Originally Posted by
Andrew R Stewart
The only thing that gets tired on my bike is the engine

Perhaps Swen means that the binder ears can distort with over tightening, too small a post having been used, poor design, heat induced warping during the building and or poor after construction finishing.
I hope Swen is not trying to imply metal gets soft with time. We all know that, if anything, it's the opposite that happens. Andy.
Probably a mistranslation of metal fatigue into "tired" metal by a non-native speaker. Metal fatigue is caused by work hardening.