I believe he was referring to dual wheels verses super singles, although you’re right. Bad pavement is fun with a wiggle wagon.
I am having a similar problem as OP, which is why I looked up this thread. I've been driving 1.5 years but I came from LTL doing sets of pups (and not that heavy) and now I'm all van 70k and up. CAT Scale ticket: Steer 11440 Drive 28860 Trailer 30320 Gross 70620 So I'm "only" 1460 heavier on the tandems...I saw the difference when I scaled but didn't think it would make too much difference. Well. I had about 4 gusts of wind today coming through western PA and I was more worried about how she was handling than with 22k in the box in 40mph sustained winds on 80E in WY two weeks ago... It's been handling poorly out the gate since I picked it up yesterday. I cannot inspect the load configuration as it was preloaded and sealed. 5th wheel is freshly greased. Tandems are set maybe 2-3 holes longer than California legal. Do you think that 1460 extra on the tandems would really make such a marked difference in handling?
That seems pretty evenly spread to me. Do you have room to legally slide the trailer tandem back a few notches to experiment?