RKOCH said:
Federal DOT weight in the US is 80,000 is it not? Reguardless of number of axles.
Not at all. That is the "standard" weight. Add axles, pay hundreds of dollars in permits you can move any thing you want to.
Or pay for it in your registration, and haul more. In WY you can license for 85,500 on all roads. In CO you can haul 85,000 on secondary roads without any permit or license. In MI you can haul 160K with 8 trailer axles and a standard 3 axle tractor.
The reason you'll see the heavy movers with lots of axles and stinger axle combos is to break the weight up for the "bridge weight limit laws".
OR, ID, MT, UT, WY, WA among others have ways to haul more weight with the same rig.