DOT 49 CFR 393 Cargo Securement
Subpart I of 49 CFR Part 393 governs how cargo must be secured on commercial vehicles. This page covers the parts that determine how many winches a flatbed needs and what rating they must carry.
Nothing here is legal advice, and it is not a substitute for the regulation. The authoritative text is published by FMCSA. Verify your own configuration against it.
Where a winch sits in the rule
A cargo tie-down winch is one end of a tie-down assembly. It is the anchor point and tensioning device; the strap is the tie-down; the cargo is the article being secured. The regulation does not regulate winches as a product category. It regulates the assembly and its rated capacity.
Two consequences follow. First, a winch has no compliance status on its own — only an assembly does. Second, the assembly is rated at its weakest component. A 6,600 lb winch paired with a 3,335 lb strap gives you a 3,335 lb tie-down, not a 6,600 lb one.
The sections that matter
| Section | Subject | Why it matters |
|---|---|---|
| § 393.102 | Performance criteria | Securement must withstand 0.8 g deceleration forward, 0.5 g rearward, and 0.5 g lateral. |
| § 393.104 | Device and system standards | Tie-downs, anchor points, and tensioners must be in good working order with no damage or weakening that impairs function. |
| § 393.106 | General securement rule | Contains the aggregate working load limit test in paragraph (d). |
| § 393.108 | Determining working load limit | How WLL is established, and how to treat unmarked components. |
| § 393.110 | Minimum number of tie-downs | Sets a floor on count based on article length and weight, independent of capacity. |
Test one: aggregate working load limit
§ 393.106(d) requires that the aggregate working load limit of all tie-downs securing an article be at least one half the weight of that article.
For a 20,000 lb steel coil, tie-downs must total at least 10,000 lb of working load limit. Four assemblies rated 6,600 lb give 26,400 lb aggregate, comfortably clear — assuming the straps are also rated 6,600 lb or better.
Test two: minimum number of tie-downs
§ 393.110 sets a separate floor that does not care about capacity. For an article not blocked or immobilised against forward movement:
| Article length | Article weight | Minimum tie-downs |
|---|---|---|
| 5 ft or less | 1,100 lb or less | 1 |
| 5 ft or less | more than 1,100 lb | 2 |
| Over 5 ft, up to 10 ft | any weight | 2 |
| Over 10 ft | any weight | 2, plus 1 for every additional 10 ft or fraction |
Both tests apply. This is the most common misreading of the rule. Two heavy-rated tie-downs can satisfy the aggregate calculation on a 24 ft article and still be short of the four the count rule requires.
Worked example
A 24 ft, 18,000 lb article, not blocked forward:
- Aggregate WLL: needs ≥ 9,000 lb. Two 6,600 lb assemblies give 13,200 lb. Passes.
- Count: over 10 ft, so 2 plus one per additional 10 ft or fraction. 24 ft is 10 + 14, and 14 ft is two more 10 ft increments or fractions, so 4 total. Two assemblies fails.
- Result: four tie-downs, aggregate 26,400 lb. The count rule, not capacity, sets the answer.
Commodity-specific rules
§§ 393.116 through 393.136 add requirements for particular commodities — logs, dressed lumber, metal coils, paper rolls, concrete pipe, intermodal containers, cars and light trucks, roll-on/roll-off containers, and boulders. If you haul any of these, the commodity rule governs and can require more than the general rule.
Practical checks on the winch itself
- Confirm the winch, strap, and anchor are undamaged before each trip — § 393.104 requires it.
- Rate the assembly at its lowest-rated component, not the winch.
- Ensure the tensioner holds without slipping; a winch that creeps under load is not in good working order.
- Check the lock state visually before departure. On our winches the small handwheel stands clear of the gear body when released, so it can be read at a glance.
Our winches are rated WLL 6,600 lb (3,000 kg). See WLL vs breaking strength for why that is the figure used here rather than the breaking strength, and the product range for individual models.
Common questions
- How many tie-downs does 49 CFR 393.110 require?
- One tie-down for an article 5 ft or shorter and 1,100 lb or lighter. Two tie-downs if the article is 5 ft or shorter but heavier than 1,100 lb, or if it is longer than 5 ft and up to 10 ft at any weight. For articles longer than 10 ft: two tie-downs, plus one more for every additional 10 ft of length or fraction of it.
- What is the 50 percent rule in cargo securement?
- Under 49 CFR 393.106(d), the aggregate working load limit of all tie-downs securing an article must be at least one half of the weight of that article. A 20,000 lb article therefore needs tie-downs totalling at least 10,000 lb of working load limit.
- Does the aggregate WLL test replace the minimum tie-down count?
- No. They are two independent tests and a load must pass both. Two very high capacity tie-downs can satisfy the aggregate working load limit while still failing the minimum count required by 393.110 for a long article.
- What working load limit does a cargo tie-down winch contribute?
- Its full rated working load limit, provided the winch, the strap, and the anchor point are all in good working order as required by 49 CFR 393.104. The governing figure for the assembly is the lowest rated component in the load path.