>>1601404my opinion of mid-drive kits including my steps motor is they all eat chains and cassettes for breakfast. MTB chains cannot simply handle the power. I get about 1200km before a cook a chain and the lowest 2 cogs on my 250watt eeb. and it gets worse the higher your power. Its really not economical.
In regards to motors the name brands have better torque sensing and seals on the bearings. Its an interesting space thothe chinks are catching up , Bafang has just released a 90nm torque motor that is meant to drop into the standard shimano ebike mount.
Also prebuilt is the way to go but there is simply no stock at the moment, we have customers waiting till sept to buy a new merida e-one sixty so DIY might be some peoples only choice
