We recently received this question about the differences in the Gross Axle Weight Ratings (GAWRs) assigned by axle manufacturers and what’s found on the door pillar sticker on your truck:
Hi, Mike! I have enjoyed several of your articles. I came across the article about payload capacity and how you mentioned that the listed GAWR on your 2013 Dodge Ram was not the actual GAWR that was listed by the axle manufacture. How did you find out the actual GAWR? I am looking at the 2021 Dodge Ram 3500 Limited SRW (I still want luxury). I want to purchase a nuCamp 820. While I realize that the 3500 limited can easily carry it, but I also plan on pulling a 5,500-6,000 pound trailer (I want to start tracking my car at historic tracks around the country). That means, I will lose about 500 pounds of payload just from the tongue weight of the trailer. To safely carry the camper, pull the trailer, carry all the gear I need, and passengers, I need a payload of about 4,300 pounds, but prefer closer to 4,500 to play it safely. I really do not want a dually. The MegaCab with a short-bed will easily work, but I do not want that as daily driver, too. I prefer the SRW 3500. However, if I cannot make it work, I will get the dually. My thought was to get the SRW, and change the wheels and tires, but want to know if this will actually work to get me closer to my payload needs on the 2021 or 2022 model? Any assistance would be greatly appreciated. Thanks, Carlos in Texas.
Hi, Carlos. This is actually a great question. As you know from your previous research, the GAWRs listed by the big three (Ford, GM, and FCA) are thousands of pounds less than the GAWRs listed by axle manufacturers (which in FCA’s case, is American Axle and Manufacturing (AAM)). Why is this? Because of the OEM tires and wheels. For 3/4-ton and one-ton trucks, the big three typically use OEM load range E tires and wheels with a little bit of a safety margin over the truck’s assigned GAWR. For example, the AAM 11.5 rear beam axle that came with our 2013 Ram 3500 SRW has a 10,900-pound GAWR rating, nearly 4,000 pounds more than the GAWR listed by FCA (these ratings can be found on AAM’s website). That’s a big difference. However, that doesn’t necessarily mean you can use that extra 3,900 pounds to haul a bigger camper by getting higher rated wheel and tires. This is because there are other things, besides wheels and tires, that are used to calculate a truck’s GVWR/payload like the strength of the truck’s frame and the OEM components used in the truck’s suspension.
So can you officially raise the payload rating of a Ram 3500/Ford F-350 by getting higher load range F or G wheels and tires? Not officially—only truck manufacturers and a few select spring shops can do that—but you can improve the “safety margin” of your total truck camper load by getting them. Just make sure that what you order is what you get and what they install on your truck. We had this problem happen to us several years ago with nearly disastrous consequences.
What are we currently running on the Truck Camper Adventure Rig? We have Cooper Discoverer AT3-XLT 275/70R18E tires rated for 3,640-pounds each along with Ion rims rated for 4,000 pounds each. For highway driving, we typically inflate these tires to 80 psi rear and 65 psi front. Off-road, we typically run 45 psi rear and 40 psi front.
With regards to the Ram 3500 SRW, if we were shopping for a new truck, we would buy one with the optional “max tow package.” Why? Because this gets you a higher GVWR/payload rating as a result of using AAM’s larger 12-inch rear beam axle. I couldn’t find the GAWR of this new axle (even on AAM’s website), but this beefier axle will have a higher GAWR than the 11.5. My guess is that it would fall in between the 12,000 to 13,000 pound range because of this official statement found on AAM’s website.
Now whether you can get the AAM 12.0 in a single rear wheel configuration (SRW) is the question. The dealerships I spoke to recently say that you can only get this option on a dual rear wheel (DRW) truck, but I know a few 2019 and 2020 SRW owners who were able to order it from the factory as well. But even if you can’t, you can’t go wrong with the tried and true AAM 11.5. It’s been used for years with great success, which is why the FCA is still using it. Indeed, it’s hard to see any truck camper owner topping out the 10,900-pound GAWR of the AAM 11.5 in any truck camper configuration soon.
I just looked this morning on am SRW with max tow package and it doesn’t seem possible from RAM. I have a ’19 2500 4×4 with the 6.4 which all in all I’m happy with but would really like more payload for things like a front bumper/winch arrangement and maybe being able to tow something other than a moped. I’ve looked at 3500’s with similar setup and find that I would gain only about 1000 lbs extra for payload and I’m not sure it would be worth it. Looking for a lighter camper will be a next step as I would like a little extra residual than I can get now. Load capacity on my truck is 3100 lbs.
I seem to recall reading, I think on Dana’s website, that they require zero offset wheels. I’ve been wondering how the super singles get around that, if my recollection is correct.
I have a 2019 Ram 3500 SRW crewcab and the build sheet says, for better or worse, that I have a 12″ rear axle. I also have the HO cummins and the 5th Wheel/Gooseneck towing prep group package. I have assumed that the 12″ came with one of those packages? I already have the truck, so it is not important to me. But, for someone looking, then there should be a way to get the 12″ in a SRW other than just the ‘max tow package’? Or, maybe the towing prep group is another way of saying ‘max tow package’?
I do have a question for you, Mike, or anyone else who might know. What is the differences between a SRW and DRW axle in terms of GAWR? In my case the GAWR goes up by 2750lbs. I know part of that is the tires, or is that only factor? Are springs part of that calculation, or are springs only a factor in GVWR? I do not have access to detailed parts diagrams to see if there is a difference in bearings and or brakes between the two axles.
Have a great day.
Thanks, Dave, for letting everyone know that you were able to get this upgraded axle with a 2019 Ram 3500 SRW truck. This confirms what I was able to learn through my research. I just don’t know if you can get that option on a SRW truck in 2021. Yes, your towing package is essentially the max tow package which is what they are calling it now.
With regards to your question, yes the higher payload rating for dually’s is provided through the extra pair of tires on the rear axle. Some dually’s also have a beefed-up spring pack, usually an overload spring, and larger brakes. It just depends on the make and year of your truck.
You can check part numbers for the bearings, brakes and so on to see if there are any differences. Axle ratings are done as a unit so changes can be one or more items attached to the axle. Bearings are brakes don’t usually change. Factories decide by cost.