Weight is just one attribute to any TV's ability to manhandle that Mr Murphy situation
Since higher class TV's has 'bigger' stuff...of course the frame is bigger (gauge, box section, etc), suspension is bigger (bigger springs/hangers/shocks/brackets/etc), drive train is bigger (bigger drive shaft, U-Joints, tranny, diff, etc), Tires/wheels (higher class tires and the wheels to accommodate their higher pressures, etc) and a big ETC
Note however, that most OEMs that offer lower class and several higher class TV's will use the exact same basis body/cab/etc in all classes. With some minor changes to differentiate them...some don't even do that...and...that seems to confuse so many into thinking that there isn't much difference between the various class ratings of TVs...
Or just changing one or more of the components to higher class...but...bottom line is that the GVWR, F or R GAWR as still the same...