can't get the gvwr math to work

jcphil wrote:
I guess I still don't get the many people posting in here who advocate for just ignoring vehicle weight ratings. I'm not saying the sky will fall, people will get sued, or anything like that. But it is manufacturer rating. So I guess I just don't get the treat it like "a grain of salt" or "bantha poodoo." I'm not trying to start an argument about it, I'm just confused as to why one would be so quick/willing t
o dismiss a manufacturers rating. I'm doing my best to configure a 1/2 ton truck with a lightweight truck camper. It is a chore. Not saying I'm right or wrong in doing so, but I'm going to stay within the manufacturers ratings. Which sucks because so few 1/2 tons are truly rated for truck camper duties. By way of example: In Ram, only the 2019, 2WD Reg cab 8' bed; in Ford, only trucks w/ the HD payload package; and in GM, no crew cabs.

Maybe there is no risk (legal, warranty, etc), and maybe I'm nerding out to much on the issue. But I can't see just dismissing a Manufacturers rating just because I, a layperson, disagree with it.

The 3/4t and 1t SRW are fitted with a rear axle assembly that has a manufacturer rating of 9000-10,000 lbs. The vehicle builders put springs and wheels on these assemblies that will give the vehicle the best unloaded ride at their intended vehicle classification. If Ford is selling a F250, it does not need 9750 LB springs and wheels attached to the axle with this rating and will use 6000-7000 LB rated components instead to make the truck ride better empty and also save some money on lower rated components. If you are willing to research the components that make up assemblies or sub assemblies of your truck, you will find the lowest rated component degrades the rest to the weakest part. Given a SRW rear unloaded is about 3000 lbs, you have 3000-4000 lbs of available payload using OEM stock configuration. Replacing the weakest links connected to the axle, you have over 6000 lbs.

Going with a 1/2t truck, the semi floating axles are rated for less, but the same process applies of finding individual component ratings to know what real OEM limits are verses paper class limits and which components are the lowest rated and bringing down the assembly ratings.