Why RV stabilizer extension matters more than you think

When it comes to RV stabilizers, there’s a common thread among many RVers: The less you crank them down, the more stable they are. You’ve probably driven through campgrounds and seen how much blocking people stuff under their stabilizers—only to crank them down an inch or two. Good idea? Not according to physics. RV stabilizers have a sweet spot: Crank them down too little, or too much, and they don’t do their job.

Get those RV stabilizers down in a hurry?

When you pull into your campsite and start setting up, it’s tempting to get the stabilizer jacks down quickly and call it good. But how far you extend your jacks can make a big difference in how stable—and comfortable—your RV will be. Go too short, and the rig may still wobble. Go too far, it can be the same or worse: You might damage the jacks or your frame.

While it might seem like a minor detail, several manufacturers and RV experts suggest there’s a “sweet spot” for stabilizer jack extension. And it turns out that extending the jacks to around 60% to 70% of their full range can offer the most effective support.

What the manufacturers say

Let’s start with what’s actually written in the manuals—when it’s written at all.

Lippert™ Components
Lippert, one of the largest suppliers of RV jacks and chassis components, doesn’t provide a specific extension percentage. However, its manuals stress one key point: Stabilizer jacks are not meant for lifting or leveling, only for minimizing movement once your RV is already level. They also warn against overextending or using the jacks on unlevel ground without proper support, which can twist the frame or cause jack failure.

BAL^® (Norco Industries)
BAL’s stabilizer products, like the popular “C-Jack” and telescoping models, similarly don’t cite an ideal extension percentage. But user experience and aftermarket support strongly suggest that more extension equals more stability, so long as you’re not exceeding the jack’s designed range. Their triangular geometry becomes more effective as they extend, especially for side-to-side stability.

Hubbell (and generic scissor jacks)

Some aftermarket jack models sold under Hubbell or white-label brands have clearer guidance. One scissor jack model rated for 5,000 pounds clearly states that it reaches full rated strength only when extended between 13 3/4″ and 23 1/2″—a range that represents roughly 60% to 98% of its full stroke. Any less than that, and the strength (and stability) is “drastically reduced.” (pdf)

Why 60–70% extension works

The geometry of most stabilizer jacks—especially scissor or telescoping types—means they become more rigid and better at resisting motion the farther they extend. At minimal extension, the angle of support is too shallow to be effective, and the jacks can flex more easily.

By extending into the 60–70% range:

• You get better triangulation for side-to-side and front-to-back support.
• The jacks engage more of their structural strength.
• Movement inside the RV—walking or bouncing—and wind translates into less visible shake.

Triangulation? What’s that all about?

In this context, triangulation refers to how the stabilizer jack forms a triangle-like support structure with the RV frame and the ground. The more effective the triangle, the more rigid the support — which minimizes wobble.

Think of your RV as the top side of a triangle. The stabilizer jack acts as the angled leg. The ground is the base. When a stabilizer jack is extended properly—say, 60–70% of its travel—it creates a longer diagonal and a wider angle with the ground. This forms a broad, supportive triangle that resists lateral and vertical forces.

Check out this illustration showing a “stab jack” and you can see the difference in too little, too much, and “just right.”

But what about scissor jacks? Is the triangulation business important here?

Scissor jack stabilizers operate on the same fundamental principles of triangulation as other stabilizer types and, in fact, these mechanics are especially critical to their performance. As the jack extends, its arms form an angled, X-shaped brace between the RV and the ground. This diagonal configuration creates a triangle-like structure that resists movement and provides support.

The farther the jack is extended—within a safe operating range—the more effective this triangulated structure becomes. Most scissor jacks perform best when extended to approximately 60 to 70 percent of their total travel. At this range, the angle between the RV frame and the ground is wide enough to offer real resistance to lateral movement caused by walking, wind, or shifting weight.

If the jack is barely extended, it remains nearly vertical and lacks the side-to-side bracing necessary for stability. Conversely, if it’s extended too far, the arms flatten, the triangle becomes too shallow, and the jack can lose strength or even buckle under pressure.

Many manufacturers warn that full weight capacity is only available within a certain mid-range of extension, and going outside of that—either too short or too long—reduces structural integrity. To stay within the ideal range, it’s best practice to use base blocks or jack pads beneath each foot. This reduces the amount of crank-down needed and helps the jack remain in its strongest position. But don’t go overboard! Keep the blocking to the point where you can still crank down the stabilizer to that 60–70% sweet spot.

With any stabilizer jack, be sure not to extend all the way out unless absolutely necessary, as the final 10% of travel can be less stable and more vulnerable to bending or damage, especially on uneven ground.

Best practices for RV stabilizers

To get the most out of your stabilizers (and avoid damage), follow these field-tested tips:

Level first, stabilize second
Stabilizer jacks are not leveling tools. Use leveling blocks to get the RV level before lowering your stabilizers.

Extend to the right height
Aim to extend your stabilizer jacks to about 60–70% of their full travel. If your jacks max out at 24″, shoot for at least 14″ of extension. This puts you in the “strong zone.”

Use jack pads or blocks properly
If the ground is uneven or too low, place blocks or jack pads under each foot. This lets you reach that ideal extension range without maxing out the jack.

Tighten evenly—but not too hard
Crank each jack until it’s snug and firm. Don’t keep cranking in an attempt to lift the RV—that’s a job for your leveling gear.

Final thoughts

While your owner’s manual might not give a specific number, field data and at least one scissor jack manufacturer clearly show that stabilizers perform best when extended 60–70% of their range. Less than that, and you’re just touching the ground; more than that, and you may be stressing the equipment.

A little math and a few blocks can go a long way toward a shake–free RV setup. Your feet—and your coffee cup—will thank you.

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