Tow Chain Buying Guide What Grade, Size, and WLL You Actually Need in 2026
Spec the wrong chain and you're either under-secured or carrying dead weight. Neither is acceptable when you're hauling a vehicle down the interstate at highway speed.
This guide covers chain grade designations, diameter-to-WLL relationships, hook and binder compatibility, and DOT transport chain requirements. Running a single rollback or managing a small fleet, here's how to buy chain that actually matches your haul.
Chain Grade: What the Number Means
Chain grade tells you the steel's tensile strength relative to its diameter. Higher grade means more working load limit in a smaller, lighter chain. The three grades you'll encounter in towing and transport are G70, G80, and G100.
Grade 70 (G70) Transport Chain
G70 is the DOT-standard grade for vehicle and cargo securement on flatbeds and car haulers. Heat-treated carbon steel, stamped with "G70" or "7" on the links, rated specifically for transport use under FMCSA securement regulations.
A 5/16-inch G70 chain carries a working load limit of 4,700 lb. A 3/8-inch G70 steps up to 6,600 lb. These are the sizes you'll see most on car hauler decks and rollback beds.
G70 is not a lifting grade. Transport securement only — never overhead lifting.
Grade 80 (G80) Chain
G80 is alloy steel rated for overhead lifting. It carries roughly 25% more WLL than G70 at the same diameter. A 3/8-inch G80 chain rates at approximately 7,100 lb WLL.
If you're rigging for a crane pick or running chain slings on a construction site, G80 is the minimum grade. Riggers who need certified slings with rated and marked specs should be looking at G80 and G120 chain slings specifically.
Grade 100 (G100) Chain
G100 is alloy steel with higher tensile strength than G80, used in lifting applications where weight savings matter. A 3/8-inch G100 chain carries approximately 8,800 lb WLL. Less common in towing and transport, but relevant for riggers working with tight weight budgets.
Chain Diameter and WLL: Quick Reference
Matching diameter to working load limit is straightforward once you know the grade. Here's what the numbers look like across common transport and lifting applications:
| Chain Size | Grade 70 WLL | Grade 80 WLL | Grade 100 WLL |
|---|---|---|---|
| 1/4 inch | 3,150 lb | 3,500 lb | 4,300 lb |
| 5/16 inch | 4,700 lb | 4,500 lb | 5,700 lb |
| 3/8 inch | 6,600 lb | 7,100 lb | 8,800 lb |
| 1/2 inch | 11,300 lb | 12,000 lb | 15,000 lb |
Note: G80 at 5/16 inch rates slightly lower than G70 at the same diameter in some configurations because G70 is optimized specifically for transport loads. Always verify the rated WLL stamped on the chain or listed on the product spec sheet.
DOT Transport Chain Requirements
Under FMCSA cargo securement rules (49 CFR Part 393), chains used to secure vehicles and cargo must meet specific aggregate WLL requirements based on load weight.
The key rules:
- Each tiedown must be attached and secured to prevent cargo from shifting
- The aggregate WLL of all tiedowns must equal at least half the weight of the cargo being secured
- For vehicle transport, the number of tiedowns required depends on vehicle length and weight
G70 is the DOT-specified grade for transport chain. Ungraded chain or consumer-grade hardware doesn't meet these requirements. If a chain isn't stamped with its grade and WLL, it doesn't belong on a commercial haul.
Hook and Binder Compatibility
Chain is only as good as its end fittings. Get the hook or binder wrong and you've introduced a weak point regardless of what the chain itself is rated for.
Grab Hooks vs. Clevis Hooks
Grab hooks seat the chain link directly in the hook throat. They're the standard fitting for transport chain because they lock the chain at a specific length without slipping. Clevis hooks are more versatile but less common in chain-to-axle applications.
Your hook's WLL needs to match or exceed the chain's WLL. A 4,700 lb chain paired with a 3,500 lb hook is a 3,500 lb system — the chain rating doesn't matter if the hook fails first.
Load Binders
A ratchet-style load binder rated 7,100 lb SWL, compatible with 5/16-inch or 3/8-inch Grade 70 chain, covers both common transport chain sizes without carrying two different binders. Ratchet binders apply tension incrementally and hold it without the snap-back risk of lever binders.
Match binder WLL to chain WLL. Don't run a 3/8-inch G70 chain rated 6,600 lb through a binder rated for 4,700 lb.
Sizing Chain for Your Haul
Car Haulers and Rollbacks
Most passenger vehicles and light trucks fall in the 3,000 to 7,000 lb range. Four 5/16-inch G70 transport chains rated 4,700 lb SWL each gives you an aggregate WLL of 18,800 lb across your tiedown points — enough to cover the vast majority of vehicle transport loads.
For heavier vehicles — full-size trucks, SUVs, work vehicles — step up to 3/8-inch G70 at 6,600 lb per chain.
Flatbed and Cargo Securement
Flatbed cargo securement typically starts at 3/8-inch G70. For heavy equipment transport, you may need 1/2-inch G70 or G80 depending on load weight and available tiedown points.
Calculate your aggregate WLL requirement first: total load weight divided by two equals the minimum aggregate WLL you need across all chains and tiedowns.
Lifting Applications
Using chain for lifting rather than transport? Switch to G80 or G100. G70 is not rated for overhead lifting and should never be used in a sling configuration above a load.What to Look for When Buying Tow Chain
A few things that separate professional-grade chain from hardware that will fail you mid-haul:
Grade stamp on every link. G70 chain should have "G70" or "7" heat-stamped directly on the links. No stamp means no traceable rating.
Rated and marked WLL. The product listing should state the working load limit explicitly — not "heavy duty" or "high strength."
Proof-coated or yellow chromate finish. G70 transport chain typically comes with a yellow chromate finish for corrosion resistance and easy visual identification.
Hook WLL that matches the chain. Confirm hooks and binders are rated to match the chain, not just listed as "compatible" without a number behind it.
Consumer-grade chain sold at mass-market retailers often carries no grade stamp and no rated WLL. It may look like G70, but it's not manufactured to the same tensile strength standard. On a commercial haul, that's a liability you don't need.
Chains and Binders Together
Buying chain and binders separately and hoping they match is a common mistake. Spec the chain size first, then buy binders rated for that chain.
A ratchet load binder compatible with both 5/16-inch and 3/8-inch G70 chain covers the two most common transport chain sizes in a single tool. That matters when you're running mixed loads or stocking a small fleet with one binder type across the board.
At Vulcan Brands, the catalog includes G70 transport chain, rated ratchet binders, axle straps, hooks, and car hauler chains in one place. Every order ships free with no minimum. Fleet operators can set up an account and reorder their standard chain and binder setup without re-entering specs each time.
Frequently Asked Questions
What chain grade is required for vehicle transport? Grade 70 (G70) is the DOT-specified grade for cargo and vehicle securement under FMCSA regulations. It must be stamped with the grade designation and carry a rated WLL. G70 is not approved for overhead lifting.
What is the WLL of a 5/16-inch G70 transport chain? A 5/16-inch G70 chain carries a working load limit of 4,700 lb. For heavier vehicles, step up to 3/8-inch G70 at 6,600 lb WLL.
Can I use G70 chain for lifting? No. G70 is rated for transport securement only. Overhead lifting requires G80 at minimum. Using G70 in a lifting sling configuration is outside its rated application and creates serious safety risk.
How many chains do I need to secure a passenger vehicle? FMCSA rules require at least four tiedowns for most vehicle transport applications. The aggregate WLL of all tiedowns must equal at least half the vehicle's weight. Four 5/16-inch G70 chains give you 18,800 lb aggregate WLL, which covers most passenger vehicles and light trucks.
What size load binder works with G70 transport chain? A ratchet-style load binder rated for 5/16-inch or 3/8-inch Grade 70 chain covers both common transport chain sizes. Confirm the binder's WLL matches or exceeds the chain's WLL. A 7,100 lb rated binder works with both 5/16-inch and 3/8-inch G70.
What is the difference between a grab hook and a clevis hook on transport chain? A grab hook seats the chain link in the throat and holds the chain at a fixed length — that's why it's the standard for vehicle transport tiedowns. A clevis hook connects to a fixed point like a ring or anchor and is more versatile but less suited to direct chain-to-axle applications.
How do I know if chain I already own is rated for transport? Look for a grade stamp directly on the links. G70 chain is stamped "G70" or "7." No stamp, no rated WLL on the packaging, no documentation of the grade — treat it as unrated and keep it off a commercial haul.
Spec the right grade, match your binders to your chain size, and verify the WLL before the load goes on the deck. Browse the full tow chain and cargo control catalog at vulcanbrands.com — everything ships free, no minimum required.