The phrase "to kick the tires" means to examine or inspect something carefully before making a decision or taking action. It's like when you check a car's tires for any issues before buying it. Full definition
Without assigning tasks to prospects, you have no way of knowing whether they're truly interested in what you're selling — or if they're just kicking tires and wasting your time. (entrepreneur.com)
There's no expiration date on your free account, so take your time to really kick the tires on this site before committing to receive even more premium benefits. (datingadvice.com)