Ask The RV Engineer

What’s the Difference Between Weight Distribution and Sway Control?

Weight distribution is not the same thing as sway control.

Actually, let me rephrase that, because it’s not 100% accurate.

  • The primary purpose of a weight-distribution hitch (also known as a load-leveling or equalization hitch) is to level the truck-and-trailer combination and restore some of the weight lost to the tow vehicle’s front axle.
  • The primary purpose of sway control is to reduce and damp any side-to-side oscillations while driving, particularly at highway speeds.

Somewhat confusingly, a trailer with proper weight distribution will naturally tend to sway and bounce less. This is the primary reason we have minimum tongue/pin weights, after all. But this is where, unfortunately, the English language has failed us, and this sloppy use of the phrase “weight distribution” has called all manner of confusion.

2 responses to “What’s the Difference Between Weight Distribution and Sway Control?”

  1. Jim Johnson

    Would love a discussion on electronic sway control. Our 2020 Subaru Ascent’s manual is pretty specific about not using weight distribution hitches and that the AWD system will automatically handle sway. The amazing thing is it does! I’ve seen trailers sashaying ahead of me, while ours is arrow straight. We tow a 21′ TT with a loaded weight around 3.500 and 10% hitch weight. The Ascent is rated for 5,000 and 500 hitch weight.

    Regular RV Travel reader…

    Reply
    1. Andy

      Hello Jim! I think that’s an excellent idea, but I’ll need to do more research 🙂 My rudimentary understanding of ESC is that the car’s ECU detects the onset of sway and rapidly applies and modulates the brakes to counteract the side-to-side forces. I suspect another reason the Ascent can getaway with a simple weight-carrying hitch is because the total weight of the trailer is about the same or less than the weight of the vehicle itself, therefore the Ascent has more relative mass to resist the sway forces.

      Reply

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