Started before 2010 by some forward-thinking mfrs. The need to impart more strength in the headtube area with less weight penalty than the older one-point-five standard. Trail bike design was on the move toward longer travel, slacker angles more aggressive riding. Something had to be done so frames - - and single-crown forks - - would hold up to the extra stresses.
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Originally Posted by Mark Twain
"Don't argue with stupid people; they will drag you down to their level and then beat you with experience."