It's a tried and tested recipe that Specialized is already cooking up. Sram also relies on a solid motor base from Brose and runs it according to its in-house software. The motor is race-proven and has already been successfully chased through the 2022 season of the E-Enduro World Series by Sram factory rider Yannick Pontal - he won the series. Due to the racing background, Sram has kept it simple and only offers a simplified menu with just two support levels and a minimalist display. However, the system comes up trumps with the "Auto Shift" automatic shifting system, the Coast Shift, which enables gear changes without pedaling.

Two modes (have to) be enough

The system is switched on via the display in the top tube. The support modes are selected with one button on the left-hand gear pod, while the second button can be used to operate the Reverb, depending on the equipment and button assignment. It starts in Range mode, which is usually referred to as Eco mode by other e-bike motor providers. However, with a preset 50 percent of maximum power, which can be adjusted via the app, it is more than just Eco. The motor engages powerfully and very naturally and offers plenty of support even at lower pedalling frequencies, even when things get steeper or you are tackling single trail climbs.

Where more power is needed, however, on really steep ramps or to overcome steps and technically demanding terrain, you are better served with the Rallye stage. With many manufacturers, these are often called Turbo or Boost mode and are usually too brute to ride up trails in a controlled manner. Not so with the Eagle Powertrain, which kicks in gently and just as naturally as in Range mode. With increasing pressure, the motor then releases its power, but remains surprisingly easy to control even in technically demanding terrain. In addition, the motor hardly makes any drive noise at full thrust and nothing rattles downhill, which is very pleasant.

Auto-shift, yes or no?

To get the power to the rear wheel, Sram does the work for you. Depending on the gear, cadence and force applied, the GX Eagle Transmission automatically shifts up or down thanks to Auto Shift. This actually works very well. Whether downhill, straight ahead or uphill, with a more leisurely riding style, the transmission selects the right gears even on steeper and more demanding climbs.

When the chain should make the jump to the next smaller or larger sprocket can be set directly with the shift pods. At -3, the gear changes at low cadences. At +3, you have to fidget a lot until the shifting process takes place. The sensitivity can be easily adjusted on the move by pressing the downshift button for two seconds and then selecting the seven levels with upshifting or downshifting. It takes a bit of trial and error to find the right level. On this test ride, the +1 felt the best.

However, if the automatic gearshift happens too early, the system can be overridden manually for a short time. As the system cannot shift in advance, this gives you the opportunity to engage an easier gear ahead of steep ramps, which makes it easier to accelerate.

If you want to ride sportily, you won't be completely happy with Auto Shift, as it often shifts into the heavier gears too early. Either you override the system more often or switch completely to manual shifting. To do this, simply press and hold the upshift button until the display shows "Auto Shift OFF".

What cannot be switched off is the Coast Shift system, which enables both automatic and manual gear changes, even when pedaling. A freewheel in the crank makes this possible and provides a real advantage when the descent in challenging terrain immediately changes to an ascent. Even if pedaling is impossible here, the correct gear can be engaged for the counter-climb. However, these options take some getting used to.

Power until just before the end

According to Sram, the battery cells of the batteries used are currently among the most powerful on the market. For example, the 630 watt-hour battery weighs just 3.1 kilograms. During the ride test, where people often like to overdo the throttle instead of focusing on a long range, we covered around 40 kilometers and 1400 meters of altitude. That's with a rider weight of 77 kilograms and about two thirds in range mode and one third in rally mode. The range is roughly in the range of other 630 batteries and can easily be extended with a more economical driving style, but the test duration was sufficient for this.

If the battery level shows empty, it still has enough reserves to supply coupled lights and the AXS gearshift connected directly to the e-bike battery for a further two hours. However, the motor is then off. It's different when the display only shows five percent. The motor feels like it is switching off, but when you feel it more closely, you notice that it is still providing very slight assistance. This is barely noticeable, but is just enough to compensate for the additional weight of the bike so that you are not completely left hanging on the last kilometer.

Conclusion

From a pragmatic point of view, Sram's first e-mountainbike motor is not a world sensation. However, the entire system with control and shifting is really good. The Eagle Powertrain combines very powerful support with natural characteristics, while the controls are reduced to the essentials. Another plus: no matter how much it rattles, there is no freewheel clatter. The auto-shift system is currently "only" partially convincing, as it often shifts into the heavy gears a little too early when riding in a racing style. Nevertheless, it should only get better in the future and soon be the optimal solution for the majority of users. The Coast-Shift function is already a real added value.

sram.com/eagle-powertrain