Flatbed load securement: how many tiedowns, what they're rated for, and when to check them

A load that shifts or falls is the most dangerous mistake a flatbed driver can make, and roadside inspectors look at securement on every flatbed they stop. I'm Steve, lead dispatcher at TruckSprint. Flatbed, step deck and hotshot are three of the equipment types we dispatch, and this guide covers the federal rules all three share, with a calculator for the math.

What the rules require

Federal cargo securement rules apply to trucks, tractors and trailers, and the core requirement is simple: cargo must be loaded and secured so it can't leak, spill, blow, fall or shift enough to affect the vehicle (393.100(b) and (c)).

The system has to hold up under set forces (393.102):

You don't calculate g-forces at the shipper. The tiedown rules below are how you meet them in practice.

The two minimums

1. Count by length (393.110). If the article isn't blocked forward by a headboard, bulkhead or other secured cargo:

• 5 ft or shorter and 1,100 lb or less: 1 tiedown
• 5 ft or shorter and over 1,100 lb: 2
• Over 5 ft, up to 10 ft: 2
• Over 10 ft: 2, plus 1 for every additional 10 ft or part of 10 ft

If it is blocked forward, you need at least one tiedown per 10 ft of length, or part of it.

2. Aggregate working load limit (393.106(d)). Add up the WLL of the tiedowns securing the article: it must be at least half the article's weight. How each one counts depends on how it's attached:

• From the vehicle to the article, or over it and back to the same side: half its WLL.
• Over or around the article from one side of the vehicle to the other: its full WLL.

Run your load through both:

In the default example, a 24,000 lb, 24 ft article needs 4 tiedowns by length, and 3 straps at 4,000 lb over the top by WLL, so 4 is the minimum. Make it 46,000 lb on a short 6 ft article with 3/8 in Grade 70 chain, and the WLL rule takes over.

Default working load limits

If a tiedown is marked with its WLL, use the marking. If it isn't, 393.108 sets defaults:

Source: 49 CFR 393.108, tables of working load limits · checked 2026-10

Unmarked chain counts as Grade 30 proof coil, and a tiedown's WLL is the lowest of any component, tensioner or the anchor point it's hooked to (393.108(a)). A 4-inch strap on a weak stake pocket is only as strong as the pocket.

Attaching and protecting tiedowns

• No damaged gear. Cuts, cracks or worn webbing that reduce the WLL take a tiedown out of service (393.104(b)).
• No knots in tiedowns (393.104(f)(1)).
• Tight and locked. Each tiedown must be fastened so it can't loosen or release in transit (393.104(f)(3)).
• Edge protection wherever a tiedown would be cut or worn at a contact point (393.104(f)(4)). Steel edges eat straps.

Checking the load on the road

Under 392.9(b), the driver must inspect the cargo and securement within the first 50 miles of a trip, then re-check and adjust whenever:

• you change duty status;
• you've driven 3 hours; or
• you've driven 150 miles,

whichever comes first. Straps loosen as loads settle, especially lumber, pipe and anything that compresses. Build the stops into your trip plan; they also count as on-duty time under the hours of service rules.

Commodity-specific rules

Some cargo has its own rules in 393.116 through 393.136, which apply on top of, or instead of, the general rules:

• Logs; dressed lumber and similar building products
• Metal coils; paper rolls
• Concrete pipe; intermodal containers
• Automobiles, light trucks and vans; heavy vehicles, equipment and machinery
• Flattened or crushed vehicles; roll-on/roll-off and hook-lift containers
• Large boulders

If you haul any of these, read that section in full. Machinery, for example, has its own rules for securing attachments and the minimum number of tiedowns. Special-purpose loads such as beams and crane booms that need special fastening methods aren't covered by the 393.110 count, but still must be "securely and adequately fastened" (393.110(d)). Oversize work brings permits too; see oversize load permits.

Common violations, and how to avoid them

1. Too few tiedowns for the length. Count before you leave the shipper.
2. WLL math done at full value for direct-attached tiedowns. Half counts.
3. Worn straps still in the rotation. Retire them.
4. No edge protection on steel, stone or sharp-cornered freight.
5. Skipped 50-mile check. It's required, and it's when most problems show up.
6. Loose tarps. A flapping tarp can loosen tiedowns and blow cargo debris.

Add securement gear to your pre-trip inspection checklist so it's checked every day, not just when a load looks tricky.