Track cogs are designed to spin onto standard ISO-threaded (1.375" x 24tpi) hubs, so they will work with most English, Italian & Japanese hubs, including the Surly New track hubs. The thread base is 7.4mm wide for maximum thread engagement while maintaining enough room for a track lockring to thread on. Like our cassette-splined cogs, these are made from machined, heat-treated & chrome plated SCM415 Cro Moly steel, so they are tough & long lasting. Track cogs are available in either 3/32" or 1/8" tooth thicknesses & in every size from 13-22t.