Decreasing trolley drift (cart: front steering)

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I've just modeled a trolley for my robot to pull around, however I can't make it stop drifting. I've added friction to the wheel joints, but it does not produce any effect.

I observe the same drift with the gazebo model 'Cart: front steering'.

The trolley is fully stopped at the beginning of the simulation, but then it starts to move. If I disable the trolley's base link gravity (only wheels remain affected by gravity), it won't move. But removing the effect of gravity on the trolley is not an acceptable solution for me.

Do you have any suggestions on how to make the trolley not drift?

Edit: After removing friction from wheel joints, the robot drifts less.

Edit2: As asked in the answer:

    <mass>5.0</mass>
    <inertia>
      <ixx>0.27</ixx>       <!-- for a box: ixx = 0.083 * mass * (y*y + z*z) -->
      <ixy>0.0</ixy>         <!-- for a box: ixy = 0 -->
      <ixz>0.0</ixz>         <!-- for a box: ixz = 0 -->
      <iyy>0.15</iyy>       <!-- for a box: iyy = 0.083 * mass * (x*x + z*z) -->
      <iyz>0.0</iyz>         <!-- for a box: iyz = 0 -->
      <izz>0.415</izz>       <!-- for a box: izz = 0.083 * mass * (x*x + y*y) -->
    </inertia>
  </inertial>

For the wheels:

  <inertial>
    <mass>0.1</mass>
    <inertia>
      <ixx>0.00001</ixx>
      <ixy>0</ixy>
      <ixz>0</ixz>
      <iyy>0.00001</iyy>
      <iyz>0</iyz>
      <izz>0.00001</izz>
    </inertia>
    <pose>0 0 0 0 0 0</pose>
  </inertial>