Was first to replace metal hub in reel strut (7)
I believe the answer is:
swagger
'strut' is the definition.
(I know that strut can be written as swagger)
'was first to replace metal hub in reel' is the wordplay.
I cannot quite see how this works, but
an anagram of 'was' is 'swa' which is present in the answer.
'metal' could be 'er' (Er is an example) and 'er' is present in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for swagger that I've seen before include "Walk proudly" , "Show off" , "Walk with an air of self-importance" , "Move confidently" , "Proud, pompous gait" .)