From state to state alot permit rules a regs differ. They will give you a gross limit, also depends on how many axles you are running, but you still will have axle group limits as well. Like Illinois you could be set for 92,000 on 5 axles, so your gross is 92,000, but your axle group would be something like 12 steer, 40 drives and 40 trailer. But if you were permitted at 96,000 on 5, i think its still 12 steer and 42 and 42.
Yes if your doing 80,000 in say ohio, but florida allows 40,000 on a tandem Now if your permitting to haul over weight, then theyd go by their state chart for what they will limit a tandem group at. You cant get and over weight permit for 92,000 and just put whatever weight ya want on whatever group ya want as long as your not over 92,000.
34k is Legal axle weights. Non divisible overweight loads have very different criteria. Most every state allows 40k minimum for a tandem, some are up to almost 47k. Then there is Road Bans during spring thaw times and things change again...welcome to the constantly moving target of fun zone!
Makes it tough to travel between states sometimes. Some states just worry about gross, some want axles groups to be right, and some will even scale each axle.