hub centric ring question

[SoleMate]

I need hub centric rings for my 18" Carlsson 1/5s. I know that there are 2 diameters needed, one of the wheels and one from the car. For a 98.5 B5 1.8t what is the diameter on the car I need? Thanks.

[DoubleAudi]

if those wheels where or a mercedes you need a 66.56-57.1. I can get them for you for like 25 bucks. let me know