Yea, way over pressurized but they drove better that way so I was in no hurry to find the "correct" pressure. Chalk looks doable so I'll give it a try and post results. LT265/75 R16 Service is 123/120R for a max load of 3415 @ 80psi & 106mph
Chalk does reveal best contact between 40 & 50 psi. Process takes a while with test drives and all. Chalk showed about the best at 50 but looked the same at 40. Test drive @ 40 not that bad but need to check at 50. I suspect that tires would need to be really low to show "cupping".