Altered setting of foot pedal (7)
I believe the answer is:
treadle
'foot pedal' is the definition.
(I've seen this before)
'altered setting' is the wordplay.
'setting' indicates anagramming the letters.
'altered' is an anagram of 'TREADLE'.
'of' is the link.
(Other definitions for treadle that I've seen before include "Pedal operating machine" , "driving mechanism" , "Foot pedal for power" , "Foot lever working machine" , "Alerted (anag)" .)