A further note. 'In theory' PF30 is good because it comes down to the 'cylindricity' of a 46mm ID hole in a carbon shell if this can be controlled to a tight tolerance. It could be argued that a PF30 hole can be controlled tighter then two insert molded bearing cups...but probably not a single one if both bores are shared. In the case of PF30 it really comes down to the 'process' of the crankset installer if subscribing to the use of adhesive to pressed in Delrin bushings. If pressing in Delrin bushings and NOT immediately installing the crank and adjusting preload...if you use say epoxy or Loctite, now the bushing bores centers are misaligned and bearing drag will be increased if the adhesive sets up prior to installing the crank which aligns cups and bearing bores. The corollary to this and counterpoint to using adhesive is....if you don't use adhesive and the bores are misaligned which they will be based upon a given tolerance....then the crank will align them and the bushings will dislodge at some level. This is precisely why Specialized changed their narrow PF30 what they call carbon OSBB installation procedure I linked...too many Delrin bushings lost their seat and support which causes them to squirm and lose their shape and fail...what happened to the OP's Foil.