A new marathon course isn’t the only thing being debuted this week at Challenge Roth. Today in Germany, a few days before SRAM debuts its new hydraulic disc TT braking system, the S900 HRD brake lever and road caliper set.

The debut is SRAM’s triathlon and TT-dedicated product to address the new market of disc brake bikes. To this point, many of these bikes have had mechanical or a hybrid disc braking system. Now, a hydraulic disc option is on the table.

“Consistent braking in all conditions, it’s the perfect setup. I think once people try disc brakes, and experience the, they’ll realize how much they want it,” said Declan Doyle, marketing manager with Zipp and SRAM. “The future of the bicycle—for both road and tri—is with disc brakes.”

The front brake flat-mount caliper.


The S-900 Aero HRD setup starts at the top with the brake levers. Here, the lever features a textured carbon lever, which is reach-adjustable to accommodate various hand sizes.

The master cylinder block rests out front of the basebar, and acts as a stop for the hand (which can be beyond helpful when the hand is jarred over a speedbump or slips on wet roads).

Shifting is independent of the lever; for those that don’t have electronic shifting can run their mechanical shifting setup (SRAM’s R2C mechanical shifters or any other cable-actuated shifter) while still enjoying hydraulic stopping power.

The rear flat-mount disc caliper, as applied to Zipp’s 900 carbon clincher disc/disc.


The flat-mount-only calipers will be available with 160 or 140mm CenterlineX rotors.

Aluminum pistons and an aluminum heat shield living at the back of the caliper absorbs heat buildup, preventing the caliper body from heating up.

SRAM’s Bleeding Edge fluid bleeding system is fairly simple, at least by hydraulic bleed standards; a hex head is unthreaded a quarter-turn, and DOT fluid can be syringe-pushed into the system. The port rests at the highest point for the rear brake, allowing air to purge naturally from the system. The front will require a slight tilt of the bike to allow for air to bubble out.

Setup includes SRAM’s Stealth-a-Majig connectors.


Lucky us, we’re here in Roth to check out the new goods in hand at the SRAM expo. Probably the biggest conjecture is how it organically feels in hand. While the squared knob at the front of the brake (which houses the master cylinder) seems obtrusive, it’s functionally integrated, and practical, acting as an stop in the event of hand slippage. In the hand, it feels safe and solid. One won’t put their hand over the master cylinder block, so certainly, measuring where you want the lever to be in relation to the basebar plug-in may vary in comparison to your existing setup, meaning a potential basebar cut-down. Or not. Your (or your fitter’s) job to determine.

As for stopping feel, the lever pull on the unit on display here at Challenge Roth has that solid smoothness that is hydraulic stopping. As stated, the lever itself is reach-adjusted by a small 3mm bolt, accessed through a slot at the front of the lever.

The carbon fiber lever features a raised ribbing for a bit of textured bite for the finger to get purchase upon.

The other conjecture is whether disc is necessary for tri.  SRAM’s elevator pitch is that it’s safer and has better feel that will make for an athlete with greater confidence that brakes later. Marketing spin? No way.

As a frequent mountain bike racer, I’ve come to have a fully enamored experience with hydraulic braking. It’s a much more positive feel, with less muscular force to actuate. That means you can trust when you put, that the feel will be linear and reliable from the beginning to the end of the squeeze. That in mind, I typically brake late, especially in adverse (wet) conditions. With rim brakes, there’s often a need to “drag” the brakes on a tri bike on wet roads heading into a corner, especially on tri bikes with aero calipers that have compromised stopping power.

Hydraulic disc braking doesn’t require that drawn-out brake drag. And the less you’re on the brakes in the wet (or in any conditions, for that matter), the less you have a chance of having a tire slip. Ride more confidently, brake late, reduce chances of wrecks, go faster.

The inboard brake point can run SRAM’s eTap blip, or nothing if running a mechanical bar end shifter setup.

It’s a more positive feel with less muscular force to actuate, which means for more confident braking, later braking (and less braking). Spend less time out of the aerobars braking and voila—you go faster. By SRAM’s estimation, disc braking becomes a faster rider. It seems on its face to be a bit of a stretch, but in our world of splitting seconds, there’s truth to it.

SRAM staff says its own testing is beginning to debunk the notion that disc brakes is an aero drawback. It may be to a degree, but it’s negligible, they say. “The aero drawback is fractional,” says Jan Mueller, SRAM’s European PR Technical Coordinator.  “The benefit in braking improvement massively outweighs any aero penalty.”

A look at the bleed port bolt at the lever.

And to be totally fair, SRAM is in its infancy of disc brake development as it applies to tri bike integration. Over time, we expect to see much cleaner integration of the caliper (and perhaps even rotors) into the construct of the bicycle.

This debut means that SRAM is fully committed to disc brakes in tri, which is in lockstep with their push in the road market. They’ve beaten Shimano (and certainly Campagnolo) to the punch, and we are near to testing one other hydraulic TT/tri shifter about to hit the market this fall from Tektro.

Right now, there are four major brand models we’re aware of (Cervelo,’s P5X, the Cannondale Superslice, Diamondback Andean and Parlee TTiR) that are offering disc brakes on triathlon bikes. We are hopeful that the fall Eurobike and Interbike reveal a few more. And more after that. In our opinion, disc brakes will be to rim brakes as carbon clinchers are currently to tubulars. The braking is better, safer and for tri, the calipers will become more aero. It won’t happen overnight, but it’s gonna happen.

Availability? This September. Pricing: The brakeset will price at $249. Rotors will price at $72.