He's right, you might as well go out and buy yourself an assortment of large sized sockets,
it could be 3/4, it could be 19mm, it could be 15/16"s, 7/8"s, 13/16"s who knows, who cares,
get a whole assortment and no more worrying about it.
You'll need them anyway, the truck wheels are another that take a large size socket,
there are so many things in this business that take large sockets you can take
my word for it that it won't be a waste of money.