Shipbucket

Because roads are not free standing like bridges the gross weight is not important but the ground pressure. You can have a very heavy tank like a Tiger or Abrams but if you have a large track area and the multiple road wheels to even out the pressure on the track then you can actually have less effect on a road than a lighter tank that may not have as much track area. The Tigers look like they have very big track areas so might have low ground pressures. Of course it doesn't matter how low your ground pressure is if you drive out onto a bridge that can't take the gross weight it is going to fall under you.