Weight Distribution Hitches: Do You Need One?
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When you couple a heavy trailer, its tongue weight pushes down behind your rear axle. The back of the vehicle sinks, the front rises, and the front wheels lose grip. A weight distribution (WD) hitch uses spring bars to push some of that weight forward to the front axle and back to the trailer axles.
Signs you need one
- The rear of the tow vehicle sags noticeably when you couple up.
- The front end feels light — vague steering, weaker braking.
- Headlights aim upward at night.
- The trailer sways or fishtails at highway speed.
- Your owner's manual calls for one above a certain trailer weight — many do, so check yours.
Round bars vs trunnion bars
| Round spring bars | Trunnion spring bars | |
|---|---|---|
| Shape | Curved, slide into the bottom of the head | Straight, pivot from the side of the head |
| Capacity | Light to medium loads | Heavier loads — CURT's heavy-duty models go up to 15,000 lb |
| Ground clearance | Lower | Better |
| Cost | Usually lower | Usually higher |
Sway control: built in or added on
- Integrated sway control is built into the hitch head or bar design, with no extra parts.
- Add-on sway control, such as a friction bar, bolts on separately and adds a step when you hook up.
Weight distribution and sway control aren't the same thing: a WD hitch levels the load, and sway control resists the trailer swinging side to side. For big trailers on open highway you usually want both — see how to prevent trailer sway.
How to size a WD hitch
- Know your loaded gross trailer weight and tongue weight (how to measure it).
- Choose a hitch whose tongue weight range covers your real tongue weight. Bars far too stiff for a light tongue give a harsh ride and don't distribute properly.
- Stay within your vehicle's and receiver's ratings — a WD hitch doesn't raise your vehicle's towing capacity.
- Most WD hitches need a 2" or larger receiver — see receiver sizes.
Setup — shank height, head tilt and bar tension — makes a big difference. Follow the manufacturer's measuring procedure exactly. Browse weight distribution hitches.
Bar types and capacity: CURT — How to choose a weight distribution hitch, checked September 2026.