North Shore Billet Variable Tooth Chainring: 28T Standard 64 BCD Black

North Shore Billet Variable Tooth Chainring: 28T Standard 64 BCD Black. The NSB Variable Tooth Chainrings uses a Thin-Thick variable tooth thickness mated with a standard chainring tooth profile to help retain the chain on the front ring during all types of riding. By increasing the tooth thickness on half of the rings teeth the chain is given less room to move and virtually eliminates chain drop when running a single front chainring.