From New York Times , Nov. 23rd , 2017 :
"Manufacturers have switched from motors attached to the hub of the rear wheel to more efficient center-drive motors in the pedal crankshaft, which improve the bike’s center of gravity and handling."
https://www.nytimes.com/2017/11/23/business/e-bikes-electric-bicycles.html
By the way , Chris Nolte , EBR forum contributor , frequent guest on EBR video reviews , and owner of Propel Bikes in Brooklyn , is also quoted in the article .
"Manufacturers have switched from motors attached to the hub of the rear wheel to more efficient center-drive motors in the pedal crankshaft, which improve the bike’s center of gravity and handling."
https://www.nytimes.com/2017/11/23/business/e-bikes-electric-bicycles.html
By the way , Chris Nolte , EBR forum contributor , frequent guest on EBR video reviews , and owner of Propel Bikes in Brooklyn , is also quoted in the article .