kick tires
To examine or inspect a second-hand car or cars for possible purchase; to shop for used cars in general. I always loved going to used car lots with my dad while he went around kicking tires. Our old van finally broke down, so I'm heading out this weekend to kick some tires.
kick the tires
To inspect or test something or someone to ensure that he, she, or it meets the required or expected standard of quality. Primarily heard in US, Canada. You should always kick the tires of anything you plan to buy from someone online, or else you might end up buying a piece of junk! The boss always assigns difficult projects as a way of kicking the tires of new employees. We should hire a few interns to kick the tires on this app before we release it to the public.
spare tyre
1. A layer of excess fat around one's midsection. Primarily heard in UK. I think I need to lay off the lager, because this spare tyre of mine is getting a bit out of hand.
2. An unhelpful, unnecessary, unproductive, or unwanted person in a group. Primarily heard in UK. There are a few spare tyres on this project who are really holding back our progress. Ever since John's girlfriend started hanging out with us, it's left me feeling like a spare tyre.
tire kicker
1. One who examines or inspects a second-hand car or cars, often without really intending to buy anything. Primarily heard in Australia. This guy isn't a serious buyer, he's just a tire kicker.
2. One who wastes another's time. We need serious candidates for this position, so make sure to eliminate any tire kickers.