I by no means would say 550 is the optimal shoe string. However my first two months in Afghanistan had the boot laces on both of the boots pictured above frayed and snapped. Options for boot laces are a little limited so 550 was the logical answer. The 550 has held up with no fraying and I haven't had the knot come untied on me. To tie it I put a simple over hand knot in the end of the lace on both ends. Then I tie your standard shoe lace bow without double knotting. After complete I continue to pull the loops until the knots in the end of the laces lock the knot and the loops can't get any bigger. Then I tuck the loops in the side of my boots.