SRAM Red eTap is a Step Forward for Electronic Shifting
It’s here: SRAM’s wireless electronic system, in development since 2011 and publicly raced by SRAM’s professional teams for over a year, is now officially official. And though we’re excited, it’s not quite available for consumers yet. We did, however, attend a press event at SRAM’s European Development and Training Center in Schweinfurt, Germany, where the company finally provided all the info—price, weight, and on-sale details—and gave me an opportunity to ride the group.
Here’s the Brief Version
It is called Red eTap, and will be in shops in spring 2016. It shares chain, cassette, cranks, and brakes with the Red22 mechanical group; weighs 2,096 grams (about 137g more than a Red22 mechanical group when shift cables and housing are accounted for); and will cost about $2,760 for a complete group (about $780 more than Red22 mechanical).
There are accessory remote shifter buttons called Blips. The battery packs in the derailleurs are interchangeable, and are claimed to be good for 1000km or 60 hours of riding, and to be rechargeable in 45 minutes; each shift lever contains a CR2032 battery. The custom wireless communication language, called Airea, uses 128-bit rolling encryption; only one set of shifters can be paired to a system. Both derailleurs have a mechanical disconnect to prevent crash damage and protect their internals: The derailleur will give way in an impact, then returns to its original position
Why Wireless?
While electronic has more going for it than mechanical shifting—such as more intricate shift movements, remote shifters, and automatic features—wireless is just electronic without wires.
The disadvantages are easily noted: separate power sources for each element, increased complexity, battery anxiety, not to mention wireless interference anxiety.
So what, then, are the advantages? Primarily, installation and setup: There are no wires to fish through the frame, no junction boxes or batteries to place, and fewer bits to rattle. During his part of the presentation, SRAM’s advanced development manager Brian Jordan claimed it will take longer to remove a mechanical or wired electronic system than it will to install a new eTap system.
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There are less significant, but still noteworthy, advantages: no connectors to come loose or fail; no wires to accidentally cut; a cleaner looking bike; and, potentially, more opportunity for frame optimization. Those are great things, but, as Chris Zigmont, SRAM’s road brand director, noted in his launch presentation, “Once it’s set up, you don’t care if it’s wireless.”
Airea
SRAM calls their wireless technology Airea. It operates on the 2.4gHz frequency, like many wireless devices, and is not ANT+, Bluetooth, or WiFi, but a spread spectrum “custom communication language for shifting,” with, “high noise immunity,” Jordan said.
Developed by a group of programmers, cryptographers, and hackers, it employs 128bit rolling encryption and is “more secure than any cash machine,” Zigmont said, with Jordan adding that the people who developed Airea have tried to hack it and can’t.
Though the distance from rear derailleur to shifters is only about one meter, Jordan states that Airea has a range of 100 meters to ensure a robust connection. Only one set of shifters may be paired to a system.
SRAM came to its launch presentation prepared to answer every single tweet, comment, and forum post outlining cyclists’ wireless anxiety. The short version: According to Scott McLaughlin, SRAM’s global engineering and design director, the company extensively evaluated environmental wireless noise and accommodated for it by testing the heck out of Airea in the lab. Throughout nearly one million kilometers of field testing, McLaughlin said, the wireless system has been “completely flawless.”
That said, SRAM did allow that interference is possible, but not probable. SRAM also admitted that someone could potentially hack the group, but posed a rhetorical question: “Why would someone put so much effort into hacking some derailleurs? What would they get out of it?”
But let’s be real: There are people out there who may try to hack Airea just to see if they can, though shifting somebody’s derailleurs is hardly as attention-grabbing or disastrous as taking control of a passenger jet.
In addition to Airea, the rear derailleur contains an ANT+ radio for sending gear selection and battery life information to head units. SRAM says the information is sent on an open profile that any head unit maker can use. At the launch, some SRAM employees had Garmin Edge 520 head units with the profile activated.
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Battery Stuff
One of the primary differences between SRAM eTap and electronic groups from Shimano and Campagnolo is the battery situation. With a wired system, one battery powers everything, and there is one battery to keep tabs on and recharge. SRAM’s eTap has four batteries.
The front and rear derailleurs use identical lithium-polymer battery packs. SRAM had a lot of flexibility on the capacity of these packs, but ultimately the goal was enough capacity for one month of heavy use in cold temperatures “with a lot of buffer on top.” That works out to about 1000km or 60 hours of riding time for the rear derailleur; the front derailleur’s battery should last about 50 percent longer (depending on use). Those estimates are in normal conditions; below -20 and above 50 degrees Celsius, battery performance falls off.
The derailleur batteries have their own charging cradle powered by USB. The charger can be plugged into a computer, or into SRAM’s wall adapter, which can power two cradles. This is one of the advantages of SRAM’s battery packs: Unlike Shimano’s internal battery or Campagnolo’s EPS system, the bike doesn’t need to be near an outlet to charge the system. From fully depleted, they charge in about 45 minutes, and the batteries are good for about 100 charge cycles. A new or spare battery costs $40 and comes with a charge tester.
The shifters are powered by a CR2032 coin cell—the same battery found in many heart rate straps, speed and cadence sensors, and power meters. SRAM claims the shifter batteries will last about two years under normal use.
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Battery life is extended by the accelerometer in each electronic component. After 15 minutes of inactivity, the system goes to sleep; when the bike is moved, the system wakes up. When traveling longer distances or flying with the bike, SRAM recommends removing the batteries because the constant motion will prevent the system from sleeping. If a shifter button is pressed for 15 seconds or more, the system sleeps.
Current charge status is indicated by an LED on each component. A green flash indicates 100 to 15 hours of use left; a single red flash means 15 to five hours left; five quick red flashes and less than five hours remain.
Shifting
Like SRAM’s mechanical groups, eTap uses a one lever (button)—one direction format, but takes advantage of the capabilities of electronics to initiate shifts in a way mechanical can’t.
SRAM describes eTap’s shifting as similar to a sports car’s paddle shifters: Press the left side paddle for rear derailleur downshifts (easier); right side for rear derailleur upshifts (harder). Hold a button down and the rear derailleur will continue shifting until the button is released or the largest/smallest cog is reached. For a front derailleur shift (up or down depending on start position), press left and right buttons at the same time.
This format, Zigmont said, makes it “impossible to mistake upshift for downshift, and impossible to accidentally execute a front derailleur shift.”
Electronic shifting offers many more possibilities for shift button placement than mechanical, and SRAM did explore and test many different layouts, McLaughlin said. But it returned to its signature shift paddle movement, placement, and shape because internal feedback deemed it most advantageous. McLaughlin did allow that because it was mostly SRAM employees testing the different button placements, their familiarity and comfort with SRAM’s mechanical ergonomics may have resulted in the final outcome of eTap’s ergonomics.
The front derailleur borrows Yaw cage articulation from the Red mechanical group. Yaw, claims Brad Menna, SRAM’s road project manager, eliminates front-derailleur rub without resorting to automatic trimming, like Campagnolo and Shimano’s electronic groups, as the rider works up and down the cassette. The initial movement of the eTap front derailleur does vary depending on the rear cog selected.
Each shift lever has ports for remote shifter buttons called Blips. Blips shift the same direction as the shifter they’re plugged into, and can be used together to shift the front derailleur —provided one is plugged into the right and one is plugged into the left. Two Blips can be plugged into each shifter, so the shift levers with a full complement of Blips would offer three locations per side from which to shift. Four different wire lengths (150mm: 6 grams; 230mm: 7g; 450mm: 8g; and 650mm: 9g) allow them to be placed almost anywhere on the bar.
SRAM showed many different examples of placement, including positioning two directly next to each other so all shifting could be done from the bar tops with one hand. Blips can be exposed, mounted under bar tape, or glued directly to the bar.
Shifting speed and direction is not customizable and there are no diagnostic tools available. However, a USB transmitter and software (for both Windows and OSX) will be offered to push firmware updates. Lever reach is adjustable.
eTap for Triathlon and Time Trial
Wireless is particularly advantageous for ever-more complex and integrated time trial and triathlon bikes, and SRAM will offer eTap for aerobar setups from the start. The solution is based around the Blips described above, but instead of plugging into the drop bar shift/brake levers, they plug into a Blipbox sending unit (31 grams, $300, powered by one CR2032 battery). The four-port Blipbox (two buttons per direction) is a hair smaller than a Garmin Edge 500, and mounts to the bike with a quarter-turn Garmin-style interface.
Setup
The shortest part of SRAM’s eTap launch presentation was the derailleur mounting and pairing, and fine-tuning the shifting.
The front derailleur is installed and set up like SRAM’s Yaw mechanical front derailleur but with two tweaks: It uses a reinforcing wedge (three are included to accommodate different frame shapes) to prevent the derailleur from flexing while shifting, but does not use SRAM’s chain spotter. A press of the function button on the front derailleur shifts the derailleur inboard and outboard so it can be set up without pairing the shifters. The rear derailleur (28-tooth max) is bolted to the frame like any rear derailleur.
Pairing is faster and simpler than pairing a Bluetooth headset to a smartphone. For a demonstration, check out this one minute video.
Fine-tuning the rear derailleur shifting is achieved by holding the function button on a shift lever while pressing the lever: The left button moves the derailleur left, while the right moves it right. Each press moves the rear derailleur 0.2mm, and there are a total of 26 positions, enough range for a complete shift.
Testing and Manufacturing
In addition to testing the wireless robustness, SRAM implemented other tests for its foray into electronic shifting. Most significantly, every shifter and derailleur is powered up and tested at the end of the production line.
But before the parts got there, McLaughlin said, SRAM did other testing during the development of eTap to ensure the electronics were dust- and waterproofed and could stand up to “aggressive power washing”.
Additionally, SRAM tested eTap for plenty of other possible stumbling blocks: chemical compatibility and corrosion resistance, to ensure common cycling lubes and cleaners don’t harm the products; temperature (both extremes and rapid temperature changes) and humidity tests; static discharge resistance; various tests to prove the security of the battery attachment and to ensure it can’t be improperly installed; and vibration and tumble testing.
Though the circuit boards are manufactured out-of-house, the eTap shifters and derailleurs are assembled at SRAM’s factory inside a clean room, by workers with anti-static protection.
An interesting anecdote about eTap’s SRAM’s production history: The company tooled up a full production line for its third generation of prototypes for training and learning only. At the end of the run, all the parts were destroyed, and the line was torn down and then rebuilt for final production using the knowledge gained in the mock run. By the time eTap reaches final production, SRAM will have spent five years developing the manufacturing process and will have completed 32 pilot runs on eTap.
Riding eTAP
I was able to ride eTAP for 233km over eight hours at this press event. While not a long-term test, it is more time than I usually get on a product at a launch.
Here’s what struck me the most: The group’s most notable feature–being wireless–is not noticeable while riding. Within a few kilometers, the wireless part is forgotten because eTAP behaves like an electronic group. There is no lag, no misfires: Push the button and it shifts, just like any wired electronic or mechanical group that’s been properly set up.
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There were no interference issues. Our group numbered close to 50—we were together for initial setup and bike fit loops in the parking lot, and then broke into two groups for our ride— all equipped with eTAP, all carrying wireless phones, most using Garmin head units, many equipped with power meters. Our rides began in an industrial city with lots of people, wireless communications, power lines, and other potential sources of interference—and there were no glitches. I would guess that it is possible to encounter some interference somewhere, somehow, that may hamper a shift. But it’s possible only because it’s not impossible. Based on my initial rides, I will have no “wireless anxiety” when I ride eTAP in the future.
SRAM’s mechanical ergonomics work well for me, so adapting to the eTap hoods and levers was easy. Like Shimano Di2 vs. Shimano mechanical, the eTap hoods are slightly smaller in diameter than their mechanical counterparts. Blessed with comically-short fingers, this suited me well, and I took full advantage of the provided reach adjustment.
Shifting was intuitive and, other than brain-farting and trying to use the right eTap lever like a SRAM mechanical shifter a few times, I never missed a shift I wanted to make. The front derailleur shifting action was easy to adopt, and there seems to be some forgiveness in the system so you don’t need to be extraordinarily precise with the timing of the lever presses. By my third ride on the group, I did find there was truth to SRAM’s statement that you can’t mis-shift this system.
Guessing that I was going to ride eTap at this event, I spent my rides preceding the launch exclusively on Shimano Di2 and Campagnolo EPS. In comparison, eTap’s rear shifting felt a little slower and noisier than both, and somewhat less smooth than Di2 (though the eTap was brand new and the Di2 and EPS were well broken-in).
I asked SRAM representatives about the shifting speed and they said they had wide latitude in this area, but settled on the final speed based on testing and feedback from field testers and professional athletes. They wanted it fast enough to feel responsive, but not so fast that it jumped or skipped the shift gates.
It’s hard for me to say if I would prefer it faster or not (I’d need to try different speeds to find out), but I don’t think the shifting speed, though slower than anticipated, was detrimental to my experience or ride performance. Perhaps it was just that I had a certain expectation, not right or wrong, and it was not met.
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The brake calipers are the same as those in the current Red mechanical group, and braking performance felt the same: Good, though our rides were rolling affairs on open roads in good weather with nary a switchback or grade exceeding a few percent. (I rode the latest Zipp carbon wheels with Zipp platinum pads.)
Where it Goes From Here
SRAM has a number of products that could see wireless enhancement. SRAM representatives were not exactly subtle with their hints about eTap’s next step: Hydraulic braking for rim and disc. I’d also expect to see a 1x-specific rear derailleur—with straight parallelogram and clutch—in the not too distant future. Hydro plus 1x would make for some seriously happy cyclocrossers. No mentions were made of eTap for mountain bikes, but I can say with some certainty that it is on the to-do list.
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