Why Does the Factory Power Tailgate Malfunction After an Armored Upgrade?

A factory power tailgate is designed around the original tailgate weight, center of gravity, hinge geometry and actuator force.

After ballistic armor is added, these conditions change significantly. The original electric struts may no longer be able to open, hold or close the reinforced tailgate reliably.

The Short Answer

A factory power tailgate may malfunction after an armored upgrade because the added ballistic materials increase the tailgate weight and force requirements beyond the operating capacity of the original power liftgate system.

Using one armored Volvo XC60 project as an example, the reinforced tailgate gained approximately 50 kg after bulletproof plates were installed.

The required force values increased to:

These values are based on a specific vehicle configuration and measurement method. They should not be treated as universal specifications for every armored Volvo XC60.

Root Cause 1: Additional Tailgate Weight

Ballistic plates, reinforced glass and structural protection materials add significant mass to the tailgate.

In this Volvo XC60 example, the tailgate gained approximately 50 kg after armor installation. This additional weight increases the load on:

• Electric struts

• Hinges

• Mounting brackets

• Tailgate frame

• Latch system

• Vehicle body attachment points

The problem is not only weight. The position of the added armor also changes the center of gravity, increasing torque around the hinge axis.

Root Cause 2: F1/F2 Force Mismatch

The original factory electric struts were designed for the standard tailgate.

After armor installation, the required F1/F2 values became much higher than the OEM strut rating.

In this project:

• Required F1: 970 N

• OEM F1: 600 N

• Required F2: 2,310 N

• OEM F2: 1,430 N

This force gap means the original struts may not provide enough thrust to lift or hold the heavier armored tailgate.

(https://www.youtube.com/embed/JBjwG-grPns?si=slyj8I3103owMA2C)

Root Cause 3: OEM Components Are Not Designed for Armored Loads

When the factory struts operate beyond their intended load range, several problems may appear:

• Tailgate sagging

• Weak lifting performance

• Slow or interrupted movement

• Failure to hold position

• Motor overload

• Gear or transmission wear

• Strut pressure loss

• Hinge or bracket deformation

• Incorrect anti-pinch response

Simply recalibrating the factory system usually cannot solve a mechanical load mismatch.

Why Stronger Struts Alone Are Not Always Enough

A heavy-duty electric tailgate strut must be matched to the complete armored tailgate system.

If the thrust is increased without checking the structure, the higher force may transfer stress to the hinges, mounting brackets or tailgate frame.

A professional redesign should evaluate:

• Modified tailgate weight

• Armor material and weight distribution

• Tailgate center of gravity

• Required F1/F2 force values

• Actuator mounting angle

• Hinge and bracket strength

• Motor torque and working current

• Transmission component size

• Anti-pinch and obstacle detection

• Manual emergency operation

Technical Solution: Customized Heavy-Duty Electric Tailgate Struts

For armored SUV projects, the electric tailgate system often needs a customized heavy-duty solution.

This may include:

• Higher-force electric struts

• Higher-torque drive units

• Reinforced internal transmission parts

• Stronger mounting brackets

• Optimized spring force

• Revised controller parameters

• Vehicle-level cycle testing

• Hold-position and safety validation

The final specification should be based on measured vehicle data and complete-system testing rather than tailgate weight alone.

Conclusion

An armored upgrade changes the mechanical load, force requirement and safety behavior of the factory power tailgate.

In the Volvo XC60 example, the reinforced tailgate required significantly higher F1/F2 force than the original factory electric struts could provide.

For armored, modified and heavy-duty vehicles, a reliable power tailgate solution must be engineered as a complete system, including actuator force, structural strength, movement control and safety validation.

TOMASTER develops customized heavy-duty electric tailgate struts and power liftgate systems for armored SUVs, modified vehicles and professional vehicle applications worldwide.