Tires create a seal a wheel rim when air pressure forces the bead (a string of wound metal inside of the lip of the tire) to press against the lip of the rim. Rims have a slight bump the bead has to pass over to create the seal when the tire is being seated. The bead will, occasionally, rise to the maximum tire pressure (44psi for most passenger tires) and not fully seat the bead. Seating troublesome tires requires a little extra effort and lubrication.
Remove the tire from the vehicle if you have not done so already: Loosen the lug nuts of the wheel you're going to remove, using a lug wrench, but do not remove them completely. Raise the vehicle with a jack, being sure to place the jack in the spot recommended in your car's owner's manual. Use a jack stand if you will for any reason place yourself under the vehicle. With the wheel and tire off the ground. Remove the lug nuts from the lugs and remove the wheel and tire.
Remove the valve core using a valve core removal tool. The core unscrews like any bolt.
Spray the area of the bead that will not seat with window cleaner from a spray bottle. The process is easier with ample lubrication. The window cleaner provides that lubrication. Spray down into the gap between the lip of the rim and the bead so that the whole area is wet.
Wrap a ratchet strap around the tire and tighten it down. You want it tight enough to push the tire's sidewalls outward but not so tight that you make the tire tread flat in any area. Basically, you want enough pressure on the ratchet strap to make sure the tire appears inflated and seated.
Attach an air supply and inflate the tire. The bead will seat with the pressure from the outward pressure of the air supply, the lubrication and the inward pressure created by the ratchet strap. Release the air supply and let the air drain out after seating the bead. Remove the ratchet strap.
Reinstall the valve core removal tool and increase the tire pressure to the factory recommended levels. Install the tire onto the vehicle and tighten the lug nuts. Lower the vehicle to the ground and tighten the lug nuts again to factory recommended torque.
