Siegfried's finale incorporated in the Ring Cycle (5)
I believe the answer is:
pedal
'cycle' is the definition.
(pedal can mean to cycle a bicycle)
'siegfried's finale incorporated in the ring' is the wordplay.
'finale' suggests the final letters.
'incorporated in' is an insertion indicator.
'the ring' becomes 'peal' (I've seen this before).
The final letter of 'siegfried' is 'd'.
'd' put into 'peal' is 'PEDAL'.
(Other definitions for pedal that I've seen before include "ride a cycle" , "related to feet" , "Bicycle footrest" , "sustained note" , "part of organ" .)