Ultradynamico ROSÉ JFFThe ROS is the first offering and the mainstay of Ultradynamico's line. Double it up for optimal traction offroad or pair it with a CAVA in the rear to drift the corners a bit more. JFF means Just For Fun, but not ONLY for fun these tires are equally equipped for long days locked in the pain dungeon as they are for a Sunday tour of Portland's vegan doughnut shoppes. JFF is our most accessible offering; think of it as the industry standard in terms of