We recently converted our road bikes to e-Bikes, installing a Swytch conversion kit – a hub motor and lightweight battery. We can still ride the bikes as ‘regular’ pedal bikes, but have the option to flick a switch to fire up the battery for that long climb.
Most importantly, we have only added 3.5kg to each bike, so that they can still be carried on our rear door-mounted rack, without exceeding the rack load limit.