Getting tired of spinning my tires on ice at intersections. Was thinking I could put a couple studded tires on the back of my 4 WD Frontier. I used to have some on my rear wheel drive S-10 and they worked great. I've got BF Goodrich Rugged Terrain tires on there now, and even with it in 4WD, I sit and spin before I can get going. Even have 350 pounds of sand in the box. Do I need to get 4, or can I just put 2 on the back?