Hayes mount adaptor front post to ishayes mount adaptor to mount a 74mm post mount caliper i e hayes avid etc to a 51mm international standard fork mount i e rockshox marzocchi etc seperate mounts are available for forks with either a qr axle or a bolt through 20mm axle please note quick release axle forks require the thinner qr adaptor option 20mm bolt through forks use a thicker mount buy hayes components from chain reaction cycles the worlds largest online bike store