Mavic Rims

Below pics of a double eyeletted Mavic rim which cracked at about every spokehole inside and out. The rimsurface shows very little braking wear, and it is believed that the rim only did about 3000 km's worth of cycletouring. Luckily the rim stayed true enough to complete the tour! 
This rim is a D 121 CD,  28mm wide (downhill), with dark grey anodizing and certainly not very light with a claimed weight of 530 grams.  Mavic describes this rim as featuring  'bomb proof strenght' and a best use of  'heavy loads'. 
This rim was superseded by the D521 (single eyeletted) which cracks less spectacular as the more triangular shape flexes less, and because forces are not transfered to the inner wall. That doesn't make it more reliable, at least on this trip the D521's fitted to a second bike cracked too.
 

When the bottom of the rim goes, the crack in the upper half grows rapidly.
 

Note the progressing crack above the spokehole on the right, almost every hole was affected in this manner
Through the gaping hole on the left you can see how it all started: with cracks starting from underneath the eyelet