Full size spare for 09 MCS 17's...
 

I have a bulge in the sidewall of one of my runflats, so I'm going to ditch them for normals. Buuut... I was wondering if I should keep a runflat as a full size spare for emergencies on long trips.
Is this a good idea?

I was going to pick up a spare 17" Crown Spoke to swap with my curb-rashed one.

Single rims are proving hard to find- about to gulp and call the dealership. Would it be even crazier to buy new 17" rims and still keep a full size Crown spoke with a run flat as an emergency? If a front wheel goes, I could still put the runflat on the rear. Since the "donut" I see for sale can't fit the S on the front anyway, I'd need to shuffle it to the rear anyway.

Is this crazy or stupid or both? :)

many (including myself) have just bought a tire repair kit (about 20$) when ditching runflats for normals...

Yeah, I plan on getting a mobility kit, but I also plan on long road trips where I would rather have a spare for emergencies, if I am off major roads, etc.

Does anybody have winter tires mounted on separate rims?

Seems like that would be nice, could grab one to throw in the back on longer trips.