This may sound pretty basic......but I'm wondering how you determine axle rating (5K vs 6K) on a trailer? If looking at a manufacturer's website and they don't list that for a particular fifth-wheel...
How many lug nuts per wheel? Tell us more about the trailer. 5K is usually 5200 pound axles, and will have 6 lug nuts. 6K axles could have 6 or 8 lug nuts. Chris