Spiked wheel — gardening tool saving time? (5)
I believe the answer is:
'spiked wheel' is the definition.
(I've seen this before)
'gardening tool saving time?' is the wordplay.
'gardening tool' becomes 'trowel' (I've seen this before).
'saving' is a deletion indicator (saving can mean except).
'time?' becomes 't'.
'trowel' with 't' taken away is 'ROWEL'.
(Other definitions for rowel that I've seen before include "Goad" , "Spur spike" , "Spur spikes" , "Spur's spiked disc" , "Part of a spur" .)