How to Choose the Right Chain Size for Flatbed Cargo Securement
How to Choose the Right Chain Size for Flatbed Cargo Securement
Choosing the right transport chain isn’t just a matter of preference — it’s a matter of safety, DOT compliance, and protecting your load. When hauling machinery, steel, or equipment, the chain you choose must meet FMCSA Working Load Limit (WLL) requirements.
This guide focuses specifically on Grade 70 (G70) transport chain — the DOT-approved standard for flatbed cargo securement.
Why Chain Size Matters
Transport chain size determines its Working Load Limit (WLL). Under FMCSA rules, the combined WLL of your chains must equal at least 50% of the cargo’s weight.
Common Grade 70 Chain Sizes (Transport Chain)
These are the most commonly used G70 transport chain sizes on flatbeds. Always verify the manufacturer’s tag and markings.
| Chain Size | Grade | WLL (G70) | Typical Uses |
|---|---|---|---|
| 5/16" | Grade 70 | 4,700 lbs | General freight, light machinery, pallets |
| 3/8" | Grade 70 | 6,600 lbs | Steel, skid steers, mid-size equipment |
| 1/2" | Grade 70 | 11,300 lbs | Heavy machinery, large equipment |
How Many Chains Do You Need?
FMCSA requires the combined WLL of all chains to equal at least 50% of the cargo weight.
A 20,000 lb machine requires a minimum combined WLL of 10,000 lbs.
- Two 3/8" G70 chains = 13,200 lbs ✔
- Two 5/16" G70 chains = 9,400 lbs ✘
- Three 5/16" G70 chains = 14,100 lbs ✔
Which G70 Chain Size Should You Use?
5/16" G70
- General freight
- Lighter machinery
- Loads under ~20,000 lbs
3/8" G70
- Most common flatbed size
- Machinery & steel
- Extra safety margin
1/2" G70
- Heavy machinery
- Large equipment
- High-WLL applications
Matching G70 Chains to Binders
- 5/16"–3/8" binders → 5/16" or 3/8" G70 chain
- 3/8"–1/2" binders → 3/8" or 1/2" G70 chain
The binder’s WLL must always meet or exceed the chain’s WLL.
Common Mistakes to Avoid
- Using too few chains
- Ignoring WLL math
- Using chain with missing ID tags
- Mixing transport and lifting chain
- Choosing chain by feel instead of rating
Need Help Choosing the Right G70 Chain?
Northgate Cargo Control stocks DOT-approved Grade 70 transport chain in all common sizes. Our team can help you match the right chain and binder setup for your load.
Browse G70 Transport Chain