Can someone please explain to me why shouldered lug nuts are helpful? I'm running 2 inch adaptors and had never even heard of them until a month after I got them. I have mine bolted on with regular closed in chrome lug nuts.

 

it all has to do with the seating surface of the rim and the mating of the lug nut

Not familiar with spacers but would imagine it works the same

google image "lug nut seat type"

 

Adaptors