Plead to change bicycle part (5)
I believe the answer is:
pedal
'bicycle part' is the definition.
('pedal' is part of 'bicycle')
'plead to change' is the wordplay.
'to change' indicates anagramming the letters.
'plead' is an anagram of 'PEDAL'.
(Other definitions for pedal that I've seen before include "Power a bike" , "One may be sustaining" , "Foot-operated control" , "part of organ" , "Of or relating to the feet" .)