That's the name we give to any part of the bike that can hurt you if you get tangled up with it when you go down. Note, we said when, not if. It's when the bike and the rider flip flop around and the various dangerous areas of the bike make contact with the rider, that serious injuries result. Just about every bike made has a huge axle nut with one of these pins dangling out. Only the rider who's been bitten by that part, normally.
Little projections stick out all over most bikes.
Many times, these darts can be covered up with duct tape, filed smoother or even slightly modified. Often, a potentially dangerous piece on a bike can be partially relocated, or adjusted out of the way. A rear brake arm that's tucked in is less likely to snag a rider than one that's dangling in the breeze. Sharp edges abound. Chain guides with square edges, square edged fender brackets, protruding tabs, angu-lar exhaust pipes, sharp edged heat shields and a thousand other items are all waiting to snare the downed biker.