I have a set of these tires as well. I haven't been able to test them on the dirt much, but I know that they are probably the worst onroad tires you can get!
They are as unstable as a ballooning tire... when they aren't ballooning. They don't balloon too much as far as I could tell, but I couldn't even get to full speed with them on with the short street in front of my house. Good to know that they work well in the dirt!