Thanks for posts to my confusing question. I was trying to understand if there was a "best practice" way by those in the RV community of converting manufacturer's towing ratings to a common standard of comparison. Clearly, there is not, because current regulatory structure leaves manufacturer's to their own methodologies and procedures to arrive at their product's capabilities, leaving consumers with no objective means of comparison.
Based on numerous
articles, manufactures agreed to comply with Society of Automotive Engineers (SAE) standard J2807: Performance Requirements for Determining Tow-Vehicle Gross Combination Weight Rating and Trailer Weight Rating for 2015 1/2 ton trucks. But, no agreed date has been scheduled for bigger trucks.
J2807 was available in 2013 and articles say manufacturers have been making mechanical (not just smoke and mirror changes to computational methodology) to 3/4 and 1 ton trucks, so big reductions in their figures may be minimized, once they all agree to adopt the standard. One article
here, claims that the rating inflation is much greater in the 3/4-1 ton trucks; like 3,000 - 4,000#, based on 2013 figures. Hopefully if manufacturers have worked on improving mechanical capacity since 2013 as a way to minimize their embarrassment when they all agree to comply and "come clean", that the 2014 published figures aren't so inflated as they were in years past.
I want a certain % safety cushion under the truck's "capacity", so I'm taking 10% off RAM's published towing rating, just because I don't trust RAM (or any other). Then, I'm taking a second 10% (total about 20%) for my own peace. So, with the RAM 3500 I'm looking at, I'll lower my rear end gear from 3.73 (23,500) to 4.10 (29,000) to make my cushion, knowing that 23,500 is now a more reliable figure. I'll burn more fuel and run higher RPMs, just to be safer, because manufactures can't be trusted; very frustrating.
