If I remember correctly, the stock 15" 15-holes on the W126 are 205/65/15 on 15x6.5 ET+25 wheels.
I use this site, WillTheyFit to give me a rough estimate on how things are going to look when I change wheels/ tire sizes. Put in the stock setup and put in your new setup and see how they compare, and make the necessary adjustments from there.
So it looks to me like I would need a 1/4 inch spacer to put it to the old offset and it would be 3/4 inch (1/2 inch from rim and 1/4 from spacer) or am I over thinking this? I would end up with about 3% error on the speedo meaning 62 to really be at 60. All things I could live with if I read that correctly.
BenzWorld.org forum is one of the largest Mercedes-Benz owner websites offering the most comprehensive collection of Mercedes-Benz information anywhere in the world. The site includes MB Forums, News, Galleries, Publications, Classifieds, Events and much more!