version when he went to try out the new Cervelo P5, and he was impressed: "Those hydraulic brakes really do live up to the promises that Magura make," he says. "You often don't need all that power. And in damp conditions, it's relatively easy to skid on skinny road tyres so you don't want to leave braking until the very last moment. But the thing is, with all that power at your fingertips, you do get a whole load of confidence. Knowing that you can stop at a moment's notice does mean that you do lay off the levers that little bit longer. You see a corner coming up and you're not sure if you need to brake or not. With less power at your disposal, you have to brake to be on the safe side. With these, you can get closer to that corner before you have to make that decision, and by which time you might see that, actually, you don't need to slow down after all... and that's money in the bank."
The other major advantage of the hydraulic system is that it's unaffected by odd cable routing. That's more of an issue on a TT bike where you're feeding the brake run through the bars and frame, but with an internally-routed road frame there's no loss in performance from a more circuitous route.
Obviously it's a lot simpler to retrofit too; whereas discs require a different frame and fork design, the Magura brakes are the same single bolt fitting as a normal dual pivot calliper, meaning you can just swap them out and keep the rest of the transmission the same.
In the TT guise Magura claim that the system, at less than 500g including levers, is the lightest out there too. That won't be the case with the road brakes as you're adding the weight of the conversion box to the (admittedly very light) callipers. Even so, the all-in weight of 483g is pretty good.
Aero performance was a big factor with the RT8TT brakes, in fact it was the main driving force behind the design. The callipers are the same in this case so you'll be getting the same aero advantage there, but obviously that's offset by the fact that you're bolting a box under your stem. We didn't take it to a wind tunnel or anything, but our finger-in-the-air guess would be that the drag of the box would probably cancel out any advantage from the callipers. More than likely you'd switch for the improved braking performance rather than any aero advantage.
RRP for the RT8C system is likely to be in the region of £550; that's a big stick of cash but you can spend as much on lightweight Carbon callipers if you want to. Dura Ace callipers are around £200 and Super Record will set you back £260, for comparison. Release date is to be confirmed, but you can expect them to hit the shelves some time in late summer or autumn.
Dave is a founding father of road.cc, having previously worked on Cycling Plus and What Mountain Bike magazines back in the day. He also writes about e-bikes for our sister publication ebiketips. He's won three mountain bike bog snorkelling World Championships, and races at the back of the third cats.