I agree with Stuart and CuNmUd, those tires are rated for more than enough to safely carry your truck. Load ranges can be misleading, at the end of the day the weight rating of the tire is what determines whether or not it's safe to mount.

Make sure to NOT exceed 35 PSI with those things though. You have a much wider footprint than the stock size, so they don't need nearly as much pressure as stock tires to carry the same weight.