Chrome and alloy wheels have long been a source of problems for slow leaks and bead leaks on cars and trucks. While they look nice and add to the overall appearance of the vehicle, they are prone to corrosion problems that can cause the tyre to not seal properly. This can result in slow leaks around the bead and soft tyres. Air can find the smallest hole to escape from and when corrosion occurs, a gap can appear under the bead.
Determine where the air is leaking. The easiest way to do this is to inflate the tyre and submerge it in a water bath watching for air bubbles coming from part of the tiyre or wheel.
Air leaking from the bead will require the bead to broken down. Break the tyre down with a set of tyre irons of tyre machine if you have access to one.
Remove the tyre completely from the wheel and inspect the inner and outer bead sealing surfaces for corrosion or damage. If no damage or corrosion is present, then check the tire for damage around the beads.
Using a wire brush or buffing wheel, buff the entire bead sealing surface of the wheel until no corrosion or rust is visible. Even if you have noted one spot where the air is leaking, buff the entire surface while you have the wheel and tyre broken down.
Lightly brush the tyre bead with a wire brush to remove any loose rust or debris that might be on it. Light contact is the key here -- you do not want to damage the bead of the tyre.
Replace the valve stem with a new one using a valve stem tool while you have the wheel apart to head off any potential leaks around it. Reassemble the tyre and wheel and inflate the tyre, watching the beads to see that they seat properly.
Place the tityre and wheel back into the water tank to verify that the bead is now sealed and no air is leaking from it. If the bead is still leaking, sealer will need to be applied to the bead.
To seal the bead with sealer, you need to break down the beads. Do not remove the tire from the wheel. Using the brush that comes with the can, apply liberal paint sealer on the bead sealing surface of the wheel all the way around the circumference.
Reassemble the tyre and wheel and inflate it, seating the beads. Allow the sealer to dry for 5 to 10 minutes. With the tyre inflated to the manufacturer's recommended pressure, verify that the leak is gone by submerging the tyre one more time into the water tank.
Tyres are very difficult to mount and dismount with tire irons, though not impossible. If you are not able to do it this way or do not have access to a tyre machine for mounting and dismounting tyres, you may want to take the tyre to your local tyre shop and have them repair the leak. Be careful when seating the beads on the tyre. The high air pressure will cause injury if you have a finger or other body part in the bead when it pops onto the sealing surface of the well.