Paces of trades varies (6)
I believe the answer is:
treads
'paces' is the definition.
(I know this)
'trades varies' is the wordplay.
'varies' is an anagram indicator.
'trades' with letters rearranged gives 'TREADS'.
'of' is the link.
(Other definitions for treads that I've seen before include "Sets the foot down." , "Puts the foot down" , "Stared at tyre surfaces" , "mates" , "Steps, walks" .)