My tires run when I am towing at about 98% capacity ...
What most are missing is the fact that when ANYONE puts a capacity on something, that does NOT mean that as you get close, you shouldn't do it...
It simply means that whatever is being rated has been tested to perform at that particular weight.. safely under proper conditions.
If an overhead crane is rated at 3 ton, you can lift 3 ton all day, everyday and as long as you don't abuse the equipment, your good to go.
My big trucks are rated at 80,000# ... we run at that weight almost daily
I look at tires the same way...
*** DISCLAIMER *** It is Just my opinion on the subject.....