if he did run directly into something, the crease in the downtube that you mention is to be expected. However, the tube(s) should bend, not just pop apart cleanly like that. What I can see from the pictures sure looks like inadequate penetration at the head tube welds (which would be TIG). I've seen many bikes crashed, running into cars and other seriously immovable objects. The tubes buckle and bend. The fork may bend. But the mitered joints do not pop apart. Look how "clean" the separation is ! I'd suspect that the TIG welder was not set to the right voltage, sufficient to get full penetration and a large enough bead for an adequately strong joint..
REI house brand bikes (Novarra) had a spate of these about 10 years ago - "just riding along" and the head tube separated. Like they got past QA, got painted and shipped, and then failed while riding.
I sure would like to look at one that came from the same batch as the indcident bike. I wonder if visual inspection would show the lack of a weld bead.
Mark Petry
Bainbridge Island, WA USA
Last edited by mpetry912; 12-05-19 at 11:10 AM.