The SRAM Red eTap was mounted to a display stand for the Cape Town Cycle Tour Expo. This meant that our testing was somewhat limited but the Red eTap didn't disappoint. The demonstration rig shifted smoothly. The motors made a reassuring sound when called into action and the shifter paddles, although wireless, provided positive feedback. However, we would have to get on system on a functioning bike to make a proper assessment.
For those with existing mechanical SRAM drivetrains and an eye on upgrading, the Red eTap shares chain, cassette, cranks, and brakes with the mechanical Red groupset with only the shifters and derailleurs being eTap specific.
Instead of using cables (mechanical or electronic) to activate the derailleurs, the SRAM Red eTap sends wireless signals between the shifters and derailleurs. It was a bit strange being able to walk around (and even outside of) the room with the handlebar while shifting.
While there are a number of practical and aesthetic advantages to going wireless, there has been a big question around security and whether unscrupulous people can gain access to force a miss-shift or complete malfunction. SRAM believe they have addressed any concerns with their own proprietary wireless protocol called AIREA. AIREA uses a 128-bit encrypted signal which generates a new encryption code each time the components are paired together. Apparently they went as far as to placing security experts in team cars during races to attempt to crack the system, which they supposedly failed to do.
Despite the use of the proprietary AIREA signal, the eTap system also supports ANT+ which will allow the components to integrate happily with your bike computer and other devices.
The shifting process is a bit different. Two hands are required to shift up and down at the same time or to shift the front derailleur at all. A push of a paddle moves the rear derailleur up or down depending on which side is pressed. Holding both paddles at the same time moves the front derailleur either up or down depending on its current position. The aim of this setup is prevent any miss-shifting, which is apparently an issue with big gloves in colder climates.
Where a mechanical derailleur relies on the correct cable tension for aligned, the placement of the rear derailleur on the eTap is fine-tuned from the shifters. By pressing a shift paddle while holding the function button the derailleur will adjust itself in that direction. Each press moves the derailleur 0.2 millimetres allowing for accurate adjustment.
Unlike the Shimano Di2 grouspet, the SRAM eTap front derailleur does not need to trim to avoid chain rub. Like the mechanical version of the Red 22 groupset, if the front derailleur is correctly aligned, the entire range of gears on the cassette should be usable from either chainring without chain rub on the front derailleur cage.
As the eTap system is wireless there is no central battery pack and each component requires its own battery. The derailleurs use a custom rechargeable battery which is interchangeable between front and rear. The shifters use an off the shelf CR2032 battery which needs to be replaced when it runs flat.
SRAM say the eTap is good for 60 hours of use before needing a recharge. The battery level indicators work with a simple pressing of the function button on each component which indicates green, flashing or red depending on the battery level. A full charge of the derailleur batteries is said to take 45 minutes.
To assist with power saving, the eTap falls asleep when not in use. Accelerometers are used to detect movement, so there is no fear of the system going to sleep while being ridden.
The SRAM Red eTap also offers blips for satellite shifting on other locations on the handlebar or bike. These blips are not wireless and plug into the shifters. Unfortunately there were no blips available to try out on the test rig.
Local availability and pricing
Stock levels of the Red eTap components are currently restricted and the local distributor hopes to have some available by mid year. Pricing has not be finalised but they say that they would like to match the overseas pricing as closely as possible.