Well GoPackGo is correct. I verified that the new goodyear endurance is rated for single and dually configuration and the 117/112 refers to the load index single vs. dual. So the 225/75-15 LRE is rated to carry the 2830lbs like other E ST tires but at 87mph.
So, at least spec wise the goodyears are IMHO at the top of the heap for ST tires. I know of no other ST tire in that size with that speed rating AND Load index.
And actually similar specs to many of the LT tires but a higher load index for the same size tire. Many of which have an N or Q (99mph) rating.
Interestingly my Denali has S (112) rated LRE tires but speed limiter is set lower than that, 99.