C# - DataGridView can't add row?

I have a simple C# Windows Forms application which should display a DataGridView. As DataBinding I used an Object (selected a class called Car) and this is what it looks like:

class Car
{
    public string color { get; set ; }
    public int maxspeed { get; set; }

    public Car (string color, int maxspeed) {
        this.color = color;
        this.maxspeed = maxspeed;
    }
}

However, when I set the DataGridView property AllowUserToAddRows to true, there is still no little * which allows me to add rows.

Someone suggested to set carBindingSource.AllowAdd to true, however, when I do that, I get a MissingMethodException which says my constructor could not be found.