Ashima’s got some new hydraulic, pistonless road brakes in their design queue.  Dubbed the PanCake Brake (PCB), it uses the same PanCake design of their forthcoming pistonless mountain bike disc brakes.  The hydraulic line feeds directly to a diaphragm seal that holds the pad, eliminating the traditional piston, reducing weight and complexity.

ashima-pistonless-hydraulic-road-bike-brakes2 The system operates using a normal brake lever, with cables (just visible at the top of the image above) feeding into the stem, which houses the master cylinder.  From there, the hydraulic lines run through the steerer tube and fork crown, giving the system a very sleek appearance…for the front anyway, no word on how this’ll be done for the rear brake.

Contributing to that sleek appearance is the one-piece carbon arch/arms construction, which also makes it potentially very lightweight.

Price and weight are unknown yet, other than to say “expensive” and “lightest weight of any system on the market.”

BikeRadar has more photos (including these two) and details.


  1. after looking at photo #11, it seems that there are two master cylinders in the stem (one for front, one for rear) that share one reservoir.

  2. yeah, but where are the hydraulic lines going to run? They’re already having to use a proprietary stem to house the cylinders, but they’d have to run the rear line along the outside of the frame for a bit, otherwise the tight turning (especially in a wreck) wouldn’t really let them run it internally from the stem all the way into the frame.

  3. How do you get a wheel in there? If the pads only have a few millimeters of travel then they must sit within that distance of the rim which means they can’t open wide enough to get an inflated 23 or 25mm tire between them. I wouldn’t want to be forced to deflate my tire every time I wanted to remove a wheel.
    On BikeRadar, someone mentioned this would be good for Cross riding or MTB but the tire width problem would make this impossible. Is there a secret hinge I can’t see in the pictures?

  4. the clearance issue can be resolved easily with a quick release to the mount system at the fork for the cross member. just a thought. Also another thought, could a mount system be made to integrate into the fork for an oversized fork (like the scapula/fibula)? I love this idea!! Another thought, put the resevoir in the steerer tube with the lines and have completely internal line (for the front). I have integrated handlebar/stem and the only hole needed would be to the steerer tube (it can handle that!)! Be happy to try it out!

What do you think?