I didn't read the whole thread and I have absolutely no knowledge what-so-ever regarding wheels so, I felt compelled to post my opinion.
I believe the wheels failure was due to the roundness of the wheel in relation to the composition and flatness of the street. If the street was not flat, or the wheel was square, then the ride quality would have been affected by the air density found at the lower altitudes.
ADV1, do you care to comment?
2011 Le Mans Blue M3// Black extended Novillo w/ Blue Grey Aluminum trim/DCT/ZTP/ZCW/ZPP/ZCP Premium Sound ///Akrapovic Evolution Exhaust
2015 Audi S4 Prestige, Brilliant Black S-tronic
2012 Le Mans Blue 135i M Pkg DCT