Front-wheel drive is the cheapest (and the engines are usually quieter than the average engine).
With “regular” e-bikes you have at least the following distribution:
* Front wheel drive: cheap, relatively quiet, simpler (and the bottom bracket can be completely “normal”, with just a spin sensor or torque sensor.
*Middle Drive: It feels “more natural” because you’re supported in the part of the bike where you put your “power” as well. And I always think with a torque sensor (at least with well-known brand A systems like Shimano Steps, or Bosch systems).
* Rear wheel drive: As far as I know you mainly see this on really sporty bikes or really holiday bikes. I don’t think you have many options in terms of gearing (and if you want you’re already stuck with a derailleur). Some bikes with rear wheel motors can also brake and regenerate the engine, for example in the mountains.
My girlfriend’s previous electric bike was a Gazelle with a front wheel drive, rotation sensor and 7-speed Nexus hub. This was really just a modest thing (even if it already cost enough). In dry conditions on regular asphalt, it was comfortable, but on surfaces with sand or gravel, it was particularly annoying for the front wheel to slip because the engine power to the front wheel was completely out of sync with the self-generated power on a ‘traditional’ transmission system.
It now has a Patavos with a Bosch Active center-mounted engine and an 8-speed Nexus gear. This makes a huge difference in terms of ride comfort and a natural feeling of support.
By the way, we also have a two-wheeled electric cargo bike (from bakfiets.nl) with a Shimano Steps mid-drive. It also goes great, especially with our daughter in it and some luggage and then up the hill.
But the story is long: The front wheel drive is used by nearly every e-bike manufacturer who wants to keep the bike cheap, at least in the electric drive field.
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