Originally Posted by LeonMsport
I wouldn't do it. If you look at the new 5 series, it is rather large (i.e., compared to previous models). I think going down in rim size may throw off the aesthetic balance of the car -- but that is just my personal opinion.
I hear you, and I'm sure I'm in the minority on this (given the general push for 19", 20", etc.), but I've seen quite a few base (non M-Sport) F10 535s and F10 528 with the factory 18" upgrade and I'm generally fine with it (I much prefer the 18" 350 vs. the 18" 237, though).
Anyway, I think my biggest concern is the balance of weight and cost with the notion that this would hopefully "feel" better. 19"+ wheels tend to be heavier for same cost range, and the 245/40/19 tires are often significantly more expensive (avg of like $30/ea, if I recall) and more prone to damage. This latter bit is big trouble for me since I'm in Seattle, head into the mountains in winter oocasionally (not enough to warrant dedicated winters though), and our roads SUUUUuuuck. Potholes and cracked pavement everywhere, craggy concrete, swollen expansion joints, you name it.
Budget and feel are key for me, and I'm willing to trade a little aesthetic brilliance for it. The 18 seemed an ok compromise but I'm wondering if I'm missing some important factor like, I dunno, if lightweight 18"s feel like s__t on these cars for some reason or something like that...