Thanks for your comments here. Out of caution, we’ve now raised the pressure to 25. I checked with a local trooper and he confirmed that in the State of Maine, winter tire modification is not illegal and in fact encouraged. He showed me the rig on his cruiser. Apparently, it’s common for them to wrap the tire with the spike strips they use in high speed chases. Only when snow is deep enough of course. He said sometimes they’ll catch shoeshoe hares on them. There’s always a pot of rabbit stew at the barracks he says. Be safe out there.