Originally Posted by GregW / Oregon
Thanks for that. Is that the same as use for the X3 (my post #11)? That calcs out to an inch or more smaller OD than stock. Wonder if there is a 125/80-18 available?
Edit: I just found that the Cadillac CTS uses a 135/80-18, which, at ~26.5", would be a little larger than the stock 26.3" rear.
I'm sure you could have an adapter machined pretty easily, but would be nice to find a pre-made one. Do you know the centerbore diameters? X5 is 74.1, so I assume X6 is the same? (M3 CB = 72.56).
Edit: I found the proper hubcentric plastic rings here (74.1/72.56): http://www.1010tires.com/hubrings.as...FU0wpAodcQqcmw $21/set of 4.
That's great. Are you sure about the respective diameters? If so, I'll order the right ring pronto. Thanks for finding this.
My dealer checked the available sizes--at least the ones available a few months ago--and I believe the 125/70-18 tire is the best size available for this use.