Newmar tested them a few years ago, they still use the tried and true doubles.
I see a lot of them on construction and oil tanker trailers around here but almost never on the tractor unit. Must be a reason.
2009 45' Magna 630 w/Cummins ISX 650 HP/1950 Lbs Ft, HWH Active Air
Charter Good Sam Lifetime Member, FMCA,
RV'ing since 1957, NRA Benefactor Life, towing '21 Jeep JLU Rubicon Ecodiesel