For your safety and the safety of others your studs should stick though the lug nut. If the stud thread does not enter into the nut part you are basically holding the wheel on with the thin shank of the lug nut. Buying new longer studs will be a cheap alternative compared to the damage caused by the rear wheel coming off from broken studs. Studs will shear off from lug nuts loosening as the head of the nut breaks loose from the shank. Can you say quarter panel, brake parts, tire and wheel? Yes studs are a cheap alternative.