When you say 3.5 do you mean so you can fit a 3.50 tire or do you want to fit a 3.50" wide front rim? What is the bike and how wide are both rims? if it has spokes they will be 1.85 or 2.15 or they may say WM2 or WM3. Rims are much narrower than the tires that they fit.
Generally fitting a wide rim on the front makes the steering heavy and ponderous and the bike less fun to ride, but within reason, it's usually not an issue. Also a rear tire should be wider than the front. A GSXR for instance may have a 3.5" x 17" front and 6.00" x 17" rear.
Old bikes were typically 1.85" x 18" or 19" front and 2.15" rear