Zaheer,
These rims are very cool looking and beautiful but I do notice they are for a bike with "right side" disc brake configuration only, that means they cannot fit to Ravi Piaggio unless the front RIM is flipped the other side, but that will make both RIMS spokes to point in an opposite direction.
Secondly as you mentioned that you are using a fat tyre (110-18) these rims are too skinny 1.4' which is even skinnier then orignal Paiggio stock size... if you fit a 110 or 100even it would get "Rounded" insanly and lead to slipping rear tire..
minimum 2.15~2.5' RIM would be a good choice.
hope that helps.