Hi Juan,
Huge down side. You will have to run a really narrow tire with a 2.15" rim. Not a good idea. Your other option would be to go with an 18 X 3 (or 3.5) rim and a new 120 or 130 tire. You would also want to modify the brackets on the front fender though as there would be a large gap between the tire and the fender.
John