SRAM has been producing the Avid Elixir brake lineup for a while now. Perhaps too long. If you’ve ever run a set of Elixirs, or worked on them, you know what I'm talking about. It's not like they’re awful brakes–they have a lot going for them, actually. They’re strong, have a great lever feel and shape, modulate power well and offer phenomenal adjustability–when they’re working. Elixirs are notoriously, shall we say … inconsistent.
The guts of Elixir, a technology SRAM calls Taperbore, requires a perfect bleed for the brake to function properly. Making something airtight in a world full of the stuff is simply not going to happen all the time. Brakes need to be able to manage the air that is bound to wind up on the wrong side of the seals.
So when it came time for SRAM to develop a new braking system, senior mountain bike brake engineer, Braden Snead put the brakes on Taperbore and started from scratch. The result is this brake right here, the Guide. He knew he wanted a more robust brake, so he designed the Guide around a timing port mechanism, a system common to many other mountain bike and motorcycle brakes. If air enters a timing port-type system, the bubbles are directed through the port into the reservoir, effectively self-bleeding the brake. As the brake lever is pulled, a cup seal passes over the port, closing the system, building pressure and advancing the pistons. The air in the reservoir is safely away from this whole situation. If the Guide lever looks similar to the Avid Juicy brakes of the past, that's because it is. Those brakes used a timing port system as well.
But the Guide is a whole lot more than a new Juicy. It's a ground-up design. Probably the biggest standout in the Guide brake is what looks like a tiny suspension link inside the lever that is pushed by a cam. SRAM calls it Swinglink, and it's there to control the amount the pistons move for a given amount of lever throw. Swinglink enables the pistons to travel very quickly at the beginning of the lever stroke but then advance less rapidly. This reduces the time between when the lever is first pulled and when the brake engages (what is referred to as deadband) but does so without creating a grabby, uncontrollable feel. Think about it: If the smallest finger tug turns the brake on, it would be extremely sensitive and difficult to manage. SRAM was able to tune how fast the pistons advance during certain times of the lever stroke, thus lowering deadband, but maintaining modulation.
Swinglink is the magic of the Guide brake
Because of its success, the Guide lever is paired with a rebranded X0 Trail four-piston powerhouse caliper. The lightweight, yet robust, piston features 14- and 16-millimeter pistons to provide amazing power, while again, maintaining power control. For those of you who just read this and got the idea to upgrade your current X0 Trail brakes, sorry, SRAM will not be selling Guide levers only.
There's also a new rotor. The Centerline rotor will be available in diameters of 140, 160, 170, 180 and 200 millimeters, and was designed to manage heat and resist deformation better than other rotors. They'll be offered in 6-bolt at first, with an aluminum-carried Centerlock version following soon after.
Three Guide models will be available in June: RSC, RS and R. The top-level Guide RSC offers tool-free reach adjustment, Swinglink and pad contact point adjustment, and retails for $200 apiece, without rotor or mounting bracket. The $150 RS has tool-free reach and Swinglink, and the R has tool-free reach for $130. If you can make it happen, I'd definitely recommend the RSC because the pad contact point adjustment is fantastic.
We rode the Guide RSC for three consecutive days in Moab and the brake absolutely blew its predecessors out of the water. If you have any preconceptions about how SRAM brakes feel, forget them right now, because there's no comparing the feel of these with any other brake SRAM has made. First off, lever setup is an absolute breeze. For those of you who are picky about lever position and throw, get the Guide RSC. The reach adjustment knob is on the outside of the blade (same as Shimano), which is super-convenient. Once that's taken care of, dial in the contact point using the indexed 'Wheel of Fortune' knob, which has a nice wide range of adjustment. I personally like to set my reach very close to the bar, which normally means I need to employ some fancy bleeding techniques to achieve a short enough stroke so I get braking power before the lever bottoms on the handlebar. Thanks to the Swinglink, I managed to achieve my picky setup with zero fuss.
On the trail, performance was outstanding. There was plenty of power, but none of the grabby feel that can be associated with Shimano Servo Wave brakes, such as XTR Trail, XT and SLX. Despite my love affair with Shimano brakes, I've always felt that they're difficult to control braking power, winding up in unintentional wheel lock-ups, especially in loose conditions.
The Guide brakes offer incredible stopping power with unmatched modulation, providing excellent bike control. Pad clearance is very good, and the new Centerline rotors worked without any of the telltale SRAM warbling or squeal. I rode the metallic pads, which remain unchanged, but SRAM is also offering a new organic pad compound that is said to run quieter, while offering better power than previous organic compounds.
After three days of hard riding, there was no brake rub or warped discs on my test rig. Conditions were typical desert-style, with dry, dusty trails, loose sand and no moisture in sight. I'm anxious to get test these brakes in wet conditions.
Unlike the mystery grab of the Elixir brakes¬–when you're never quite sure where in the stroke the brake will turn on–lever pull and contact point remained incredibly consistent with the Guides. No trailside adjustments were needed to account for erratic feel. They stopped perfectly every time, with a crisp, solid, mush-free feel.
In the end, the reliability of a product comes down to manufacturing. Making one badass brake is hard enough, but making a million of them is a whole different story. With Guide, engineers were able to design a platform that will tolerate sub-perfect bleeds, and have worked to improve quality control. Let's hope these efforts pay off because this brake has serious potential. Look forward to a long-term test in the future.