Originally Posted by Toreador4x4
well from what i have seen, if the bolt pattern is drilled off-center, when you tighten the lug nuts down the lug nuts will pull the wheel where ever they want, reguardless of the ring or not...and you cant run a hub centric ring with a push thru center cap BTW
What he said ^^
Also is for what ever reason your lugs start to come loose, you will feel it shake for a while before too much damage is done. The hub ring will help prevent the rim from moving too much.
As for not being able to install rings with a push through center cap......its been done before....by me.