I wish I was missing something because I'm confident they would have shipped a piece.

So anyway I got it right and solid now with the wm spacer. I removed the left side 2.5mm dub spacer replaced with 0.5mm spacer, removed the drive side 4.5 mm spacer and tightened it all up.  Haven't taken it out for a spin yet but clearances are ok.  What a pain.

Have the same »problem« with the ZRACE RX 1* : (

For reference: axle length (measured from left crank arm) is 107mm - 2 mm shorter than the ZRACE RX 2* that is 109mm. The ZRACE RX 2* seems to work with both 2.5mm DUB spacer and NO on the drive side of the axle (as SRAM  recommends).

So my guess is the (otherwise pretty nice) ZRACE RX 1* might be fine with a 2.5mm DUB spacer on the drive side and  a 0.5mm DUB spacer on the left and again NO spacer on the drive side.

Since I have no 0.5mm spacer, that's just a theory. Can someone confirm? Oh yeah: thats all for a 68mm BB housing : )