Rod could be a larger than normal bloke, ultimately (4)
I believe the answer is:
axle
'rod' is the definition.
(axle is a kind of rod)
'be a larger than normal bloke ultimately' is the wordplay.
'larger than normal' becomes 'xl' (I can't justify this - if you can you should believe this answer much more).
'ultimately' indicates one should take the final letters.
The final letter of 'bloke' is 'e'.
'a'+'xl'+'e'='AXLE'
'could' acts as a link.
Can you help me to learn more?
(Other definitions for axle that I've seen before include "Shaft on which wheels rotate" , "It's pivotal" , "Pin on which a wheel turns" , "Bar on which wheel revolves" , "Rod attachment to wheels" .)