Alter’s Midnight Series cogs are machined from 7075 T6 aluminum and are available in sizes 15t-19t.

FYI: All track cogs have 1.37″x24tpi threading. ALL OF THEM. Any threaded cog can be used on any threaded track hub.

specifications

standard 1.37″x24tpi threading

1/2 x 1/8″ only

15-19t

colors: purple, black

weight: 21g-38g