What’s the Difference between Direct and Indirect Tiedowns?
If you’re hauling on a flatbed, your tie-down work is on display for everyone on the road, including DOT roadside inspectors. How you secure your load says everything about whether you know what you're doing, and getting it wrong can cost you a shifted load, failed inspection, or worse.
Two things separate the pro haulers: knowing when to use a direct tie-down vs. an indirect one and understanding how to calculate your aggregate working load limit (WLL). Get both right, and you're sure to be both safe and compliant on the road. Here's how they work.
What is a Direct Tie-Down?
A direct tie-down runs straight from an anchor point on your trailer to the cargo itself. One end is attached directly to the load, and the other is attached to the trailer. It's the simplest setup, but it comes with a trade-off: because the tension is pulled in one direction, a direct tie-down only uses half its rated WLL toward securing the load.
What is an Indirect Tie Down?
An indirect tie-down goes up and over (or through) the cargo, connecting to anchor points on opposite sides of the trailer. Because the strap works against the cargo from both sides at once, it contributes 100% of its WLL toward securement.
Should You Use a Direct or Indirect Tie-Down?
That depends on the cargo. Bulky, irregular, or oddly shaped loads often need a mix of both methods for securement. The FMCSA's cargo securement rules set the baseline requirements, but the short version is that your straps or chains need to hold the cargo in place no matter what the road throws at you.
Check out our dos and don’ts for cargo securement to learn more.
How To Calculate Aggregate Working Load Limit
The aggregate WLL is the total securing power of every strap, chain, or binder holding the load in place. The FMCSA states: “The aggregate working load limit of any securement system used to secure an article or group of articles against movement must be at least one-half the weight of the article or group of articles.”
Here's how to get there:
- Direct tie-downs count for 50% of their rated WLL.
- Indirect tie-downs count for 100% of their rated WLL.
Add those figures across every strap in your system. If the total meets or exceeds half your cargo's weight, you're compliant. If it doesn't, add more tie-downs or use tie-downs with a higher WLL.
Aggregate WLL Example
Say you're hauling a 10,000 lb. piece of equipment. You'll need at least 5,000 lbs of aggregate WLL. Four direct tie-downs rated at 3,333 lbs each would give you 6,666 lbs toward that total (half of 13,332). That's enough to meet the requirement.
Need help figuring out exactly how many straps your load requires? Our guide on how many tie-down straps you need breaks it down by cargo length and weight.
Tie-Down Straps from US Cargo Control
To ensure safe transport for both your cargo and your staff, we tested all of our ratchet straps for safe use and labeled them with working load limit (WLL) information. Most also meet requirements/guidelines from several key authorities:
- Commercial Vehicle Safety Alliance (CVSA)
- Department of Transportation (DOT)
- Web Sling & Tie Down Association (WSTDA)
- North American Cargo Securement
If you don’t see what you’re looking for, we can create custom ratchet straps for you. Whether you need one simple assembly or multiple intricate configurations, we can use any combination of strap size and fittings to create the perfect tie-down solution. Just fill out our form or call one of our product experts at 866-444-9990 to learn more!
More Trucking Equipment from US Cargo Control
If you need additional trucking equipment, we have everything you need to outfit your truck. From heavy-duty tarps, corner protectors, and transport chain and binders, we'll make sure to get you what you want, when you need it. Start by shopping by trailer type.
Other reads on Cargo Securement and Tiedowns:
A Comprehensive Guide to Ratchet Straps
How to Care for Ratchet Straps
What are Ratchet Straps Made of?
How US Cargo Control Creates High Quality Custom Ratchet Straps
