Our write comes from a root that means to shred..
This I find hard to believe - where is the semantic connection? And indeed, the OED has: The relationship of the stem wr_t- to Du. and LG. forms without w (MDu. and MLG. rīten, etc.) is doubtful
German "reissen" has two rather distinct meanings, which possibly have separate roots: "to draw" (still to be found in "Reissbrett" = drawing board), and "to tear".