2.5 or 3.5??? I measured the circumference of the front hub and then figured the diameter from that (Diameter = Circumference divided by Pi…10 11/16 divided by 3.14) and came up with 3.5”. I have been wrong before, and I’m not a math expert, but I have spent the night in a Holiday Inn Express. LolI made a template for the hole with wood and made the cut slowly and using tons of cutting fluid and a 2.5 hole saw. It took a while get through the steel but it worked. Cleaned it up and powder coated the wheels in Wimbledon White. They are solid and don't wobble at all at high speeds.
Randy