MTB Review: 2011 Avid X0 Hydraulic Disc Brakes

SRAM has been busy over the last year or two integrating and simplifying product lines across their brands (SRAM, Avid, RockShox and TruVativ) to offer true component group selections for mountain bikes. SRAM helped me set my bike up with the X0 component group this past fall which includes the freshly-designated XO hydraulic disc brakes.

Tech and materials

For those who are familiar with the Avid brake line, the XO brakes essentially take up where the Elixir CR brakes leave off (though the Elixir CRs are still considered the X9 brakeset). Based on the specs available online there isn’t much difference between the X0 brakes and Elixir CRs – except for the fact that the X0s weigh 40 grams less! The X0 brakes come equipped with slightly different brake pads (organic vs. sintered) and a more streamlined master cylinder.

The Avid X0 brakes tip-toe onto the scale at 333 grams which is lighter than most hydraulic disc brakes out there (though somehow the XX version is nearly 50 grams lighter than that!). SRAM was able to get the weight down thanks to carbon levers and a sleek in-line master cylinder and reservoir design that’s not only lightweight, it also takes up very little space on your bars. The lever body and caliper feature durable aluminum bodies.

Installing the X0 brakes is a cinch and aligning the caliper and rotor is literally a two step affair: 1. squeeze the brake lever and 2. tighten the bolts. That’s it. I’m not mechanically inclined myself but I installed these brakes in about 30 minutes and had them spinning rub-free on the first attempt. I found the standard hose length to be more than adequate; in fact, even on my large 29er I ended up with a bit too much hose up front (I haven’t found the time to trim the hoses to length yet).

The brake pads on the X0 brakes are top-loading which means you don’t have to remove the wheel to replace the pads. This might seem like a minor detail but it could come in handy during a race like last year’s Fools Gold 100 where competitors burned through multiple sets of brake pads due to gritty and wet conditions. And finding replacement pads at your local bike shop shouldn’t be an issue since the pads are fairly standardized across the SRAM/Avid line (unlike other brakes we’ve used).

On the trail

Let me start this by saying: these are the best hydraulic disc brakes I’ve tested. The first time I used the X0 brakes on the trail it was like a revelation – this is how mountain bike brakes should work. The levers feel completely comfortable and natural and easily lend themselves to single finger pulls (something I’m finally getting used to). It turns out SRAM has put a lot of thought into the placement of the lever pivot (closer to the bar) to align more closely with the arc your finger makes as you pull the lever in.

I also really like the positive clicking sound and feel whenever I release the lever. I’m not sure if there’s a real performance reason for this (like letting you know the brake is fully disengaged) but it feels solid and satisfying on the trail. Contact point adjustment is built into the master cylinder with barrel-adjuster type controls which helps tailor the lever feel and performance to each individual (and helps compensate for pad wear over time).

From day one my X0 brakes have been whisper quiet on the trails and I rarely experience that spaceship warbling sound I notice when others grab the chicken switches. The included rotors are mated perfectly to the pads and after 6+ months of riding in all kinds of conditions (wet, gritty, hot, snowy) I still have some wear left on the first set of pads.

One of the key performance metrics for any mountain bike brake set is modulation and in my experience the X0s offer smooth, regulated stopping power that’s easy to throttle from a little to a lot while screaming down the trail. SRAM talks about something they call “Deep Stroke Modulation” which is heavy on marketing-speak and light on actual technical details but honestly I don’t care – the ability to control braking power on the X0 brakes is both intuitive and consistent. As far as I can tell it’s just magic.

In keeping with the idea of providing a true mountain bike component group, SRAM offers the X0 brakes in multiple color ways (red, blue, gold, and black). The shiny black finish, which SRAM calls “Black Onyx,” looks hot but it’s also great at shedding mud and cleaning up after a dirty ride. No need to spray these parts with Pam – they’re already slickity slick.


If you haven’t guessed by now, I love the Avid X0 brakes and would recommend them to anyone building up or upgrading an XC/AM bike. To me, the best bike parts are easy to install (check), low maintenance (check), and don’t get in the way on the trail (check) – along those dimensions Avid’s X0 brakes are 3 for 3. Go ahead and give the X0 brakes a shot – what’s stopping you?

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