There was another thread running on this, but I thought I'd summarize here to make the info easy to find. Thanks to Tom Tarzian for a lot of the work on this. The goal was to come up with a compactg spare solution that would clear the stock brakes w/o a spacer and come as close as possible to the stock tire OD.
To clear the front brake requires an 18" wheel, or perhaps a heck of a spacer on a 17. The X6 has a 5" wide wheel that seemed to fit the bill. Only thing is its hub is slightly larger (74.1 vs. 72.6 mm), so a centering ring is the right way to go.
Finding a suitable tire was a challenge, because manufacturers don't seen to list info on compact spares, and most tire dealers are unclued. I eventually found a 135/70-18 as used on the Cadillac CTS, and was able to track down the manufacturer (Maxxis) and a local dealer (Les Schwab). I took about two weeks to order in.
I test fit the setup today, and it clears the front brake caliper by about 1/4", and seems just fine. The OD of the tire is just about 0.3" smaller than the sotck fronts (a little more in the rear, of course), but seems well within tolerance, IMO. Tom had used a 125/70, but I thought that a little small.
Weight complete is 37 lbs. (47 bs. for OEM 19F). The stock lug bolts work fine.
So, here's what you need:
- BMW 36-11-6-768-861 black steel wheel; $155 list
- BMW 36-12-1-116-326 rubber valve stem, $5.35 list
- Centering ring, 74.1-72.6 mm; 1010 tire (mis-labeled 74.1-72.56 http://www.1010tires.com/hubrings.as...FU0wpAodcQqcmw
); $30 shipped for set of 4 (you can sell extras)
- Maxxis T135/70R18 104M M9500N (#TP10655100), $85 + $10 shipping + $12.50 mount & balance
All-in-all, not inexpensive, but a nice bit of security to have in the trunk for trips, and about half the size of a full-size spare.