TRP Aaron Gwin prototype four piston downhill mountain bike brakes

TRP only started working with Aaron Gwin in February, after agreeing to his terms. They say Gwin didn’t just want a sponsor throwing cash and product at him. He wanted someone that would take his input and actually tweak things throughout the season.

They started with the levers, putting other parts from their existing inventory. From there, they printed rapid prototypes to get the shapes for Gwin to feel. Then they took the ones he liked and produced one-off lost wax sand casting metal samples, then CNC samples until it was final. Then they’d forge the levers and prep for race day…

TRP Aaron Gwin prototype four piston downhill mountain bike brakes

The brakes started with TRP’s Quadiem SL, which is their most powerful brake, then added the revised levers. Gwin likes to brake with just one finger, so this one’s less bendy and has a little less flare, giving it a leaner profile. The reach adjust will have detents to provide a distinct click between adjustments since Gwin likes to double check lever position by counting the clicks.

TRP Aaron Gwin prototype four piston downhill mountain bike brakes
Gwin’s new lever shape (bottom) bends a little differently than the stock Quadiem lever (top).

TRP Aaron Gwin prototype four piston downhill mountain bike brakes

The calipers got a complete overhaul, using the same basic shape. Inside, the tolerances became much tighter to reduce pad play, preventing them from shifting forward during that initial braking. The bodies were custom CNC’d and given heat sink grooves on the top. They’re not something you can buy now, but it’s the basis for an all new brake that’s slated for 2017.

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The T860 direct mount rim brakes are now in production. The roller cam design fits any bike with the two bolt Shimano direct mount pattern, but provide a sleeker, more aerodynamic package.

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The aero cover is removable for service and set up. Each arm is individually adjustable, helping you get the pads evenly spaced even if your wheel is dished a little to one side.

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The Tektro Bleeding Pump is a shop device originally created for the growing number of shops China (but theoretically available to anyone, with a new version being prepped for Europe) that aren’t as familiar with bleeding disc brakes.

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It’s a positive pressure pump, meaning it pushes the fluid through the system starting at the caliper rather than vacuum pulling out up through the lever (which is ideal), but it gets the job done quickly and efficiently to a safe enough standard.

TRPbrakes.com / Tektro.com

9 COMMENTS

  1. Why is pulling fluid out of the lever ideal? Seems like a good way to get air into the reservoir. Granted, I’m only familiar with automobile brake setups, but it’s absolutely trivial to just open a bleed screw on the caliper, and pressure or gravity bleed the brakes by using a pressure bleeder/topping up the reservoir.

    • Some brakes I’ve dealt with do recommend that you bleed starting from the lever. Hope, for one. Most companies however recommend bleeding starting from the caliper, I believe, to have the greatest chance of pushing all of the any air out of the system. Brake fluid reservoirs on cars are much larger, and a greater volume of fluid is moving through the lines, so that may facilitate air moving out of those systems into the reservoir. As for the negative pressure being ideal: I have no idea. Many brake systems have you use a funnel attached to the reservoir (Shimano) or just a hose to a bottle (tektro) to receive fluid when bleeding, which exerts no negative pressure. SRAM’s bleed instructions, however, have you exert some negative pressure using a syringe to receive fluid from the lever. In practice, I’ve found that too much negative pressure causes air to leak into the seal between the bleed fitting (even on the “pro” level bleed kit) and the lever. So I don’t know why a negative pump would be ideal.

      • “In practice, I’ve found that too much negative pressure causes air to leak into the seal between the bleed fitting (even on the “pro” level bleed kit) and the lever. ”

        Exactly. I have the same problem. Even with great care and multiple attempts, elixir brakes (xx) cannot be bled perfectly and worse, after one ride they will feel spongy.

        Shimano – never one problem. Done one bleed and after 4 year of downhill they are still running great.

        I also bled cars clutches cylinders with positive technique – no probs. Used once negative it was a nightmare. No matter what always small bubbles in line

  2. The only reason I can think of as to why negative pressure bleeding may be better is that it might help to “de-gas” the fluid.

  3. Bleeding from the lever/resivior makes Moe sense simply because air goes “up”. Bubbles will more naturally travel that direction.

  4. You’ve simply misread it.
    “it pushes the fluid through the system starting at the caliper rather than vacuum pulling out up through the lever (which is ideal)”
    The “ideal” comment refers to the way it pushes through.

    And was I the only person who read the headline thinking that Aaron Gwin’s brake callipers were aero for DH speed and auto-bled during use? Now that would be cool…

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