Seeking to have the best center of gravity, this SRAM bicycle motor seen in the form of a patent directly integrates the battery, but should be less efficient than the “big” Eagle block.
Recognized as a manufacturer of high-end transmissions and brakes, SRAM also wants to break into motors for electric bicycles. The American brand cut its teeth on a first block called Eagle, based on an already existing model from the Brose brand. Its second e-bike motor could well be a pure SRAM product. In any case, this is what a patent, unearthed by the site, suggests PinkBike.
Two versions of the SRAM engine studied
This is still a mid-engine, but big changes are on the agenda compared to the Eagle system. Exit Brose, since the American firm is launching a new design: that of including the battery in the engine block. This previously existed on Zehus type rear motors, but never at the bottom bracket. The patent – which we were able to consult – details the motor and the space reserved for the battery, which can contain 30 cells.
The disadvantage is of course the size of the assembly, more difficult to fit on an electric bike. But the advantage of this innovation is based on a center of gravity moved towards the center and especially lower down. E-MTBs will love it.
The SRAM motor with removable battery // Source: SRAM
Here, the block integrates 40 battery cells. // Source: SRAM
The battery must be removed downwards. // Source: SRAM
We discover a second configuration of the SRAM motor, probably of greater capacity. Here, the battery extends at the top towards the downtube, and is removable. Always close to the engine, it would maintain a low center of gravity. On this version, the pack would have 40 cells. Concretely, with standard cells with a capacity of 18 Wh, the two versions offer 540 Wh and 720 Wh respectively.
An integrated charger, and ready to challenge the Bosch SX
As for the charging port, it is in development. We notice three types: classic socket, USB-C socket, or both. “This would allow the customer to only have one standard charger for their phone, computer and electric bike,” indicates the patent, in case of USB socket.
A SRAM battery motor of around 55 Nm? // Source: SRAM
A USB-C charging port is being considered. // Source: SRAM
And why not the two classic and USB-C formats? // Source: SRAM
Finally, PinkBike believes that the architecture of this motor is designed to target light e-MTBs, with a torque of between 50 and 60 Nm. This SRAM unit with integrated battery would therefore challenge the Bosch SX, but also the Fazua Ride 60 and the TQ HPR-50.
This engine, available in two versions, remains hypothetical for the moment. Indeed, a patent is not necessarily synonymous with a future launch. This technology remains no less promising, hoping to see it soon on future electric bikes.