Freehub

A set of sprockets (called a "cassette") is mounted onto a splined shaft of the freehub to engage the chain.

The freehub concept answers several drawbacks encountered with the freewheel design: Beyond removal from the hub and of the cassette,[which?]

The outer cup covering the ratchet pawls and bearings is pressed into place at the factory, secured by interference fit, leveraging the same inner threads of the shell into which the cassette lockring normally screws.

The concept of a freehub was devised and manufactured by British company Bayliss-Wiley in 1938[1][2] and won the Cyclists Touring Club (CTC) award for that year.

Nevertheless, freewheels continue to be fitted on some new bikes, especially single speed, and cheaper models of derailleur bicycles.