Tape didn't seal perfectly, air leaked into the deep rim section which got pressurized, failed at the attachment point with the brake track because that area of the rim isn't designed to be loaded that way?
Yes, exactly! Except to be clear, the tape did
"seal perfectly" over the spoke holes. In fact, it was only because the spoke holes were sealed that the wheel was then in position to be destroyed by air pressure.
I think many of us have understood that the purpose of tape is to seal the spoke holes, because once you have those sealed, and a valve stem in place to seal the valve hole, that air will then leak until the tire is seated in the rim bed, and that once you have those three areas sealed - (1) spoke holes, (2) valve hole, and (3) tire/rim bead - the tire is seated, wheel holds air and you are good to go.
But ENVE is insistent that you use their rim tape. It is wider than Silca tape, and covers much more than the spoke holes. It covers all the way to the rim bead. Why is this so important? Because it would seem that some (or all) ENVE rims have small holes/cracks/fissures in the rim bed/rim bead area. We'll call this area (4) - in addition to (1), (2), and (3) above.
So now you're seating the tire and once you get (1), (2), and (3) sealed, your air source, rather than pumping the tire up to its desired air pressure, is now pushing air out through tiny area (4), in this case right into the hollow area consisting of the side of the rim and BAAMMM! Total rim destruction.
Posting so no one makes this same mistake. I really do think Enve should make clearer in their website/written materials that using non-Enve tape can result in catastrophic rim failure.
Race Director, Velo Club La Grange (http://www.lagrange.org
) https://www.strava.com/athletes/337152 https://vimeo.com/user11846099