SRAM unveiled its hydraulic rim and disc brake systems at a launch in California last month. The technology sees the American manufaturer become the first to market with such a system and potentially steal a march on its more established rivals.

SRAM had previously lost ground to Shimano and Campagnolo in the technical stakes as both have electronic and 11-speed groupsets, but now they can boast a genuine first.

Named Hydro Road Rim (HRR), SRAM’s new hydraulically actuated 
rim brake houses the master cylinder 
in the hood bulge but has the exact same dimensions in the body as the 
previous version.

With the bulge of the hood gaining about 10 millimetres in height it’s certainly very noticeable, but the extra size is soon forgotten when seen in use.

From the master cyclinder, the brake hose, which has the same outer dimension, 5mm, as standard brake outer is routed around the inside of the hood and run to the brake in the normal way.

By mimicking a standard cable outer the brake should be compatible with most frames, for those without internal routing you’ll need a brake line guide.

Rim-pressive design…

By using a single piston on the HRR SRAM was able to replicate the look and, all-importantly, the standard single-bolt fixing of a conventional road caliper. And despite being a little bulkier than a normal caliper, the hydraulic version has a similar profile so we can see no reason why it shouldn’t fit almost every bike currently available.

HRR will operate just like any mechanical brake, but should require less force and offer greater overall stopping power, making it ideal for those with smaller, less powerful hands or when conditions mean you need to exact more force on the rim. Plus, of course, being a sealed system it’ll be much less affected by the ingress of dirt and road salt.

Hydro road disc

Using the same shifter as the HRR version, HRD or Hydro Road Disc, is more than three years in the making. As SRAM already has a lot of experience with hydraulic disc brakes from its mountain bike business, Avid, you might expect the road version to be a simple lift, but SRAM’s engineers insist that the different requirements for road use are significant and meant that it had to design a new system from the ground up.

Using the body of the hood as the case for the master cylinder is central to the design. The pulled brake lever pushes a plunger up inside the extended hood and the displaced oil is driven down the hydraulic hose to the caliper at the hub. Interestingly SRAM has created a twin-piston disc brake – this is significant as it would have been far cheaper and quicker to have made a single piston with a floating caliper but it’s a cheap solution and one it didn’t feel would be appropriate for the top-of-the-range Red groupset.

… and new disc-overies

The standard disc is 160mm with a lightweight version also available which will measure 140mm. Several mounting options for the discs will be available too so that different hubs can be used.

With no danger of crushing the wheel and heat build-up not presenting the same challenges as it does on the rim, the disc brake can be much more aggressive, meaning the force at the lever is less yet the overall stopping power is greater

Red clicks up a gear…

On its own, the addition of the 11th sprocket to the Red cassette would have been a big deal. Necessitating a full redesign of the internals of both the shifter body and the cassette, every area had to be looked at up close with even the grease used having to be altered to make sure that the same outer dimensions of the shifter remained; in fact without the logos you’d never know about the extra click. The double-tap shift mechanism remains.

By adding that extra sprocket, both derailleurs, chain and obviously the cassette itself needed to be revised. SRAM has wisely not tried to set its own standard with this but has stuck with the 131mm hub that came in with Shimano’s 11th sprocket.

Red alert: Cranked up to 11

So the slightly wider cassette requires a narrower chain, which in turn meant the front mech had to be narrowed. At the rear the mech needed to be able to swing slightly further so received just a couple of minor tweaks, allowing it to span the wider range.

10-speed lives on …

If you’re already a user of SRAM and think you’re being left out then SRAM has something for you.

Launching at the same time as HRR and HRD, comes the not-so-catchily named non-series S-700 HRD and HRR. In essence S-700 is a 10-speed version of the all-singing all-dancing hydraulic offerings.

Using the same hood shape but with 10-speed internals, S-700 is compatible with all current SRAM road offerings. We think that S-700 HRR will be among the hottest items in your local bike shop this summer.

A new Force of inspiration …

Not content to have added an extra sprocket to the Red groupset, Force has also been taken up to 11. Running on a timeline that is about a month behind Red 22, Force gains the vast majority of the technology from the top-end offering, but through a choice of materials and finishes manages to reduce the cost greatly without compromising the longevity of the groupset.

Lifted straight from Red are the ergonomics and shape of the shifters, as are the internals, but the carbon brake lever is swapped for an alloy version. The front mech gains the ability to swing in yaw so the trim function on the front mech is no longer required while at the rear the jockey wheels are upgraded to AeroGlide for quieter running.

As with Red 22, the cassette on Force gains a 16-tooth sprocket to give one tooth increments from 11t right up to 17t. The cranks mirror the Red design too which saves weight while the brake calipers of old Force simply get updated graphics.

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