Shimano had this back in the 80's...called it '[Front Freewheel System](https://www.google.com/search?q=old+schwinn+freewheel+crank++drivetrain&tbm=isch&imgil=TyyNzu9WzKvgHM%253A%253BXgUXb9sW_ERvOM%253Bhttp%25253A%25252F%25252Fwww.ebay.com%25252Fbhp%25252Fschwinn-freewheel&source=iu&pf=m&fir=TyyNzu9WzKvgHM%253A%252CXgUXb9sW_ERvOM%252C_&usg=__dDE0lqPC66pNsLqMW8xCI5KxoaI%3D&biw=1920&bih=950&ved=0ahUKEwjG27KQiMPUAhUR32MKHWCaC5UQyjcINg&ei=oixEWcaCB5G-jwPgtK6oCQ#tbm=isch&q=shimano+front+freewheel+crank&imgrc=Q5ppdyVain-EyM:)'. Besides reducing sprung weight, it allows you to shift gears while coasting.
June 16, 2017, 12:13 p.m. - Gregg Rouse
Shimano had this back in the 80's...called it '[Front Freewheel System](https://www.google.com/search?q=old+schwinn+freewheel+crank++drivetrain&tbm=isch&imgil=TyyNzu9WzKvgHM%253A%253BXgUXb9sW_ERvOM%253Bhttp%25253A%25252F%25252Fwww.ebay.com%25252Fbhp%25252Fschwinn-freewheel&source=iu&pf=m&fir=TyyNzu9WzKvgHM%253A%252CXgUXb9sW_ERvOM%252C_&usg=__dDE0lqPC66pNsLqMW8xCI5KxoaI%3D&biw=1920&bih=950&ved=0ahUKEwjG27KQiMPUAhUR32MKHWCaC5UQyjcINg&ei=oixEWcaCB5G-jwPgtK6oCQ#tbm=isch&q=shimano+front+freewheel+crank&imgrc=Q5ppdyVain-EyM:)'. Besides reducing sprung weight, it allows you to shift gears while coasting.