SRAM's electric-assist bicycle motor is launched

SRAM has finally announced the launch of its e-assist bike motor, called the Eagle Powertrain.

It was developed in partnership with Brose and is primarily designed for eMTB use, in conjunction with their AXS wireless technology and Eagle Transmission. What is worth looking forward to is that the new feature of Eagle Powertrain is the addition of automatic transmission function.

Given that SRAM acquired German brand Amprio earlier this year, the collaboration with Brose is even more interesting.

SRAM and Brose have assembled a powerful 90Nm motor that delivers 680W of peak power. To simplify the process, SRAM chose to use only two assist modes: Range Mode, which does what it recommends and works best on easier terrain to manage battery drain. Then there's Power mode, which is more of a boost mode, perfect for big climbs and tough technical features. Both modes can be customized through the AXS app.

There are two battery sizes available: 630Wh, which provides up to 4.5 hours of use, and 720Wh, which provides up to 5 hours of use. For a more secure design, the battery is secured using hex screws, which alleviates concerns about the removable battery detaching from its mount in turbulent terrain.

The interface between the drive unit and the battery has been simplified, which means we may have a chance to see some truly minimalist eMTBs, with the design keeping components in a cleaner position on the vehicle.

Perhaps the most exciting aspect of the Eagle's powertrain is the use of automatic shifting technology. This essentially lets the bike determine gear changes and power delivery based on terrain and cadence. It relies on powertrain software to select the appropriate gear, but can be overridden by the rider, much like canceling cruise control in a car by activating the necessary pedals.

Automatic shifting technology also includes coasting shifting, which allows the chainrings to move independently of the crank. This means the rider can shift gears while stationary. It also records the current bike speed to select the most appropriate gear. SRAM’s Pod shifters may seem a bit strange to riders unfamiliar with the system, which controls automatic shifting, manual shifting, and dropper use.

In addition to the auto-shifting technology, the Eagle Powertrain syncs with derailleur gears and some RockShox components, including the Flight attendant fork and shock and the Reverb AXS seatpost.