I know what it means to kick tires, but I’m wondering how the practice ever got started, where it came from, who coined the phrase, etc.
In the days when tires used high pressure, you kicked them to make sure they were inflated properly.
The practice continues today in the trucking industry where a driver will “thump” the tires. Some folks say they can tell that a tire is properly inflated by the pitch of the “thump” - and there have been plenty of demonstrations that they are wrong.
Never understood it but there are 2 kinds of people-- tire kickers and fender thumpers. No harm comes from either but it’s funny to watch. LEE
No idea how or where it originated, but I would imagine it would have something to do with a potential car buyer thinking they’re mechanically inclined. They kick the tire as a momentary test to see if the wheel is solid on the suspension.
Way back when, a worn suspension part would have been more noticeable; especially in the days of kingpins, etc.
As to truckers, the rumor I hear is that they’re using those tire clubs to chase away rubber fleas. 
The term used in naval aviation is “kick the tires and light the fire”.
I think it came from us truckers that didn’t really feel like putting a tire guage on every tire, every time we go out on the road. So we just walk around and kick them to make sure they aren’t too soft. You get used to the feeling of it to know if they are okay or not after a while.
Thanks for the replies, there’s some interesting ideas that seem quite plausible, but I was hoping that there might be a bit more.