If they are oldish rims then take them back to where you got the tyres fitted - have them take the tryes off & check the inside of the rim for corrosion (ALL ALLOYS GET IT) get them to clean them up with the buffer wheel & apply bead sealer when fitting back up - i take it they did change the valves?

The test for you to do is to get a bowl of very soapy water & apply to the rim of the tyre & rim of the wheel to see if it bubbles if it does you have a leak - the other thing to check is the valve with the same method - if no leak found take off wheels & check inside rim with the method again.

Other than that there is nothing else to try !!!


Hope this helps