Ego-Kits E-Powered bike does the job for you

The electric powered mountain bike offers enough power to help you easily climb up a mountain trail. It includes a battery pack, crankset, chain, throttle, and charger to ensure it lasts your whole ride.

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In addition, the engine can be attached to 70% of commercially available downhill bikes.

There are no official news regarding prices or availability.

Source: Ego-Kits via BeSportier via UberGizmo via Gizmodo