Disadvantages of support during ties (9)
I believe the answer is:
drawbacks
'disadvantages' is the definition.
(drawback is a kind of disadvantage)
'support during ties' is the wordplay.
'support' becomes 'back' (back is a kind of support).
'during' means one lot of letters goes inside another.
'ties' becomes 'draws' ('draw' can be a synonym of 'tie').
'back' placed inside 'draws' is 'DRAWBACKS'.
'of' acts as a link.
(Other definitions for drawbacks that I've seen before include "difficulties" , "Snags" , "Disadvantages, hindrances" .)