Well, taking a look at the actual failure point of the subframe, it makes perfect sense why it would fail at these exact points. The cylindrical section where the bolts attach are very solid plastic, even without the metal inserts. But where the subframe transitions to the ribbed structures, there is very little surface area at all. Those ribs needed to be quite a bit thicker, IMHO. Obviously, that would have cost weight.
I was literally able to twist these pieces off with my hand with almost no effort. I suspect that for the most part, hard up/down impacts are not the real problem here, as far as failure mode. I think side-to-side or twisting motion is the real culprit. The ribs are very sturdy for up/down strength, but side-to-side motion, not so much. If you get a lot of torsion on the back of the bike, it will start to twist this section.
Also, while the two bottom supports probably get compressed as you add weight to the rear of the bike, the top supports are actually pulled apart (rearward) as downward pressure gets applied farther back.
not my brightest move. Didn't even fall but I know it wouldn't have been that bad on my other bike or correct suspension. Is this crack worth replacing it? It doesn't go all the way through, only what you can see here. I have a spare subframe here but I was hoping to keep it as a spare.
