Right - want to have some extra capacity for sure - what truck do you have atm?Agree with Fish and Gizmo here for a 16,000lb trailer. My truck has a max cap of 27,000 on goose neck hitch, but I would never tow that much. And with the added weight on a 5th wheel hitch (4,000 lbs ?) I‘d want duals to distribute the weight and avoid tire failures regardless of what the specs say. I’ve always advised against towing to your max capacity and having witnessed many tire failures on 5th wheels, my feeling is it’s best to have extra capacity.