Sram’s eTap shifting simply had to be impeccable. Sram was in the crosshairs of every sceptic who wished to shoot down the wireless shifting concept, waiting to pounce on any tiny glitch.
But the glitches didn’t come. No one’s gears started going haywire as they rode near a mobile phone mast. No one had their gears hacked. Shifting was solid and reliable, even in pouring rain, covered in muck and filth on a winter ride. Sram had delivered a superb product.
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I’ve used eTap for months now – see page 2 for a full review – and can hardly fault its performance, which is why I was keen to find out how it would be affected by the addition of hydraulic disc brakes.
On paper, eTap HRD should be a simple marriage of Sram’s already proven Red HRD (Hydraulic Road Disc) callipers to the eTap shift levers.
With much less internal gubbins in the eTap lever body compared to the mechanical version, it appeared Sram’s engineers had a straightforward task ahead. But nothing is ever that easy.
Starting from scratch
‘eTap HRD (Hydraulic Road Disc) is an all-new design. It’s not like the Red HRD at all,’ says James Alberts, Sram’s brake product manager.
‘The calliper has a lot of new features to do with pad clearance and heat management but also ease of set-up and servicing. We’ve worked really hard on the controllability of the braking.
‘You don’t want a brake that hits you with all its power at once. You want feel, so you can control it.
‘For that we had to work a lot on the piston ratios – the size of the piston at the lever, the rate it pushes fluid through the system, to the size of the piston at the calliper and how much it moves the pads.’
Before I could test Alberts’ claims, I had to attach the system to a bike, which was much easier than I thought it might be.
The hose-cutting, hydraulic connections and bleeding were all simple processes. Sram calls it Bleeding Edge Technology, meaning the internal architecture has been altered to change the way the fluid flows in order to reduce the chance of trapped air.
It’s still not quite as slick as Shimano in that department, but it’s a big improvement over Sram’s previous convoluted methods.
Setting off on a ride, I immediate noted how similar the eTap HRD levers felt to the mechanical versions. The eTap HRD hood is 4mm larger, but I struggled to notice.
The slim design felt good in my hand and it’s visually a big improvement over the original Red HRD hood shape.
Also pleasing was the lack of pad rub when riding hard out of the saddle – the bane of so many disc bikes.
Sram claims a pad clearance of 0.4mm each side, which doesn’t sound much but during set-up there’s daylight between the pad and rotor, so as long the hub and axle hold the rotor firmly in place, you can ride in silence.
The size of the rotor affects both the available braking force and its ability to dissipate heat. Sram recommends a 160mm rotor, but after just a short period of testing I opted to flout its advice and switch to a neater 140mm.
In terms of performance the HRD levers delivered just as promised. The braking force comes in a progressive manner.
Initially slow to react (a good thing), the modulation through the middle of the lever stroke is well regulated before ramping up to a force that’s well beyond anything my 67kg bodyweight requires.
Boiling point
Heat management is a big concern for disc brakes. The eTap HRD callipers have a number of specific features designed to reduce heat build-up. Alberts assures me these callipers run cooler than anything in the past.
‘The calliper has a wider opening to increase airflow for improved cooling.
The aluminium pistons are thermally insulated and there’s a stainless steel heat shield that sits between the brake pad and the calliper body, both of which reduce the heat transferring to the fluid, reducing its temperature by 35°C in lab tests.’
With other hydraulic set-ups (including Sram’s Red HRD) I found that if I dragged the brakes on a long descent it was possible to get enough heat in the system that the brakes would rub for a while as the fluid expansion pushes the pads closer to the rotor.
I couldn’t induce the same effect on the eTap HRDs, which suggests the claims about improved heat management are true.
Combined with wireless shifting, the flat mount eTap HRD calliper and 140mm rotor combo on this Cannondale Super Six Evo is the neatest and cleanest solution for a road bike I’ve seen to date.
The next step will be to get rid of the brake hoses too for the ultimate clutter-free bike. I’m not sure how they’re going to manage that, but I’m sure Sram is working on it.
The spec
Sram groupset weights
Red eTap HRD components 960g
Red HRD components 958g
Red eTap (rim brake) 675g
Price (Sram Red eTap HRD) £2,387
Contact
Sram Red eTap groupset review
21 March 2016
It was only with the advent of Di2 in 2009 that Shimano finally persuaded the cycling public to adopt electronic gear shifting. Since then, Di2 has enjoyed such success that there is now talk of it filtering down to the mid-level 105 groupset.
Campagnolo followed suit with the launch of its EPS electronic system in 2012, which rather left the other big name in groupsets, Sram, out in the cold.
But the American company has at last released its much-anticipated eTap Wireless system, and the question has to be asked: was it worth the wait?
On the pulse
Realising the industry didn’t really need a ‘me too’, Sram set about upping the ante by going wireless. This immediately threw up a number of potential problems.
What if the signal between shifter and derailleur gets interrupted? Could it be ‘hacked’ by rivals? Could multiple bikes running the same system interfere with each other? Would phone signals cause problems?
I am firmly convinced Sram’s new system is not only problem-free but is potentially the new benchmark for all electronic groupsets to come.
Having suffered the financial and reputational consequences of a recall on its hydraulic brake systems in 2013, Sram knew it couldn’t afford to get this one wrong, and so it went to extreme lengths to ensure everything worked flawlessly on the new eTap groupset.
It will be a while before we can categorically say it has succeeded, but at the time of writing I am firmly convinced Sram’s new system is not only problem-free but is potentially the new benchmark for all electronic groupsets to come.
I was fortunate enough to be at the official launch of Sram eTap in Schweinfurt, Germany, late last summer, and was immediately impressed by how easy it was to set up.
It took all of five minutes to take the parts from their box, attach them to the bike and complete the wireless ‘pairing’ procedure, where normally I’d still be grappling with cable cutters as the sun goes down.
I’m also sure most mechanics will be overjoyed that this system negates the need to feed cables through tiny holes in bike frames.
All that’s required is to bolt on the four individual parts – two shift levers, front derailleur and rear derailleur – and ‘pair’ them with the push of a button on the rear mech, followed by a single press of the individual buttons on each component.
Setting the limit screws on the mechs was mildly more complex, but straightforward enough for most people to grasp. Fitting them was easy-peasy.
Wireless technology requires that each component has its own power source, unlike the single battery used by Shimano and Campagnolo, but this actually brings a number of benefits.
Firstly, there’s no hiding lumpy batteries inside seatposts or frame tubes. The batteries in the eTap shift levers are simple coin cells that are available in any supermarket, with an expected lifespan of around two years.
The mechs use clip-on lithium polymer rechargeable batteries that are small and light. The life expectancy of these is about 1,000km or 60 hours of use.
The mech batteries are also interchangeable, so in the event that your rear one runs flat, you can switch it with the front mech battery to get you home. Being removable also means you don’t need to park your bike next to a power source to charge them up.
Slick and precise
Intuitively the right-hand lever button shifts the rear mech down the cassette; the left shifts it up; press them together to switch chainrings.
I was amazed at how quickly I got used to the system, and the shifting was precise. During testing it never missed a beat, even when it was covered in muck, on a magnetic resistance turbo, close to phone masts, or any other situation where it might be found wanting.
Personally I’d like the shift speed to be a smidgen faster, especially during multiple down shifts. Arguably most riders would never even question it, but in direct comparison to Shimano’s Di2, eTap’s shift response just feels a fraction slower. Perhaps an optional firmware update could be offered to allow riders to fine tune this aspect.
Also, with the eTap I needed to ease off the pedal pressure to ensure smooth front shifting more so than with Di2. But again, it’s only marginal.
Overall, what Sram has achieved with eTap is highly impressive, especially as it has resisted the temptation to give it a sky-high pricetag. Once frame manufacturers get on board, I don’t think it will be too long before we see wireless-specific frames, which will remove the need for holes or cable ports that ruin looks and compromise tube strength.
The eTap represents a real step forward, and it will be interesting to see how Sram’s big rivals respond.
