Bafang Mid Drive Bicycle Inner Chain Guide Dog Fang

thingiverse

This is a project I designed to keep my bike chain from coming off the inside of the drive sprocket for my Bafang Mid Drive E-bike conversion. I found similar dog fang chain keepers online, but they were not long enough to reach the inside of the drive sprocket. This one extends out 2 inches from the center of the frame downtube. This keeps the chain on the drive sprocket in first gear on my e-bike. It tends to come off under low load without this in first gear. It has a upper lip to help keep the chain from rising up, and a inner lip to prevent movement towards the inside of the drive sprocket. This fits on bikes with a 32mm diameter downtube (beside the drive sprocket). It uses a #10 pan head screw and lock nut to mount on the bike. Can be modified to use screws of similar sizes.