@Override
    @SuppressWarnings("unchecked")
    public void read(JmeImporter im) throws IOException {
        InputCapsule capsule = im.getCapsule(this);
        tuning = new VehicleTuning();
        tuning.frictionSlip = capsule.readFloat("frictionSlip", 10.5f);
        tuning.maxSuspensionTravelCm = capsule.readFloat("maxSuspensionTravelCm", 500f);
        tuning.maxSuspensionForce = capsule.readFloat("maxSuspensionForce", 6000f);
        tuning.suspensionCompression = capsule.readFloat("suspensionCompression", 0.83f);
        tuning.suspensionDamping = capsule.readFloat("suspensionDamping", 0.88f);
        tuning.suspensionStiffness = capsule.readFloat("suspensionStiffness", 5.88f);
        wheels = capsule.readSavableArrayList("wheelsList", new ArrayList<VehicleWheel>());
        motionState.setVehicle(this);
        super.read(im);
    }
used internally

@return the pre-existing instance
jme3-jbullet/src/main/java/com/jme3/bullet/objects/PhysicsVehicle.java