public void setFrictionSlip(float frictionSlip) {
        tuning.frictionSlip = frictionSlip;
    }
Use before adding wheels, this is the default used when adding wheels.
After adding the wheel, use direct wheel access.<br>
The coefficient of friction between the tyre and the ground.
Should be about 0.8 for realistic cars, but can be increased for better handling.
Set large (10000.0) for kart racers.
@param frictionSlip the frictionSlip to set
jme3-jbullet/src/main/java/com/jme3/bullet/objects/PhysicsVehicle.java