When sling angles get shallow or a load can't take compression, a below-the-hook lifting device fixes the geometry. Spreader bars and lifting beams solve different versions of the problem, and the names get swapped constantly — here's the difference and when each one earns its place on the truck.
Spreader Bar: Compression Member
A spreader bar hangs from the crane by two slings to its ends and lifts the load from those same end points — the bar itself is loaded in pure compression. That makes spreaders structurally efficient: lighter and cheaper than a beam of the same capacity. What they need is headroom, because the top rigging forms a triangle above the bar. Use a spreader to: keep sling legs vertical on wide loads (eliminating angle de-rating and inward crushing force), and control long flexible loads like tanks, trusses, and pipe racks.
Lifting Beam: Bending Member
A lifting beam hangs from a single center bail and picks the load from multiple points along its underside — the beam works in bending, so it's heavier for the same capacity. Its advantages: minimal headroom (no rigging triangle), multiple and adjustable pick points for unbalanced loads, and clean handling of loads that need support at specific stations. Low-headroom shops and machinery moves are lifting beam territory.
Choosing
| Situation | Pick |
|---|---|
| Wide load, headroom available | Spreader bar |
| Low headroom | Lifting beam |
| Unbalanced / multiple pick points | Lifting beam (adjustable) |
| Long flexible loads | Spreader (or engineered multi-point) |
| Crushable loads (tanks, crates) | Spreader — keeps legs vertical |
The Rules (ASME B30.20 / BTH-1)
Below-the-hook devices are engineered products: designed to ASME BTH-1, marked with rated load, weight, and serial number, and inspected like cranes — not shop-welded from channel over a weekend. The device's own weight counts against crane capacity. Rig top slings at the designed angle (spreader top rigging is typically engineered for 45–60°), and never side-pull through a spreader.
Fixed, Adjustable & Custom
We supply spreader bars and lifting beams — fixed and adjustable — with the shackles and slings that complete the system. Load, dimensions, headroom, and pick points into the quote form at the top of the page — quotes answered during business hours.