Chain Grades Explained: G30 to G100 and What the Numbers Mean

Every legitimate chain has a number stamped into its links — 30, 43, 70, 80, 100. That stamp is a strength class, and it answers the only two questions that matter: how much load per size, and what jobs the chain is allowed to do. Here is the ladder, bottom to top.

Grade 30 and Grade 43: general purpose

G30 ("proof coil") is the hardware-store chain — low-carbon steel for gates, swings, and light utility work. G43 ("high test") steps the strength up per size and shows up in farm and logging use. Both are fine at what they do, and neither belongs on a DOT load securement job when higher grades exist at the same weight — and neither may ever lift overhead.

Grade 70: the transport standard

G70 is heat-treated carbon steel, roughly 20 percent stronger than G43 size for size, and it is the load securement chain — the gold chromate finish is recognized at every weigh station in the country. Binding equipment, flatbed securement, towing and recovery: this is the grade the DOT expects, in the sizes and ratings we covered in the chain size guide (3,150 lb WLL at 1/4" up to 11,300 lb at 1/2"). All our by-the-foot chain and chain builder assemblies are G70, matched with rated binders and hooks.

Grade 80 and Grade 100: alloy, and allowed overhead

G80 and G100 are alloy steel — a different metallurgy, not just a bigger number. Alloy chain is the only chain rated for overhead lifting, where a failure drops a load on people. G100 runs roughly 25 percent stronger than G80 size for size, which buys lighter chain for the same lift. Slings, hoists, and crane rigging live here, always with alloy-rated fittings to match — a G70 hook on a G80 sling downgrades the whole assembly to something no rigger will sign off on. The full transport-vs-lifting split is the subject of the G70 vs. G80 guide.

Reading the stamps

Look for the marks on the links themselves: "3" or "30" for proof coil, "43", "7" or "70", "8" or "80", "10" or "100". No stamp, no grade — and no place on a rated job. Color helps (gold usually means G70) but paint and plating lie; the stamp does not.

Picking your grade in one line each

• Utility work around the shop or farm: G30/G43 is fine.
• Securing loads to a trailer, towing, recovery: G70, full stop.
• Lifting anything overhead: alloy G80/G100 with matched fittings — or a web sling built for the lift.

Unsure which world your job lives in? Four questions in the Help Me Choose tool settles it.

Always rig within the rated Working Load Limit. Inspect straps and chain before each use and remove them from service if cut, gouged, excessively worn, corroded, or deformed.