ethirteen Helix Core e*spec DM Chainrings – Bosch CX

Helix Core e*spec Direct Mount Chainrings feature our M3 narrow-wide tooth profile, for reliable chain retention and extra long wear life. Designed with an adjustable 13.5-15.5mm offset via a spacer, they provide adaptability to both 53 and 55mm chainlines for Bosch CX motor systems. Helix Core e*spec rings are cold-formed from steel and then heat-treated to provide excellent durability and toughness, all at a price that’s easy on your wallet.