I saw a guy where I live (in Buffalo, NY) riding a dirt bike on an iced-over pond. I was skiing past and he told me he uses studded tires to grip the ice. He went around and around this little pond and never dumped the bike. The studded tires seemed to work pretty well. He towed his bike there on a sled pulled by his snowmobile. Some people won't let the Winter defeat them. For my part, I'll be working on my bike in the garage with a portable heater nearby.