G.R. White thinks tow ratings are overrated. This is despite efforts like the Society of Automotive Engineers (SAE) J2807 tow-rating standard.
Alongside power, economy and payload, trailering ratings are the Holy Grail of light truck marketing. However, despite recently adopted Society of Automotive Engineers (SAE) standards that put everyone on the same footing, the value of tow ratings is almost irrelevant in the real world.
There’s only one way to know what your pickup can tow, and it involves a trip to the scales, knowledge of what Gross Combined Weight Rating (GCWR), GVWR and Gross Axle Weight Rating (GAWR) are and how to calculate it all. Sure, the salesman is correct when they say your truck could pull this or that, but will they be in court or the service drive with you if something goes wrong?
The problem is that measures like in the J2807 standard have carefully specified conditions and assumptions and the actual usage may or may not reflect those conditions and assumptions. White also runs afoul of the measurement problem in his suggested solution as well. J2807 is an attempt at a s usability measure determined by actual performance evaluation. Weight ratings are engineering specifications that are estimated from design and materials considerations. A key item that should raise a red flag is when White refers to the legal system as the only time that argument has any merit is in cases of gross negligence.
Of course, you do not want to abuse the engineering specifications for your rig but you do need to be aware of their source. GAWR and wheel and tire ratings, for example, are close to individual component specific and that means they need careful attention. GVWR is more vague as it is about the vehicle as a system of parts. GCWR is even less precise as it depends upon assumptions about frontal wind area and other factors that depend upon specific circumstances. It also pays to keep in mind that, as engineering specifications, these ratings have a safety margin built in and there are also usually conditions and assumptions considered that can be manipulated for special circumstances. Speed and temperature are two of those conditions and assumptions that can be manipulated to adjust ratings, for instance. Sometimes, like for tires, these conditions are actually specified.
If you remember a family RV experience as a kid back in the 50’s or 60’s, you will recall a family sedan or station wagon with a 100-200 hp engine and a three speed transmission towing a trailer weighing maybe a ton or so. Downshifting on nearly any grade was to be expected and their wasn’t much in the way of creature comforts such as air conditioning or even bucket seats. These days, the tow vehicle is an SUV or pickup truck with nearly double the power of that old sedan and a transmission with double the gears, too. The trailer likely ways four tons or more. People seem to get irritated if their automatic transmission downshifts out of overdrive going up freeway grades and turning off the AC as suggested on I15 going East of Baker is not a consideration.
Yes, it’s prudent to make sure your rig is competent and capable before you buy but people also learn from experience. You find a tow vehicle and a trailer that fits your needs and is comfortable for your RV experience. The choice isn’t a permanent one as your needs, interests, and preferences will change over time. Equipment also keeps getting better, too.
Take care. Drive safe.