Spike of metal close to tyre (4)
I believe the answer is:
tine
'spike' is the definition.
(spike of a fork)
'metal close to tyre' is the wordplay.
'metal' becomes 'tin' (tin is a kind of metal**).
'close to' indicates one should take the final letters (the close/ending of).
The last letter of 'tyre' is 'e'.
'tin'+'e'='TINE'
'of' is the link.
(Other definitions for tine that I've seen before include "Slender prong of fork" , "(Fork's) prong" , "Spike" .)