Thanks guys for all the replies, much appreciated.
.) On the new lighter TT: 2 each 2200 lb axles + 377 lb tongue weight = 4777 Gross from Flagstaff specs. Our old TT was 8450 lbs gross with 815 lb tongue. This new lighter one is about half the weight of the big one.
.) On the Burb GVWR, I did lie (not purposefully though). It is 8600 GVWR, 1997. I was told years ago by a gm friend that it was the heaviest 3/4 ton Burb available, before the 1 ton trucks starting a few hundred pounds heavier (I think he said around 9200 but can't remember positively). That 9200 lb figure stuck in my mind, sorry for the mis-info.
.) And many thanks for the 55-65 lb advice. I know the exact weighing will be best and I will get that done before any long trips, but in the meantime, I know that I'm well within Load Range D weights with that light camper and only my wife & I and cargo, so I'll look for the inflation chart and drop them a bit for now.
Thanks again to all
Edit: I found the exact inflation chart for that Michelin LT245/75R16 E tire, and it appears to me that nickthehunter and goducks10 are spot on, Many Thanks:
Single tires on axle:
50 psi: 4410 per axle (2 tires), 8,820 for 4 tires
55 psi: 4670 per axle (2 tires), 9,340 for 4 tires
60 psi: 4960 per axle (2 tires), 9,920 for 4 tires
65 psi: 5250 per axle (2 tires), 10,500 for 4 tires
70 psi: 5530 per axle (2 tires), 11,060 for 4 tires
75 psi: 5800 per axle (2 tires), 11,600 for 4 tires
80 psi: 6084 per axle (2 tires), 12,168 for 4 tires
(3042 lbs at 80 psi per tire)
So, if I'm understanding correctly,
then 8600 GVWR Burb (including 377 tongue weight) lbs
so anything 50 psi or above would be within load spec?
I would of course add a cushion, so the 55-65 psi
recommended sounds good, Thanks Again