The following is helpful information, rant, and questions, and roughly in that order...My apologies if this wasn't what you were looking for in the first place... So, CKNSLS recently got me thinking about towing capacities, GVWRs, GCWRs, GAWRs, and other sorts of technical numbers related to the world of towing. For those that don’t know, my Suburban is a ¾ ton for all intensive purposes despite starting its life and still legally being a half-ton truck. But that’s not important for this discussion. What is important is the response I got back from GM when I inquired about my trailer weight rating for the Suburban in stock form… First, a short glossary of what all those acronyms mean to put things into perspective. GVWR- Gross Vehicle Weight Rating. This is the maximum weight of the vehicle as equipped and passengers, cargo, fuel, etc. This rating also includes tongue weight of a trailer. GCWR- Gross Combination Vehicle Weight Rating. This is the maximum weight of the vehicle and any trailer the vehicle is towing. GAWR- Gross Axle Weight Rating. This is the maximum weight that can be put on the respective axle in question. Typically, the rear axle has a significantly higher rating than the front, but not always. These ratings can usually be found on a tag inside the driver’s door jamb of the vehicle along with various other important information. My 1991 Chevy Suburban’s door tag gives a GVWR of 6800 pounds, no GCWR, and a front axle GAWR of 3250 pounds and a rear axle GAWR of 3968 pounds. So, the door tag doesn’t give me any information specific to towing a trailer. My Suburban has a dealer installed GM trailer hitch with a 4000/400 (total/tongue) dead tow capacity and a 9500/1000 weight distributed capacity. However, that’s simply what the hitch is rated for, not the whole vehicle. So, let’s dig deeper into the situation… Friday I placed a call to GM Corporate to inquire about the towing capacity of my truck. After taking down my VIN number, they got off the phone and researched the rating. I got a call back stating that because the truck did not have RPO code Z82 (towing package), that they could only rate the Suburban at 2000 pound towing capacity. Say wha??? After talking with the agent for some time, she kept telling me I needed to inquire either to my local GM dealer or the hitch manufacturer to get the weight rating that the truck could tow. Ok, so let’s get this straight… you want me to go to a dealer whose technicians probably haven’t ever touched a truck that’s over 20 years old and have them tell me how much the truck is rated to tow? Or I should contact the manufacturer of the hitch (YOU, GM) to find out the weight rating? Either way, neither of these people should be able to come up with a real number as to the towing capacity of my truck. So then that got me thinking more. My Suburban is rated to only tow 2000 pounds, yet (for the sake of this argument) U-Haul could sell me a hitch rated for 7500 pounds weight-distributing, and I’m to just assume that’s the towing capacity of my truck? How did they come up with the number 7500? They’re not the manufacturer, and it stands to reason that since I’m buying a hitch from them, that I don’t have RPO code Z82 and according to GM only have a towing capacity of 2000 pounds. How can they in their right minds do that and legally get away with it? I guess they use the standard disclaimer of the end user needing to read the manual to know the weight. Then of course we get into exactly what is changed or included to make up RPO Z82. In 1991, Z82 means it gets the weight distributing hitch I have, it gets pre-wired for a 7-way RV receptacle, and it gets an auxiliary transmission cooler. That’s it. I have all of the above and then some, so technically, while it doesn’t include Z82 from the factory, it’s at the minimum equal to one that had Z82. So what does all this mean? Well, that’s a tough question. Who should I believe and what should I base my numbers off of? GM’s specs off the factory line, the weight rating on the hitch itself, or some other number? Well, let’s pull some more specs into the mix. This time, we’re going to pull from the official GM Restoration Kit packet. Essentially, the Restoration Kit is just the promotional brochure paperwork from the year the vehicle was built, but it has a LOT of gory details about the vehicles down to frame rail thicknesses and the like. On one chart, they list GCWR versus motor, and what gear ratio you need to be at that ratio. With the 3.08 gears the truck had from the factory, the GCWR was only 10,000 pounds. With 4.10 gears and the 5.7L engine, the GCWR is 13,500, but simply saying I have a 7.4L engine changes it to 16,000 which is more than enough for the camper. I don’t understand how getting a marginal amount more engine power can change the GCWR that much, but it does. On another chart, it lists the same info that for a given trailer weight, what class truck you need, engine, and gearset. To haul a 9500 pound trailer, they claim you need a 2500 with the 7.4L engine and 4.10 gears. So, according to that chart, I don’t meet the requirements as a half-ton. I’m confident that with my changes I can haul it though. It’s just not that legal, but was VERY difficult to find. Where does the law come into play when dealing with weight ratings? So, what’s in a rating? A lot, but it can certainly get muddy at times.