Change of speed before pace is reckless (9)
I believe the answer is:
desperate
'reckless' is the definition.
(I've seen this before)
'change of speed before pace' is the wordplay.
'change of' indicates an anagram (the letter order is changed).
'before' says to put letters next to each other.
'pace' becomes 'rate' (synonyms).
'speed' anagrammed gives 'despe'.
'despe'+'rate'='DESPERATE'
'is' is the link.
(Other definitions for desperate that I've seen before include "Extremely dangerous (situation)" , "Eater sped to beyond hope" , "Extremely bad or serious" , "critical" , "Hopeless; extremely bad" .)