The tires are like the ones the racers use on ice round tracks. They have screws coming from the inside. Talk about having some balls, they race dirt track style racing on ice with spikes in their tires, how would you like somebody sliding into you!
They aren't just riding for pleasure. That's a school people can go to and ride that Gixxer, 'Busa and one other, more newbie friendly steed. I wish I could remember which issue it was in, as I never throw anything away.