Rubber tyres aren't partly rotating (6)
I believe the answer is:
eraser
'rubber' is the definition.
(I've seen this before)
'tyres aren't partly rotating' is the wordplay.
'partly' indicates a hidden word.
'rotating' says the letters should be written in reverse.
'resare' is hidden within 'tyres arent'.
'resare' backwards is 'ERASER'.
(Other definitions for eraser that I've seen before include "device for deleting things" , "A student's rubber, or the one who uses it" , "Rubber for removing marks" , "Required, should you make a mistake" , "Writing remover" .)