Admit defeat, finding new wheel not worth it (5,2,3,5)
I believe the answer is:
throw in the towel
'admit defeat' is the definition.
(synonyms)
'new wheel not worth it' is the wordplay.
'new' indicates anagramming the letters.
'wheel'+'not'+'worth'+'it'='wheelnotworthit'
'wheelnotworthit' is an anagram of 'THROW IN THE TOWEL'.
'finding' is the link.
(Other definitions for throw in the towel that I've seen before include "admit defeat" , "Cave in" , "damp condition suggests one might?" , "surrender after trading blows?" , "Give oneself up" .)