It could describe wheel turning red, perhaps (13)
I believe the answer is:
revolutionary
I believe this is a double definition.
'it could describe wheel turning' is the first definition.
'red perhaps' is the second definition.
(red can mean a leftwing revolutionary)
(Other definitions for revolutionary that I've seen before include "agitator" , "New" , "Innovative" , "Causing dramatic change" , "Insurgent - involving dramatic change" .)