+1Why are you limiting your selection to just 15"?
There are many wheels out there in the 16-18" size that will fit your car w/o clearance issues. Just keep the wheel offset under et20mm and the tire size width around 235mm max.
I personally think that the 17 wheels look best on the 6er. If I were to go 16s, I would also go staggered widths. maybe 8" wide fronts and 9"/9.5" rears. I think the only 16s I would spring for would be the BBS RSs or Open Lug ALPINAs, but they are pricey. AND oooooh so beautiful on the E24. Tires for 16s and 17s are pretty much the same, and are available from everywhere. I recommend TireRack to get your tires. Great prices, programs and service. Have Fun! Now the hard part is how to decide which one...hahaha:rofl:I had put E39 15" wheels on my 88 only because I got a good deal on the wheels and tires. Tires for the 15's are gettting hard in my area to find so do as other's say and go with 16" and up. There's a pic in my album of the 88 with the E39 wheels on it.
I gotta sit down....I`m flashing back to "Miami Vice"....Here is a set that would look great on your 635. The offset and size is perfect.
So did you decide on new wheels yet?This is probably old question for some, but I need to replace 390 rims with a 15" option. Does anyone know if a particular BMW rim is best/better suited I have been told use any and I have heard this is big issue with spacers, etc. Any help