Q:

BMW E30/E36 (and others) rear differential. Anybody know what size joints these are/what the pitch circle is? Anybody know how much these diffs weigh? Anybody know what the spline pattern on the end of them is? (28 by what diameter?)

http://picasaweb.google.com/hugh.mccabe/BMWE30M3Project...#5104332800624268290
http://picasaweb.google.com/hugh.mccabe/BMWE30M3Project...#5104332852163876050
http://picasaweb.google.com/hugh.mccabe/BMWE30M3Project...#5104332856458843362

I'd like to run an E30/E36 "medium" size BMW differential with Miata uprights/hubsdriveshafts in a one-off vehicle if at all possible (Miata corners are convenient, but I need a tall ratio and lsd at sensible cost. Miata never relly made a tall ratio, and the specMiata folks nab all the lsds in short order anyhow)

Email sent.

As far as I can gather they're a large lobro joint, and thanks to Jason the old "big six" differentials are 38kg/83lbs apiece.

They're the 108mm OD, 94mm pitch circle Lobro joints on the "medium" BMW diff, with 84mm pitch circle on the input flange.

SW2007 model available if needed.

Miata driveshafts have a 4x100 bolt pattern on the ends. Not had it apart to chekc splines yet.