Vehicle part worn around the waist? (5,4)
I believe the answer is:
spare tyre
I believe this is a double definition.
'vehicle part' is the first definition.
'worn around the waist?' is the second definition.
(informal term for fat around the waist)
(Other definitions for spare tyre that I've seen before include "one prudently has in car" , "Roll of fat around the tummy" , "It's carried in case of a blow-out" , "Roll of fat round waist" , "Roll of fat around the waist, like car part" .)