When GVW is fixed by the builder, it is based on allowable weight per tire/wheel combo, suspension specifications and axle specifications (including brakes). There is no argument that a duel axle truck will be assigned a higher GVW than the identical truck with one rear axle removed. The problem is that government agencies will not allow anyone (that I am aware of) to assign a new GVW. They are more likely to say that no one is allowed to make these kind of mods after the vehicle is approved, built and sold. I have researched getting a higher GVW for a truck after axle and suspension mods. I have also tried to get GVW down-rated to avoid weight taxes and CDL rules. Both these were in WA state and both times I was shot down. I was told that the WSP would invoke the rules based on the delivered truck data plate, no exceptions, no re-inspections, no new data plates, no engineers GVW evaluations, no...no...no. Chances are that as long as you do not crash your rig (or run into a really knowledgable and energetic truck cop) you won't have any problem running with the standard GVW data plate. Others have asked about getting GVW derated on 5 tons, to avoid weight taxes and CDL rules. Until the states are willing to re-rate, based on axle/suspension changes, I think they are out of luck. Find out what your individual axle ratings are, add them together, then look at your total loaded weight. If that is at or below the max axle weight, go to a scale and weight each axle, be sure you do not exceed that allowable weight. I would not exceed that total allowable axle weight, for three reasons. One, it is a safe weight for your wheels, tires and brakes. Two, if a truck cop does question the allowable GVW of your modified vehicle, you can show them that you are attempting to be legal and safe. Three, in this litigious society, if you should have an accident (even the other dudes fault), you can show a court that you did not exceed the manufactures allowable specs. Hope that this helps someone!