It's been rumoured for years now but SRAM has finally introduced its Eagle Powertrain e-MTB drive system. First, SRAM dropped the front mech with its Eagle drivetrains, then cables with AXS and then the mech hanger with Transmission – all of which have led to this moment. Eagle Powertrain utilises all of those technologies to offer the most natural e-MTB experience to date.
Compared to the likes of Fazua, Bosch and Shimano, SRAM is late to the e-MTB drive system game but that means that the brand can take note of what already exists and improve on it.
SRAM has developed its own motor in partnership with Brose which it reckons offers the most natural pedalling experience. It gets unique-to-SRAM software and a punchy 90Nm of torque and 680W of peak power. The brand also reckons that it comes with the best-in-class derating (or heat build-up vs power loss).
That motor is powered by full-size batteries with 630Wh (offering 4.5 hours of usage) or 720Wh (five hours) capacities, each of which can be removed using a single Allen key. The former battery offers a low centre of gravity and weight a claimed 3kg whereas the larger battery comes in at 4.1kg. The battery has been shaped in order to streamline the interface between the battery and drive unit. As a result, it's said to deliver more power in a smaller area, thus offering a slimmer form and hopefully, nicer-looking e-bikes.
Instead of throwing in all of the support modes, SRAM has opted for just two with the aim of keeping things simple. Range Mode does what it says on the tin, offering better range for longer routes, or while riding easier terrain. It's all about conserving power. Rally mode outputs all of the power. Each mode can be customised, however, using the AXS app.
Taking a leaf out of Shimano's book, Eagle Powertrain comes with very clever Auto Shift tech. This takes away all of the thinking behind shifting as it senses rider input and shifts accordingly. But this can be easily overridden, accepting rider commands as and when, and it can be tuned to the rider's preference.
This tech also allows the rider to Coast Shift by allowing the chainring to move independently from the cranks. As such, a rider can change gears without having to pedal.
Shifting, dropper actuation and mode swapping are all done through SRAM's Pod shifters that we saw upon the release of Eagle Transmission. These serve as familiar contact points for those who are already well acquainted.
Finally, Eagle Powertrain is monitored through the use of the Eagle Powertrain AXS Bridge Display, which is a control unit that mounts to a bike's top tube. It's waterproof, full colour and protected under Gorilla Glass. This is where you'll find all of your ride info, switch between Range and Rally modes as well as enter the service mode. Of course, this is also home to the power button.
2023 specialized s works levo gen 2 pod.jpg, by Liam Mercer
SRAM Eagle Powertrain is a complete system that's specific to bike manufacturers and, at the moment, it can be found on Propain, Transition, GasGas and Nukeproof e-MTBs. There's also a handy range extender available.
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