Safe vs smart vs legal LEO vs legal Civil are five different variations on the same thing.
Safe can be unsafe below ALL the ratings if you are loaded in an unsafe manner. Say too much wt to one side or fore or aft on a trailer, tow rig etc. Or maybe too little HW on the trailer, so it sways.
Smart says, if trailer sways, put more wt or switch wt to front of trailer, so trailer does not sway, along with installing a sway control as an added safety measure.
Legal - leo, is what the LEO that pulls you over has to show is a true black and white in the field legal over weight! This is frankly, for a smaller rig like a 15 series, a max of 500 lbs per inch width of tire. For a typical pickup in todays world that is 5000-5500 lbs per tire on the truck, and around 4000 or so for the trailer tire. Are any of us near these numbers? not likely, so from an LEO standpoint, you are legal from the road bed engineer design max point load limit. OR Federal Bridge Laws! BUT, they can getchya on something else. Like a battery that is too low of voltage to stop you trailer if it runs away and the electric trailer brake is to stop it. Or you can not stop the WHOLE rig in less than 25' from 25mph or some field test they can do. Can the trailer brakes hold or stay locked while you start from a stop? If you fail any of these tests, you are dead in the water. Do you have the correct PAID for license GVW for the truck and trailer. If under, you are good to go, if also under the FBL amount. If OVER any of these two, you are over weight, can get fined, told to move items around so you are under weight, or told to go buy a LARGER paid for gvw for the rig! Been there done ALL the above!
Legal Civil, a lot of gray can occur! You generally speaking, need to stay under any and all manufacture warranty and performance ratings, or you can potentially get sued for negligence. Heck, you can get sued if UNDER these and lose depending upon the how or why or what ever.
Take your pick on what you want to do. I generally speaking follow the axel limits, gvwr for a truck that has axel limits 20-25% above the GVWR......some thing is wrong about this IMHO. BUT, I am NOT the engineer who certifies the rig, per federal standards. These standards are not followed by LEO's that pull you over. ALL they care about is paid for license, are you under from a weight standpoint!
Choose your poison!
Marty
