SRAM Powertrain: automatic shifting comes to SRAM with a total eMTB system

SRAM has introduced a system to fully integrate its Eagle Transmission into electric MTBs. The Eagle Powertrain features a 90 NM Brose motor with two modes of assistance, 630 Wh or 720 Wh battery and an exclusive automatic shifter. It also stands out for its high degree of customization with the AXS application and compatibility with other systems.

SRAM Eagle Powertrain: the leap to e-MTB becomes a reality with an all-round system

SRAM is back with an announcement that promises to shake up the cycling scene once again. If at the beginning of the year Eagle Transmission marked a before and after by eliminating the derailleur hanger and proposing other ingenious innovations, in the summer came the GX version. Now, the American giant has decided to bite into the electric part of the MTB pie with this new release.

Eagle Powertrain is a complete eMTB drivetrain system that integrates the Eagle Transmission to take complete control of an eMTB. In addition, it does so with a new automatic transmission system that allows you to shift gears without pedaling.

Keys to SRAM Eagle Powertrain

Before going in depth, let's see what are the most important features of this system.

• The SRAM Eagle Powertrain is a complete eMTB drivetrain system (motor, battery, shifting system, controls and the drivetrain itself).
• Auto Shift: exclusive automatic shifting
• Coast Shift: rider can shift without pedaling
• AXS Bridge Display and four buttons to control the entire system
• Brose motor with 90 Nm and 680 W maximum power
• Two customizable assistance modes: Range - longer rides, less power - and Rally - maximum power
• 630 Wh or 720 Wh battery. Possibility of incorporating a 250 Wh range extender.
• Rockshox Reverb AXS dropper post
• Compatible with Eagle Transmission and GX Eagle Transmission. Also compatible with mechanical or Eagle AXS transmissions, but without Auto Shift and Coast Shift functions.

SRAM Eagle Powertrain, a new twist to conquer e-MTBs

Eagle Powertrain is the sum of several SRAM technologies, which have resulted in a system that fits the needs of e-MTBs. First of all, it incorporates Eagle Transmission, so, logically, it shares its best-known features; that is, it dispenses with derailleur hanger, cables and front derailleur.

SRAM explains that the motor delivers just the right amount of power so that pedaling occurs organically. The development of Eagle Powertrain has been carried out together with professional cyclists, who have been testing this system for two years.

Automatic and without pedaling: cutting-edge shifting technology

One of Eagle Powertrain's strengths is the Auto Shift and Coast Shift technologies.

The first of these refers to the automatic shifting, something that the brand only offers in this system. SRAM wants the rider to forget about the drivetrain and only think about the handling of the bike. The automatic shifting detects the pedaling commands and acts accordingly to fulfill the rider's wishes.

The cyclist can override the system, although the brand indicates that when it is activated, the motor is more efficient, as it maintains a constant and comfortable cadence, as well as using less energy when starting from a standstill.

Automatic shifting can be customized to suit individual style and cadence preferences.

Electrical and software engineers Dominique Fuss and Victor Freyssinet call it "the sixth sense of a bike, deciding when to shift gears so riders can concentrate on riding. It's not just smart technology, it's the ultimate riding companion."

Coast Shift allows shifting without pedaling as long as the bike rolls by inertia. The technology gives the crankset the ability to move independently of the cranks. This offers the advantage of shifting at times when pedaling becomes difficult, such as on uneven terrain, downhill or in low-speed areas.

Electric assistance: 90 Nm motor and 630 Wh or 720 Wh batteries

The drive unit is a 90 Nm, 680 W Brose that is quiet and offers a natural pedal feel, according to the brand.

Unlike other engines, in this case there are two assistance modes. The Range mode reduces power - indicated for long rides, with easier terrain or when power must be conserved - while the Rally mode provides maximum power. In addition, both can be customized from the AXS application.

SRAM has used "heat-resistant materials that provide superior thermal performance - they claim it has the best heat-to-power loss ratio in its class - and allow for longer power delivery."

Finally, it also has the Push function, which allows the rider to push the bike on difficult terrain - or even on stairs - thanks to the motor assistance of up to 6 km/h.

The 630 Wh or 720 Wh battery can be removed with a single Allen key and can be reinforced with a 250 Wh extender. The system discharges the extender in Range mode and the main battery in Rally mode. We compare the two battery options in the table below.

Battery	Features	Weight	Charging times
630 Wh	Compact size, sportive, low center of gravity	3 kg	4,5 hours.
720 Wh	Full size, maximum range	4.1 kg	5 hours

One display and four buttons to rule them all

The AXS Bridge Display is intuitive, bright, colorful, waterproof and the "nerve center" of the entire system. SRAM's goal has been to simplify the bike control experience; an extension of the bike that is one of the gateways for the rider to govern their machine at will.

The display can be used to turn the motor on or off, switch between Range and Rally modes, and log in or log out.

The other way to give orders to our bike is through the POD buttons; four in total, two on each side. With them you can switch between Range and Rally modes of the motor or control the dropper post, among other functions.

Highly compatible and customizable system

Eagle Powertrain is compatible with any Eagle Transmission -XX SL, XX, X0 and GX-. In addition, it is also compatible with mechanical or Eagle AXS transmissions, although in these cases they will not have the Auto Shift and Coast Shift functions if they do not mount a Transmission groupset.

The AXS app is all about enriching the experience once the rider is off the bike. The app allows customizing the starting power, Range and Rally modes of the motor, checking the battery life from outside the bike and adjusting various parameters, among other resources, with the cell phone.

SRAM Powertrain: availability and price

SRAM reports that Eagle Powertrain is a manufacturer-specific system, which means that it will come standard on some models and will not be sold separately, so we don't know anything about pricing at this time.

It also indicates that it will initially be available on some models of the Propain, Nukeproof, Transition and GasGas Bicycles brands, although it expects to add more partners in the near future.