I am a little late to this discussion but the GVW is around 9% – 10% less the the combined axle weights. This gives you a little wiggle room if you are a little heavy on one axle but light on the other and still at or under your GVW. Most well maintained trucks can haul the combined axle weights without a problem but it may not be completely legal if you are subject to Commercial vehicle Weight enforcement. I found this out when talking to CVE officers after weighing my loaded truck and finding it 200 lbs over the GVW. They told me not to worry as long as I didn’t exceed my combined axle weights. Despite this we had our local spring shop upgrade the trucks springs, shocks and brakes. Hope this helps.