The new OutBraker Brake Power Booster is a clever, adjustable inline reservoir that gives you more control over your hydraulic disc brake’s power. Perhaps even more useful, it also gives you the ability to adjust the pad contact point.

And, they say, it’s a universal fit and will work on any brand of brake, for road and mountain bike brakes. Here’s how it works…

The Brake Power Booster is a secondary reservoir that’s added inline on your hydraulic disc brake system. For mountain bikes, it’s added just behind the lever. For road bikes, it’s added just above the caliper. Both function the same way.

how does the outbraker hydraulic disc brake power booster work

It works by giving you the ability to adjust the amount of fluid that’s actually inside the hose at any given point. Twist the adjustment knob one way and it reduces the size of its reservoir and pushes more fluid into the hose, thus moving the pads closer to the rotor and, presumably, adding more power because you’ll have more lever to pull and really clamp down on the rotor.

Twist it the other way and it holds more fluid so there’s less in the hose, and you’ll have to pull more lever to squeeze the pads as hard.

We see the benefit coming more in the ability to adjust your pad contact point. This could let you really dial in the lever feel, and potentially increase leverage over the last bit of the braking point before it simply locks up and skids the wheel. It’s also a great way to adjust for pad wear, even those most high quality hydraulic disc brakes use a lip seal that does this automatically.

What’s the difference between Pad Contact and Free Stroke?

outbraker inline hydraulic mountain bike disc brake power adapter lets you adjust the pad contact bite point

Remember when you brakes were cable actuated and you could dial in that barrel adjuster to move the pads closer to or further from the rim or rotor? That’s what the OutBraker Power Booster does. By adjusting the size of its auxiliary reservoir, it’s either adding or subtracting fluid from the actual brake hose. If it’s adding fluid, the pads will be pushed closer to the brake rotor, and vice versa.

Free Stroke, which some higher end brake levers have, simply adjusts the valve’s closure point within the lever’s master cylinder. By moving it farther from the master cylinder’s port, it lets you pull more lever before it closes the circuit and starts pushing fluid down the hose toward the caliper. So, if you (for some strange reason) like the brake lever to move without actually doing anything, then find one (like the Shimano XTR levers shown here) that offers Free Stroke adjustment.

Outbraker Brake Power Booster specs

outbraker inline hydraulic disc brake power booster for road bikes and mountain bikes

The part is made out of aluminum and steel and works with Shimano, SRAM, Magura, Tektro, Formula (2nd edition only) and Hope (Pro edition only) brakes. They say the boost range is up to 180% of the original power. Claimed weight is just 22g. Retail is $179, available now on their website. From the looks of it, this one replaces the prior model with the red adjustment knob as that one’s showing as both discounted and out of stock.

outbraker inline hydraulic disc brake power booster for road bikes

This isn’t their first hydraulic brake power adjuster, but it’s definitely much sleeker than the original, and now it works with drop bar brakes, too. Outbraker also makes dual hose adapters, letting you work both brakes from a single lever (great for folks with special needs), as well as inline anti-lock braking systems.


  1. Please don’t use these on your open system disc brakes. It over fills the system, rendering the reservoir useless to manage heat and fluid expansion. Bad for the brake and the rider.

  2. Changing the volume of the hose does literally nothing to change the leverage ratio of a hydraulic system. All this does is push the pads closer to the rim, which has zero effect on actual braking power. I mean, you can accomplish the same thing by taking out the wheel and putting a slightly thinner spacer between the pads and grabbing the brakes. There, I just saved you $360 and your friends that know anything about hydraulics won’t mock you relentlessly.

  3. Great. You can have the dial all the way out, install and bleed the system, turn the dial all the way in, and blow a hole in your formerly-functional reservoir bladder.
    They suggest it’s to compensate for when your pads are worn. The open system should self adjust. If it doesn’t, most likely your caliper pistons are dry and over-retracting. Move the pistons around and they’re fixed. No stupid dial.
    At first I thought this was going to be like Formula’s bite point adjuster (which I think is dumb but at least it does what it’s supposed to). Nope.
    This thing is terrible.

    • …but it’s expensive and looks neat. “Look folks, I got a dial thing on my brakes!” . I’d pay up to 89 cents for such a thing. Maybe even go all the way to a buck.

  4. Terrible scam technology…. in my opinion. I don’t see how this device can boost braking power 180%. 100% of any hydraulic brake is more than enough braking power already anyway. It may change the pad position but that does not change braking modulation. It only changes when the brake will start to engage, at best.

  5. it changes the amount of fluid in the line. jesus that’s impressive, so it can create a vacuum of some sort . this is such BS

  6. It won’t even adjust the pad contact point, will it? Except if the original reservoir is filled up all the way, it will just fill that one up and the pads won’t be moving at all. It’s really crazy someone is actually trying to sell this and even more so bikerumor is presenting it like a functional device.

  7. I fully agree with previous comments. Bikerumor is a much used source for information for lots of bike enthusiasts. Wouldn’t it be fair to add some form of a “fact checker” to articles like this?
    Look at dcrainmaker. He does a similar thing in an always respectful manner. Wouldn’t it be fair to call this what it is, without being insulting? Technically senseless and expensive without any form of added value?

  8. No No No No No No No No No No No No No No No No No No No No No No No No.
    That you legitimise this BS is beyond embarrassing.Yes you are desperate for content but really? Try and exercise some editorial integrity.

  9. Here’s an idea… buy a set of brakes with contact adjustment already built in… like, for example, Sram Guide RSC’s (which work great!)

  10. Inline Hydrologic Brake Contact Adjuster. There, fixed the title… When my pads became worn, I would just pressurize the system with my bleed syringe.

    • I’ve done that somewhat during initial setup, but just fair warning, I’ve spoken to TRP, SRAM and Shimano about this and they mostly do NOT recommend it. SRAM’s master cylinder design is more forgiving when doing this than the other two, which is why both Shimano and TRP recommend a gravity bleed procedure that pushes fluid down through the caliper. SRAM’s bleed procedure does push fluid up to the master cylinder, but with any of them you do NOT want to push to hard on the syringe and over pressurize it during setup…here’s why: It can collapse or compress the diaphragm that’s used to allow for heat expansion, which leaves your closed system with no room for the fluid to expand, which will create more immediate brake pump.

  11. Hello everyone, and as always, thanks for reading. Why do we cover something like this? Because it’s interesting. Should you buy it? Or even like it? That’s entirely up to you. Our goal here is simply to cover all the latest and most interesting cycling products, tech, components and bikes and present the information so you can make your own decisions.

    As stated in the article, probably the biggest benefit to this is using it as a form of pad contact adjust, and admittedly it’s a very expensive way to go about getting it.

    That said, if, for some reason, your brakes end up pumping up and force the pads into contact with the wheel and make it unrideable while you’re out on a ride, this offers a safety net. Might be of interest to people out on multi-day or longer bikepacking adventures where having some measure of control in case their lines get contaminated and either lose power or get pumped. We’ve had this happen on an older set of brakes before, and something like this would have let us finish the ride with both brakes working. Instead, we had to remove the pads from the rear and finish with a single brake. Crap happens.

    When appropriate, we do try to put things into context, and I believe I explained how this product works and what potential benefits it offers.

    With regards to leverage, there’s such a thing as “perceived leverage” that has a great deal of impact on how the levers feel…in my opinion. Let me explain. If the pads are super close to the rotor and you can only pull the brake lever a tiny bit before they’re locking up the wheel, you don’t have very much leverage (read: control) over the braking forces. You can also think of this as “modulation”. But if you add space between the pad and the brake and therefore create more lever throw, it lets you modulate the amount of braking force used with finer detail. Perhaps my use of the word “leverage” wasn’t the best choice, but this is how I perceive it.

    • Why cover it? Clicks = dollars. We get it, you run a business and don’t begrudge you that. But your response makes it clear this thing is a bodge. You seem to have no lack of content. Covering this garbage is beneath you.

      • Seriously, what else do you expect? BikeRumor is not a subscription content service, as such they are dependent on clicks. In addition, let’s go back a few steps. What is the title of this bike related news website… BikeRumor!… This news outlet does what it says: it centers around bike related rumors, with everything that involves. This is what it does, this is why we come here to read, and nothing else is promised – and as such nothing else can reasonably be expected. If a product (a) has the potential to generate clicks, and (b) is part of the grapevine; then it qualifies for the website. Don’t blame BikeRumor for failing to live up to YOUR expectations.

        For the record I’m a happy reader. I think they do an excellent job considering I’m not paying for the content expect with my time looking at their advertisements. I have no complaints. If I don’t like what they write and do, then I move on to another news outlet. Simple as that. 🙂

  12. so basically its a ridiculously expensive bite point adjuster…….. There should be a law against selling things for what they are not

  13. Absolutely insane that bikerumor pushes this as newsworthy, shame on you for spreading this scam.

    You should retract and apologize to your readers, this is dumb like a bag of rocks.

    • Mr. Benedict, what you’ve just written is one of the most insanely idiotic things I have ever read. At no point in your rambling, incoherent response were you even close to anything that could be considered a rational thought. Everyone on this site is now dumber for having read it. I award you no points, and may God have mercy on your soul.

  14. Man, and I thought politics was inflammatory these days…
    This is an awesome product out there for people that only like to geek out and tweak things and constantly feel the need to adjust the lever throw, i.e. myself. I really don’t care if I damage the brake by over filling the system… I’ll just go buy a new one.
    Take a chill pill and realize the cycling and mtbing are creative and stress reducing outlets for the vast majority of people, and getting all worked up about what Bikerumor things is news worthy is a waste of time.

  15. What about buying a pair of SRAM RSC or top of the line Magura or Hayes??? the only companies missing these benefits from the design table are Shimano and TRP

  16. Was desperate to comment on this but it seems everyone has come to the same conclusion, it’s total rubbish, how can it work…. If your able to push the pistons back when you change the brake pads then the master cylinder has the ability to absorb excess fluid in the system…. Rendering this totally useless surely

  17. Here’s how to write the article:
    “New product from so-and-so, claiming to be a power booster for your brakes. We’re not entirely sure how it’s supposed to work. Based on the diagrams and presentation, it’s an adjustable fluid reservoir inline with the hose. That seems to us like it will only adjust the volume of fluid in the master cylinder reservoir, nothing more. We’ve reached out to the manufacturer for clarification. Stay tuned.”

    • That kind of attitude won’t win you new advertisers, Greg. (But that’s exactly how snake oil should be handled.)

    • That presupposes an an ability to parse the mechanics of a product outside of reading and rehashing the press release. I don’t see a lot of that here.

  18. Jeez, what a load of hand wringing here. OK, it doesn’t really offer much in the way of benefits, while also introducing some drawbacks. We get it. You’d think this thing causes pedophilia, based on some of the comments.

  19. Is this “covering” something Tyler or just regurgitating a PR person’s marketing spin?
    Why bury your take on it down in the comments instead of as the footnote in the article…. And you do in your comment call it an article not a marketing media release.

  20. Chill out folks, this isn’t worth the vitriol you’re spewing. Is everyone in riot mindset or what? I appreciate the content that BikeRumor shares even though some of the products will be hits and some misses. Chime in when you have helpful perspectives, but be nice. We all get saturated with political nastiness these days but I hope we can keep cycling healthy, friendly, and fun.

  21. The world of physics must have changed. As far as I knew the majority of most fluids were not compressible. All this trinket does is pre-pressurize the line and coincidentally in the same breath tweak the travel for you.
    I am sure that it does work and the system can take it just be ready for that quick bite now that all the slop of the system has been removed. But then again adding pressure to a relaxed and static system is usually not a good thing for the rest of the components.

    • You’d be wrong if you assumed that most fluids aren’t compressible. You might want to read the wikipedia article on Bulk Modulus.

  22. Holy hell. I was just telling my wife how I wasn’t going to read the news until at least September…. anger is infectious and has infected everything. Good grief. Who cares? To have enough time to get that worked up about a brake lever…. ooof. Wish I had your time, fellas!

  23. Can you explain how this will let you adjust the bite point in an open system, i.e. with a reservoir? As soon as I let go of the lever, the reservoir is connected to my brake line. this means that the fluid pushed into the line will primarily fill up the Reservoir. The only way this might work is if i push the lever in while adjusting the new system, then hope the reflux generated by the lever will not return the pistons to the initial position but slightly further in. This would be really unprecise and difficult to set up.

  24. What a scam. It does not boost your power at all. It does not do anything at all in open systems. Come on Bike rumor, protect you reputation but keeping utter crap like this off your pages.

  25. I think the point is that you can “tighten” the system up after you’ve bled it.
    I’m not sure i’d really want to ever run my pads Closer than default, but, that’s what this allows you to do.

  26. I just wish they’d drop the godawful puns for good. I’d click on way more articles if i wasn’t so repulsed by the headlines.

  27. And Saint. I should know. I adjust it twice a ride these days. The knee in the ServoWave track is right on the threshold of where I like my adjustment, so it takes almost nothing for the adjustment to migrate either side.

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