Bar plugs or stop caps: plugs with the finishes of handlebars that avert the bare tubing from stabbing you in a very crash and that hold handlebar tape in place. Hanger: part of frame or an attachment into the frame to which the derailleur is hooked up (see Derailleur hanger) https://bikeenginetypes72580.get-blogging.com/35558044/a-review-of-bike-engines-explained