Dreary routine in part of tyre factory (9)
I believe the answer is:
treadmill
'dreary routine' is the definition.
(I've seen this before)
'part of tyre factory' is the wordplay.
'part of tyre' becomes 'tread' ('tread' is part of 'tyre').
'factory' becomes 'mill' (mill is a type of factory).
'tread'+'mill'='TREADMILL'
'in' is the link.
(Other definitions for treadmill that I've seen before include "Apparatus producing rotation" , "It enables one to work out" , "Tiresome job" , "tedious work" , "Endlessly tedious job" .)