When most people think of hydraulic brakes on bicycles, they probably picture modern mountain bikes with disc brakes. As early as 1987, however, German bicycle component manufacturer Magura was making hydraulic rim brakes for mountain bikes. These featured the arms and rubber pads that we currently associate with V-brakes and cantilevers, but they were hydraulically activated. Now, 25 years later, Magura has released an aerodynamic hydraulic rim brake system for lightweight time trial and triathlon bikes.
The new system is called RT8 TT - RT for Road Team, and TT for Time Trial.
In order to get the aerodynamics just right, Magura collaborated with Cervélo, the Canadian high-end road bike manufacturer. Cervélo is known for its research into bicycle streamlining, and in fact recently unveiled what it claims is the world's most aerodynamic time trial/triathlon bicycle, the P5 ... which has integrated RT8 TT brakes.
The system consists of carbon fiber levers, joined by sealed-system hoses to "extremely stiff" aluminum brake bodies. Flowing through those hoses is Magura's wonderfully-named Royal Blood mineral oil. Unlike the DOT braking fluid used in many mountain bike systems, it apparently doesn't need to changed, and is non-toxic. Like those other systems, however, RT8 TT is said to be essentially maintence-free and impervious to dirt, dust and water. The pads will still need to be changed, but this is a relatively simple procedure.
Low maintenance is nice, but according to Magura, the big selling features of RT8 TT are its high braking power, fine modulation, light weight and aerodynamics. Friction losses are reportedly minimal, meaning that even a slight touch of the levers will activate the bodies. Weight-wise, the entire system tips the scales at 495 grams. For comparison, a complete Shimano Dura-Ace TT/TRI cable-activated brakeset is 381 grams, not including cables and housings.
The Cervélo P5 will be the only bike to feature RT8 TT for the 2012 racing season, but it should be available for use on other makes of bicycles after that. Deep-pocketed cyclists can purchase the system on its own as of this June, for EUR 599 (US$770). For EUR 499 ($642), they can instead go with the aluminum-levered RT6 TT system. In the near future, Magura will additionally be introducing the RT8 mechanical-to-hydraulic converter, for installing the hydraulic brakes on bikes with existing mechanical levers. A cheaper RT6 converter is also on the way.