Been working on my 1958 Evinrude Fastwin 18 and Ive got some down time waiting for parts. In the mean time Im working on the boat trailer. The trailer is in good shape except for the tires. The tires are dry rotted and I also find that the wheels are split rims. When I tried to remove the tires, the tires would not break off the rim bead, so, after unbolting and separating the aluminum wheel I took a utility knife and cut loose half the wheel and tire (see photos). It appears the tires were adhered to the rim and there are no rim beads. What to do? How do you get the tires off? Where can a person get new tires? Whats the procedure for mounting the new tire? Alternatively, is there an adapter that I could use to mount current day wheels on to the 4 bolt vintage axle? Measurements: From outside lug bolt to outside lug bolt the measurement is 4 ¼. The diameter of the hub is 2 ½. The size of the tire is 5.70/5.00 x 8.00 Any thoughts?