Inner vs. Outer Rocker Panels

The inner and outer rocker panels are crucial components of your vehicle, welded together to support its strength, safety and handling. These panels are also an essential barrier against road salt, debris and moisture.

Failing to replace damaged or overly worn rocker panels can cause corrosion and weaken your vehicle’s core, leading to potential hazards. Replacing them as needed is key to keeping your ride safe and protecting its value.

If it’s time to replace your panels, you’ll need to know the differences between each one and whether you should replace one or both.

Key Differences Between Inner and Outer Rocker Panels

Inner and outer rocker panels serve slightly different purposes, and understanding each type is key to successfully navigating your repair or replacement project. When comparing inner versus outer rocker panels, note the following main differences:

Position and Function

Also referred to as a rocker or rocker molding, a rocker panel is a long strip of metal that extends horizontally across the sides of a vehicle below the doors. An inner rocker panel is located behind the outer rocker panel but is still part of the cab/cabin. In comparison, the outer rocker panel is situated on the vehicle’s exterior between the front and rear wheel wells, also below the doors.

A distinct difference in each panel’s function is that the outer rocker panels are considered the more structural rocker panels, as they’re fundamental for the vehicle’s structural integrity. Without outer rocker panels, the “box” that is your vehicle’s body would be incomplete and much weaker, especially in the event of a collision. This strong connection between both ends of your vehicle also improves vehicle handling by reducing chassis flex.

These panels:

• Keep doors aligned.
• Support the floor and middle of the vehicle.
• Provide rigid vehicle stability.
• Add overall strength.
• Keep out dirt, debris and other exterior contaminants.

Together, the inner and outer rocker panels provide even stronger structural support. With sturdy rocker panels, your vehicle is safer and better protected.

Repair and Maintenance

Due to their location, inner and outer rocker panels are prone to rust and corrosion. Keep your vehicle’s rocker panels as clean as possible, paying close attention to the outer rocker panels during regular car washes. Using compressed air and a corrosion protection product can be suitable for inner rocker panels.

If either panel experiences significant rust, it becomes a safety issue, as the vehicle’s body integrity is compromised. Although both panels serve different functions, you should replace either or both when corrosion is present. If a replacement is necessary, you’ll need to remove the old panels, clean the area properly and install the right replacement options.

Some trucks have three rocker panels — the inner, middle and outer. For example, General Motors trucks made from 1999-2006 have a middle panel. Most often, it’s only necessary to replace the inner and outer panels when they show signs of wear.

How Inner and Outer Rocker Panels Work Together

Each rocker panel plays a different role in protecting your vehicle. However, they also work together to maintain vehicle balance and functionality. These panels provide an essential connection point at the front and rear of the vehicle — in the event of a collision, both panels can absorb and distribute the energy of the impact.

The outer panel provides essential structural support, but it can also be seen as a protective guard. With the outer panel enhancing strength and acting as a shield against exterior contaminants, the inner panel is better covered from damage and can provide even more necessary strength and rigidity.

Which Rocker Panels Do You Need to Replace?

A damaged rocker panel often necessitates a replacement. A rusted, cracked or broken component — especially an outer rocker panel — can reduce vehicle structural integrity and reduce collision protection. It can also cause misaligned doors, decrease floor support and weaken the vehicle’s frame.

The rocker panel’s condition will directly impact whether you need to replace it. If you notice your outer rocker panel shows signs of rust and other damage, it’s worth inspecting the inner rocker panel, too, as rust can spread. Based on the amount of rust you find, you may be able to treat the rust with a primer and fill any rust holes with spray foam and sanding.

More extensive rust — as well as the presence of cracks and dents — will require a complete replacement. Inspect both panels and then determine whether you need to replace one or both. A worn outer rocker panel is more concerning because of its role in vehicle support and stability, but it’s also crucial to make sure your inner panel is in good condition, as both work together to support the entire vehicle.

Types of Rocker Panel Replacements

There are two main types of rocker panels:

• Welded rocker panels: These are also called full, weld-on or original equipment manufacturer (OEM)-style rocker panels. They are welded to the body of a vehicle. These are commonly inner rocker panels, though you can also weld outer rocker panels to the side of your vehicle — this process can be lengthy, but it helps achieve a proper, secure fit.
• Slip-on rocker panels: Alternatively, you can use an adhesive or fastener to attach a slip-on outer rocker panel to your vehicle. These panels are easier to install than welded panels. Still, they require preparation to remove rust and drill holes.

Select your rocker panel replacement part based on which panel you’re replacing and the type of work you’re comfortable completing. The replacement panel should fit tightly, with no gaps or misalignment. If installing an outer rocker panel, seal the seams to keep out moisture and paint over the final product to protect against rust.

Shop Rocker Panels From Raybuck Auto Body Parts

No matter what kind of work you’re completing on your vehicle, you want to be able to access high-quality parts from a trusted source. Since 1985, Raybuck Auto Body Parts has provided customers with a wide array of parts for various makes and models, plus expert customer service. Along with our large inventory of inner and outer rocker panels, we offer vehicle body parts, lights, engines, fuel tanks and much more.

Shop our selection of rocker panels today, or reach out to us with questions.