Would it Be Stronger to Clip My Belay Biner Through My Harness Tie-in Points?
Look at the strength ratings printed down the side of your carabiner. The strongest axis is along the spine, with most carabiners rating around 20kN to 25kN. However, when a carabiner is cross-loaded, it is roughly one-third as strong (6kN to 8kN). When you clip your carabiner through your two tie-in points, you tri-axially load your carabiner, making it even weaker. Your belay loop is designed to be plenty strong, and clipping it orients the carabiner to be loaded in its strongest direction.
—Ian Nicholson is an AMGA certified rock and alpine guide based in Seattle.