There were at least 3 different sizes of Budd style nuts. The most common are 3/4-16 inside and 1-1/8-16 outside. Some are 15/16-12 inside and 1-5/16-12 outside. Then there is a metric version that is M20 inside M30 outside. I think they all use 13/16 or 21 mm square on the inner nut but the outer nut is 1-1/2 hex on the common one, 1-3/4 on the heavy one, and 1-5/8 or 41mm on the metric one.
FWIW, I hate budd wheels. I used to work on rusty old Freuhoff trailers with budd wheels. The right side is left hand thread (or is it the other way around?). About every 10th outer nut one you try to take off will either spin in the rim and loosen the inner nut leaving the outer and inner nut stuck together in the outer rim, or even worse, it will push the stud back into the brake drum and leave you with the nuts captured on the outer rim.
I have a special wrench that clips on the ID of the rim to drive the inner nuts through the outer nuts when they come off together. What a pain in the ass. And I can't count the number that I had to heat up or that stripped or that broke off the stud as soon as you touched the inner nut.
