Here's what rims I believe you have;
1960-66 Ser 50-60....(8-3/4" dia. bolt circle, 6-1/4" dia. pilot hole)...p/n 2395277
2395277 is a 2-piece riveted 20x6.5 wheel with a 6" offset....8.25x20, 10-12 ply; 9.00x20 10-12 ply tire size, tube type, 10 stud.
So, you need to look for 22.5" (Tubeless) 10-lug Hub Piloted rim with 8-3/4" dia. bolt circle and a 6-1/4" dia. pilot hole....p/n 3765587.
Note, ALL 22.5 rims are 1-piece Tubeless and ALL 20" rims are 2 or more piece Tube Type.
Mike B
