TRP's Parabox brake system uses a combination of mechanical brake levers and hydraulic disc brakes. Photo: Jim Merithew/Wired.com

Cyclocross riders itching to take advantage of now-legal disc brakes might like this novel hybrid setup from TRP.

TRP’s Parabox hydraulic brake system for cyclocross bikes is compatible with existing mechanical brake levers and should serve as a nice stopgap for racers who can’t wait for the first fully hydraulic ‘cross systems.

Parabox centers on a master cylinder that mounts on the steerer tube, just below the stem. (It requires a disc-specific fork.) Short lengths of standard brake cables run from the brake levers to a plunger in the master cylinder, which then feeds into the brake calipers via hydraulic hoses.

The result: The power and modulation of hydraulic brakes with the familiar ergonomics and function of existing mechanical brake levers. (That’s the theory, anyway: We saw the brakes at at last month’s Sea Otter Festival bike expo, but we didn’t get to test them.)

Parabox will be available in July and will be offered with either 140 or 160mm rotors. Pricing hasn’t been set but should, according to TRP, come in under $500. The reservoir mounts on the steerer in place of a standard 20mm spacer.

The setup will weigh about 250 grams (8.8 ounces) more than a standard rim-brake system. But that doesn’t factor in what will happen to bike weight and performance once wheel manufacturers start producing disc-specific rims. Engineers are no doubt salivating at the possibilities if they don’t have to build thick, heavy brake tracks into rim walls.

The reason for the scramble and the uncertainty is the announcement last summer by the UCI, cycling’s governing body, that it would permit the use of disc brakes in cyclocross. Already commonplace on mountain bikes and even a lot of commuter bikes, disc brakes are more powerful and reliable than rim brakes, especially in the wet, dirty conditions of cyclocross. And then there are all those possibilities in wheel design.

Parabox will appeal only to the earliest of adopters. But until component manufacturers figure out a way to work hydraulic reservoirs into standard brake/shifter bodies (it’s coming), it’s a compelling look at what the future holds not only for cyclocross but, we hope, for road bikes in general.

TRP had a sweet Stevens road bike set up with its hybrid disc brake system (note the master cylinder under the stem). Photo: Jim Merithew/Wired.com