Dan,
Recently had an opportunity to pick up a set of 17.5” wheels at a great price and just ordered tires to match. I was thinking of going to the 125 psi for the full weight rating. But according to what you’re saying. At 110 psi and the 4100 pounds of capacity, it would still be a significant upgrade from my 16” Goodyear G614s.
Exactly Jamie. With weight fairly equally distributed, each of my tires is carrying about 3200 lbs. Inflating for 4100 lbs gives me a 28% margin (4100-3200 = 900 lbs margin, or 900/3200 = 28%). If ever unequally distributed, as with my first weigh-in, one tire could be carrying 3450 lbs, which would still leave a margin of 19%.
At my first weigh-in, the tire carrying 3450 was 300 lbs under the max capacity of the G614, leaving only 8% margin at full inflation.
If I inflated to 125 psi, for capacity of 4805 lbs, with actual weight of 3250 lbs, I think I might end up with uneven tread wear.
My opinion, speaking as a consumer, not as a tire expert, is that the minimum 20% margin that's required on passenger car and LT tire ratings, has a lot to do with why we don't have a lot of blowouts on those vehicles.