Stock Wheel HUBS...

[JamLazyAss]

Are the front and rear hubs the same?   
 
The reason I ask is because I have a nice Panhead wheel that I wanted to run on a Servi-car, but the hub doesn't seem to fit the brake drum.

[Ohio HD]

Part number 43540-36 will fit as below.

UL 1937-1948 front or rear
WL 1936-1952 rear only
EL 1936-1940 front or rear
FL 1941-1966 front or rear

[SP33DY]

1937 to 1966 big twins, UL, EL, & FL, are the same hub front and rear. My 1954 Spare parts book says the big twin hub is not interchangeable with 45 Solo front, and Servicar rear.
Big twin front & rear, 45" Solo rear 43546-36
I think 43599-30 is the hub/drum assembly for 45" solo front wheels and Servicar rear wheels. They have short spokes from the outer edge of the brake drum to the rim, and long spokes from the hub to the rim.