Tow Vehicle GARS vs GVWR

The real answer which no one has mentioned IMO is that the vehicle must pass stringent braking standards such as fade, temps, etc. based on a specific number which is the GVWR and it would be cost prohibitive to have all the various GVWRs certified so you will generally find one class of vehicle with a specified GVWR and then for different axle and tire options and even some suspension options you will get various axle wt. ratings whose sum often don't equal the GVWR for that vehicle. A good example is my Van where with the diesel engine there is an option for what is called "ONE UP FAWR" which increases the FAWR 200lbs, but has zero change to the vehicles GVWR.

Larry