Trams he crashed: one turning wheel? (7)
I believe the answer is:
hamster
'one turning wheel?' is the definition.
Although both the answer and definition are singular nouns, I can't see how they can define each other.
'trams he crashed' is the wordplay.
'crashed' is an anagram indicator.
'trams'+'he'='tramshe'
'tramshe' anagrammed gives 'HAMSTER'.
Can you help me to learn more?
(Other definitions for hamster that I've seen before include "one running round in circles?" , "Animal" , "Common pet rodent" , "Furry pet" , "Rodent with large cheek pouches" .)