Nose back to side of road shortly in banger (7)
I believe the answer is:
knocker
'banger' is the definition.
(something which knocks or bangs)
'nose back to side of road shortly' is the wordplay.
'nose' becomes 'conk' (informal term for nose).
'back' shows that the letters should be reversed in order.
'to side of road' becomes 'kerb' (the kerb marks the side of a road).
'shortly' means to remove the last letter.
'conk' reversed gives 'knoc'.
'kerb' with its last letter taken off is 'ker'.
'knoc'+'ker'='KNOCKER'
'in' is the link.
(Other definitions for knocker that I've seen before include "Door banger -- detractor" , "Fault-finder; door item" , "Door rapper" , "Something on door; one continually finding fault" , "Critic" .)