Vehicle turns round (6)
I believe the answer is:
wheels
I believe this is a double definition.
'vehicle' is the first definition.
(I've seen this before)
'turns round' is the second definition.
(I've seen this before)
(Other definitions for wheels that I've seen before include "Spins on an axis" , "turns round" , "Turns in a wide curve" , "Car (informal)" , "Circular frames with spokes" .)