Irrespective of the frame material, if your bike takes a hit or the shifting gets weird, have us check the derailer hanger. We can straighten or replace it.
Weak hangers flex minutely under load when downshifting, especially under power. If you ever wondered why your bike shifts OK on the stand but not on the road, or have been unable to dial in even a new system and alignment isn’t a question, your derailleur hanger could be part of the problem.
(Aside: Another trend among bikemakers—the return to the internal cable routing craze—can also be a culprit because of the increased friction. Dear bikemakers: Unless it’s an aero road or TT bike, rout cables outside the frame! Internal routing is a pain in the ass, and I hope this trend dies as fast as it did the last time around.)
Or buy a metal bike. Progress is hell.