From road bike to MTB
Shimano, Sram and Campagnolo all offer electronic drivetrains for road bikes. Electric gears have been on the rise for years and are almost standard from a certain price range upwards. For mountain bikes, there have so far only been the two Di2 groupsets from Shimano (XTR Di2 and XT Di2), which, however, did not manage without wired components. Under the abbreviation AXS (Access: access/connection) bundles
Sram all future electronic products and brings the technology of road bike wireless shifting to the off-road.
Sram AXS: two new wireless drivetrains
In the MTB sector, Sram is launching two 1x12-based groupsets: XX1 and X01 Eagle AXS. In addition, there will be a Reverb AXS telescopic seatpost, which is also wirelessly controlled and thus implements the rider's commands. There will be no need for tedious routing of Bowden cables or even hydraulic lines, including shortening and bleeding. A tidy appearance is also included. The rattling of cables inside the frame is also a thing of the past, as is readjusting the gears because the outer casing has settled or is sluggish due to dirt.
600 euros more expensive than mechanical 1x12 groupsets
Apart from the shift lever or controller and the rear derailleur, the remaining parts such as the chain, cassette and crank are identical to the previous mechanical groupsets from Sram. At 2100 and 2000 euros respectively for the complete groupsets, the price is around 600 euros higher than the previous top Eagle drivetrains from Sram. In terms of weight, the new AXS groupsets should even be minimally lighter. Sram puts the battery life at 20 hours of riding time for the rear derailleur and the button cell installed in the controller should last for over two years. For comparison: On a racing bike, you can manage around 16,000 shifting operations with one eTap battery charge. The quickly replaceable battery, which weighs just 25 grams, can be fully charged within an hour. The battery is identical in construction to the battery of the eTap road bike shifting group.
The subject of durability
To ensure high reliability, all components are waterproof and dustproof. The parts should also withstand washing with a high-pressure cleaner, even if Sram advises against it. To better protect the AXS rear derailleur in the event of a fall or contact with a stone, it has an overload clutch. In the event of an impact, the parallelogram can move inwards and then automatically returns to its original position.
Personalise and read out
An app for personalising and reading out the Sram AXS electric drivetrain is also available. This allows the rider to see not only how long they have been riding, but also how often they have shifted gears and which gears have been used most frequently, which can help to optimise the gear ratio. In future, the app will also indicate when the chain should be oiled or replaced. The app can also be used to personalise the controller.
Facts about the Sram AXS MTB drivetrains at a glance:
- XX1 Eagle AXS - Price: 2100 Euro / X01 Eagle AXS - Price: 2000 Euro
- same weight as the mechanical Eagle groupsets
- Battery life 20 hours rear derailleur / two years controller
- Available from April 2019
Rock Shox Reverb AXS
Not only the circuit, but also the Reverb lowerable seat post receives a wireless update. The new Reverb does not require a hydraulic remote control, thus eliminating the need for time-consuming installation with line shortening and bleeding. In terms of operating logic, the AXS version of the Reverb seatpost as before. As long as the button is pressed, the height of the support can be adjusted. When you release the button, it is fixed again. This is done intuitively, quickly and with very little effort.
E-shift and Reverb AXS in combination
If you also use the AXS circuit, you can customise the assignment of the buttons via the app, for example by assigning them to the right-hand side. In addition to wireless control, other details have been improved. The new "Vent-Valve", with which the reverb can be vented quickly at the touch of a button, which eliminates the frequent drop. Friction has also been reduced thanks to an optimised separating piston and a better lubricant. The new Reverb clamp head, which accepts round and oval saddle rails, makes it easier to adjust the saddle angle. The price is 800 euros.
Facts at a glance:
- Reverb AXS - 800 euros (57 grams heavier than the hydraulic version)
- 30.9/31.6/34.9 mm available
- 100-170 mm lowering
- Extension speed can no longer be adjusted
- Battery life 40-60 hours
- Vent-Valve quick venting
- Available from February 2019
Further information on the AXS components from Sram with a first ride report and a comparison with the Shimano Di2 can be found in BIKE 4/19 - on newsstands from 5 March!
