Thinking this was a Momo wheel, I grabbed it from a 320i at the junkyard:
Turns out it's got a Nardi mounting pattern (74mm PCD, 6mm holes @ 1,3,5,7,9,11 o'clock), not Momo (70mm PCD, 6mm holes @ 2,4,6,8,10,12 o'clock).
Overall diameter is 13 inches; the center hole is a bit over 60mm. The cover is vinyl.
Was this a common wheel on E21s? Other '70s BMWs? What's it called? Is it, in fact, a Nardi wheel?

