Wolf Tooth Shimano EP-8 Direct Mount Chainring - Drop-Stop ST 32T Black. Wolf Tooth Direct Mount Chainrings for Shimano EP-8 E-Bike Motors are compatible with all Boost and Super Boost bikes that use the Shimano EP-8 Motor. This brings a lightweight chainring with patented Drop-Stop® technology to e-bike chainrings for the first time. Direct Mount Chainrings for Shimano EP-8 E-Bike Motors are machined with 7075-T6 aluminum at Wolf Tooth in Minnesota USA.