Originally Posted by
tds101
I confused weld failure with metal fatigue. We've seen multiple bike frames fail in this forum, and most all were at the weld, where it happened almost instantly. These were all aluminum framed bikes...
It's not surprising that the occasional weld failure is reported. Aluminum frames have represented the vast majority of adult bike sales since at least the mid-1990's,
Aluminum bikes replaced steel bikes in the market for a simple reason.
Steel bikes can be moderately durable and somewhat affordable (and heavy; Surly's hipster marketing made heavy steel frames an acceptable alternative to aluminum) or moderately light and expensive.
But using aluminum made it easy for manufacturers to provide affordable frames with a good margin of strength while keeping the weight reasonably low.