Looks simple enough to repair but not so it turns out. Seat tube is so thin I am amazed so many carbon frames entertain a braze-on and not collar. Yes I know – It allows for variations in tube profile, still not the strongest bit of the frame. I believe Trek have since included a 4th rivet version? Nice. I had to build a fatter cross section to handle future chain suck. Let’s see what Bob says next time he hits the hills in Wales!
(Oops! Just noticed 3rd image is from a Focus braze-on repair from the same week)