Sling Tension — Unequal Legs / Offset CG
Per-leg tension for a 2-leg lift with the centre of gravity off-centre — the short leg takes more.
When the centre of gravity sits off-centre, the short leg quietly takes the majority share — calculated here via the CG offset. Riggers who 'even it up by eye' discover the imbalance mid-air; the proper fix is measured CG and legs sized for the heavy corner.
Formula
Note: Rigging and crane decisions are life-safety critical. This calculator is a planning aid — the load chart, sling tags, site lift plan and a qualified lift director govern every real lift.
Per-leg tension for a 2-leg lift with the centre of gravity off-centre — the short leg takes more. A free crane load, wind & rigging safety tool — no sign-up, no upload, instant results in your browser.
About Sling Tension — Unequal Legs / Offset CG
Sling Tension — Unequal Legs / Offset CG computes the governing relationship T_A = W·(L−x)/L ÷ sinθ · T_B = W·x/L ÷ sinθ live as you type. When the centre of gravity sits off-centre, the short leg quietly takes the majority share — calculated here via the CG offset. Riggers who 'even it up by eye' discover the imbalance mid-air; the proper fix is measured CG and legs sized for the heavy corner. Defaults are pre-filled with realistic values for this exact scenario, and the worked example substitutes your numbers step by step so the math is never a black box.
How to use Sling Tension — Unequal Legs / Offset CG
- 1Enter your values — Load weight, CG distance from pick A, Pick A to pick B distance, Sling angle from horizontal (sensible defaults are pre-filled).
- 2Read the live results: Leg A tension, Leg B tension.
- 3Check the "with your numbers" line to see T_A = W·(L−x)/L ÷ sinθ · T_B = W·x/L ÷ sinθ substituted step by step.
- 4Adjust inputs until the scenario matches yours, then copy or share the result.
Why use Sling Tension — Unequal Legs / Offset CG?
- ✓Instant, free and private — every calculation runs client-side in your browser; nothing is uploaded
- ✓Built on the stated formula T_A = W·(L−x)/L ÷ sinθ · T_B = W·x/L ÷ sinθ with authoritative sources cited on the page (ASME B30.5/B30.9/B30.20 — Cranes, slings and below-the-hook devices; Wire Rope Technical Board — Wire Rope Users Manual, 4th ed.)
- ✓When the centre of gravity sits off-centre, the short leg quietly takes the majority share — calculated here via the CG offset.
- ✓SI ⇄ Imperial toggle converts your inputs in place, so you can work in the units your drawings use
Frequently asked questions
What formula does the sling tension — unequal legs / offset cg use?+
It evaluates T_A = W·(L−x)/L ÷ sinθ · T_B = W·x/L ÷ sinθ, exactly as published. Sources: ASME B30.5/B30.9/B30.20 — Cranes, slings and below-the-hook devices; Wire Rope Technical Board — Wire Rope Users Manual, 4th ed.. The substituted worked example on the page lets you verify every step against the textbook.
How should I read the result — and how far can I trust it?+
When the centre of gravity sits off-centre, the short leg quietly takes the majority share — calculated here via the CG offset. Rigging and crane decisions are life-safety critical. This calculator is a planning aid — the load chart, sling tags, site lift plan and a qualified lift director govern every real lift.
When is this calculator the right tool for the job?+
Per-leg tension for a 2-leg lift with the centre of gravity off-centre. Riggers who 'even it up by eye' discover the imbalance mid-air; the proper fix is measured CG and legs sized for the heavy corner. For neighbouring scenarios, the related tools below cover the same engine with different presets.
Does it support both metric and imperial units?+
Yes — the SI ⇄ Imperial toggle converts the values already in the fields, preserving the physical quantity, so you can flip mid-calculation without re-entering anything.
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