What is the change in the coefficient of friction for a waxed and unwaxed board then?
I don't know the answer to that but I can tell you it completely depends on the condition and is going to vary greatly based on the conditions. I can also tell you I've nose dived hard off of a booter first shot over the handle bars cause my board stuck to the snow. With out wax I'lll pick my board up and it will have a foot of snow stuck to it like Velcro. You get those wet hot sticky left over spring conditions, no wax= brakes, Wax= HorsePower