here's a BMW wheel size chart...w/hub sizes up to (but not included) F bodies
BMW 68MM Centre Cap x 1
BMW M Sport Logo Alloy Wheel Centre Hub Caps 68mm size x4 caps on eBid United Kingdom | 181137191
50mm center cap roundel?? | BMW 2002 and other '02
E70 x5m center bore - XBimmers.com | BMW X6 Forum X5 Forum
Solving Rear Wheel fitment by Swapping Rear hub to lower offset & reduce fender work - BMW 1 Series Coupe Forum / 1 Series Convertible Forum (1M / tii / 135i /
74.1 - 72.6 Spigot Rings Set of 4 Hub Rings BMW Wheels | eBay
Anybody know the size of M235i wheel "hub cap"? - 2Addicts | BMW 2-Series forum
Hub Diameter, Wheel Centre Bore and Spigot Rings Explained » Oponeo.co.uk
BMW Wheel Info and Tech Tips
Wheel Hub Hole Size - BMW 3-Series (E90 E92) Forum
Oem wheel center cap size - BMW X5 and X6 Forum (F15/F16)