do i really need spigot rings?

[mk3tina]

on my mk3 cortina ive got a pair of WELD Draglite wheels on the back of it (came from a 4 stud mustang), however the centre bore hole in the wheels is bigger than standard ford (not to mention they use special sleeved wheel nuts) . they have been on the car a while and its been drove a little with them on and it drives fine, however i was wondering if i should get some spigot rings made up for them. i only have them on the rear if that makes a difference.

[bortaf]

I would, the studs aint really up to taking the weight of the car or more importantly absorbing an impact (like driving off a curb at speed, they may snap) twin wheel transits use the studs and not the centres to take the weight but they are a lot thicker than car studs or even the single wheel vans, they use the centre to locate/carry weight and use the same studs as the cars

[you'll get 10s on that]

Not strickly needed . The tube nut tolerance will ensure a certain element of concentricity. In relation to the sheer effect on the studs remember that clamping force is about ten times greater than rotational force so shouldn't be an issue. More inportant is that you torque the wheelnuts to the correct setting which on a Mk 3 Tina will be 60~65 ft/lbs (12x1.5 thread)