Trail Tested: SRAM Guide RSC brakes



The long awaited change to SRAM’s brake line is finally here. Don’t look for the Avid name or the usual XX or X0 style designations, the new brakes are named SRAM Guide, and model level is identified by features rather than drivetrain family. We received one of the first sets available back in May of 2014 to begin long-term testing.

Because of issues with the TaperBore master cylinder design from previous brakes, SRAM now uses a cup seal and timing port to pressurize the system, along with improved sealing throughout. As a result, the recurring problem of air getting into the braking system and causing the lever to pull to the grip should be eliminated.

“Part of what led to an occasional increase in deadband with previous designs was the EPDM (ethylene propylene diene monomer rubber) bladder. As pads wear, fluid from the reservoir is pulled into the increased space behind the slave pistons at the caliper. The displacement of fluid creates a bit of a vacuum in the reservoir,” said Duncan Riffle, SRAM’s MTB PR coordinator. “The new Pure bladder’s flexibility does a great job adapting to this situation and minimizing the vacuum effect. Previous EPDM bladders had a bit more ‘spring’ to them which meant they were trying to ‘pull’ fluid back into the reservoir from the caliper when the pads wear, which in turn leads to inconsistent rollback at the slave piston and then potentially a change in feel at the lever.”

But the changes didn’t stop there. Our Guide RSC (which stands for Reach adjust, Swinglink, Contact adjust) is loaded with features. Starting with the Swinglink, a new cam shape at the lever lessens deadband for minimal lever throw before pad contact. It also changes the curve compared to previous Avid brakes for a very linear feel that ramps up strongly yet controllably. A new sealed bearing at the lever pivot also provided a silky smooth feel. Tool-free contact point adjustment and reach adjust allow you to quickly and easily personalize the feel and performance of the brakes before or during a ride.

The 4-piston dual-diameter caliper carries over from the Elixir Trail brakes, and is just four grams heavier than previous double-piston, cross-country-specific Avids. Total weight per brake for the top tier Guide RSC averages 375 grams, depending on hose length, making these ideal for cross-country, enduro and all-mountain riders.

Once installed, dialing in the feel takes minutes. I have found myself on occasion slightly adjusting the front brake’s contact point to keep it matching the rear—usually within the first half hour of a ride if the bike has been sitting for a day or two. It’s quick and easy (I don’t have to stop pedaling) but it is something I’ve noted.

On the trail, these are easily the best brakes the SRAM group has released. The levers are nicely shaped and pull is incredibly smooth, with a strong yet predictable initial engagement that continues to come on powerfully without ever being grabby, even at slow, poke-along speeds in rugged terrain where careful braking is required. High speed stopping is also strong and seamless with no tendency to lock up the rear wheel. This is how brakes should work—never having to think about what they’re doing or going to do. Adding to this is the new Centerline rotor that completely eliminates squawking with a new surface that keeps the pad friction point consistent throughout rotation.

After nine months of testing it’s becoming clear that SRAM has a brake that finally rivals or possibly surpasses its main competitor in both function and price—they’re going for $199 per wheel. We’ll continue to use and abuse our Guides (we have three sets among the staff)  to see if they maintain this excellent performance. Thus far, we expect they will.

Look for more disc brake tests in Dirt Rag #183 when it hits newsstands and our online store later this month. Or quit putting it off and order a subscription and you’ll never miss one.