I just bought a 1460 and it has 30.5 -32 on the front and 18.4-16.1 steer tires on the back. I was wondering if it was possible if I could put 23.1-26 or 28l-26 on the front and leave the 18.4-16.1 on the back and still be under 12 feet 8 inches if not what size of tires would I need and where would I need my final drives and my back axle set at?