||02-18-2019 04:49 PM
When I changed my first tire over 60 years ago I was taught a simple test that has served me well over the years. Many leaks occur at the valve stem's core. That little thing that is unscrewed to let air out and is depressed when checking tire pressure. If you check air pressure, before putting the cap back on just spit on your finger and wipe it over the open end of the stem. No bubble, replace cap. If it bubbles use a valve core tool (some metal caps have them included in their construction) and check to see core is tight. DON'T over tighten. Not all valve caps seal well, especially if they are the plastic type. Merely meant to keep dirt and water out with the removable core (schrader valve) being the actual seal.
If the tires are replacement tires often the tire changer (person) doesn't bother to make sure the bead surface on the wheel is clean and clear of all bits of rubber from the old tire. Bead leaks can be slow, annoying, and hard to find unless you remove the tire/wheel assy and immerse it in a vat of water. Spraying a soapy solution around the bead on both sides of the tire, waiting a few minutes, then looking for a froth of bubbles, will reveal a leak.
For the first go around I'd merely add air to the tires and check regularly to see if they still loose air.
For me, even though I spent almost my entire working life around tires I just let my local dealer handle issues like this. I buy all my tires from him without a bunch of shopping around and in return I get all kinds of maintenance services at no charge (flat repair, rotation, pressure check, etc).