6.6 gas dually specs needed

[buelldude]

My dealers around here never get a dually (gas) to look at. I have a 6.6 diesel dually that does a great job of pulling my trailer down/up the road. I don't camp as much as I would like, so I'm thinking of going gas. Issue I have is, gooseneck pin is 4660 on my current truck. I have called around to other states due to the lack of trucks here and most say that all the gas trucks have low pin weight ratings. I will not tow over my specs, will it do it---sure. The insurance company says, don't do it because we will not cover you if something happens. Is there anyone using a gas dually out there????? If there is please post some specs

[Another JR]

On an SRW or dually the pin weight rating will be a fixed percentage (15%) of the maximum gooseneck trailer weight rating. Because the maximum trailer weight rating and gross combination weight rating are limited on the dually trucks by drivetrain performance or handling characteristics test results rather than axle weight ratings, the gas truck has a lower pin rating, and there is no difference between the trailering ratings for SRW and DRW. 

Edited December 30, 2024 by Another JR

[Another JR]

I pulled up my trucks weight sticker and the 2024 hd truck brochure.
 

My 2021 3500 cclb SRW gas truck has a sticker payload of 4054 lbs. The maximum gooseneck trailer weight is 16,200 and the gooseneck tongue rating is 15% of that at 2430 lbs. My rear axle rating is 7250 lbs, and my rear axle actual weight empty with driver and full gas is 3340 lbs by scale, so I have 3910 lbs of additional axle capacity. However, the sticker doesn’t let you use all of that axle capacity for tongue weight. 
 

You might think “what’s to stop me from adding cargo in the bed up to the payload or axle rating, and how is that any different from just increasing the pin load the same amount?”  The answer is that you are limited by the gross combination weight rating if you have a max weight trailer, and there’s no margin to allow that additional cargo loading.  The GCWR of my truck is 24,000 lbs. For the 2024 trucks that was increased to 26,000 lbs. NOTE:  The GCWR of a dually is the same as that of an SRW for the reason I mentioned in my previous post. 
 

If you had a lighter weight trailer with a much higher pin weight it probably would have passed the required SAE J2807 tests performance tests (not sure about the handling tests), but they didn’t test it that way and the sticker doesn’t provision for that. You are wise to stay within what the sticker allows. 
 

So, bottom line, for a 2024 3500hd gas cclb DRW, the maximum gooseneck trailer weight rating is 17,800 lbs, and the maximum pin weight will be 15% of that, or 2670 lbs., even though they don’t show it in the brochure table. 

 

Edited December 30, 2024 by Another JR
Added weight limits

[buelldude]

good info, thanks. 

do you have the list for the diesels? I would like to compare it.

 

So for years most if not all have gone with the 20-25% pin rating, now its 15%??? All the manufactures that I have been in touch with still go with20-25% Even GM when I got the truck new. In fact the sent me this link. Look at page 5, SW truck pulling a cimarron horse trailer (18k+ then add in LQ) with tongue weight of 5k plus( I called the people at cimarron for the info). That's way past the specs!!! 

https://www.gmc.com/content/dam/gmc/na/us/english/index/about/trailering-towing/02-pdfs/GMTB20CT300_2020_GMC_Trailering Guide.pdf

This is for my truck to help you get started, read page 40

Tongue or kingpin weight cannot cause the vehicle to exceed the GVWR (Gross Vehicle Weight Rating) or the RGAWR (Rear Gross Axle Weight Rating).

 

My numbers for the trailer are under the above specs. 

trailer- 11040 with a pin of 3500 = 30%   I took out all of my stuff and it went down to 10500 (3150 pin). The trailer is rated for 14k loaded.

Everything I could find stated that the duallys are built with the same parts, not options. So  a high country with all the same rpo codes for both gas/diesel are the same truck till you add a bigger/smaller engine. So the chassis is the same till the engine goes in. If this is the case and it is according to all sources then its about 6-8 hundred lbs different. Going by the above list how is it that 15% is the rule when I can add up to 30% and still fit in the ratings, just not the pin. Wait I still have more payload that can be added, just don't call it pin weight??????? Did I make that somewhat clear what I wanted to say? This topic has made me crazy, year to year the trucks get bigger(hp/tq) and seem to be less on towing. 

 

The pics in the manual is what really made a mess of my homework when looking into my trailer. That trailer had over 2k more in pin weight(the one in the pic, p5) as mine and is being towed by a SW hd. 

 

I want to add, I don't use my truck for a living. I also do not claim to know all that some of you reading do. I just do fact checking. Please add to this post in a positive way, thanks for the reply Another JR

 

 

 

 

Edited December 30, 2024 by buelldude

[Another JR]

I agree with you that it is common in the real world for gooseneck and 5th wheel trailers to have a 20 to 25% pin weight. 
 

I don’t know why GM is using 15% pin weight as their standard. It my be prescriptively required under the SAE J2807 evaluation and rating process, or it may be that’s how GM is able to maximize their trailer weight ratings under the J2807 tests. It’s been a while since I looked at the details of the test requirements and I don’t remember if they dictate 15%. 
 

I looked at the trailering guide you linked. You directed me to page 40. As I view the file, page 40 is data for the Savana van. If you look at the example weight limit stickers they show on page 53, they all appear to use 15% of the maximum trailer weight as the pin weight limit. 
 

All that really means is that, as for every other aspect of loading, there are several limits that apply and you have to stay within the most restrictive of those limits to comply with the sticker. If you have a gooseneck trailer that places 25% of the trailer weight on the pin, you are going to be limited by the pin weight and won’t be able to tow a maximum rated weight trailer. 
 

in your case, if you want to comply with the sticker (as you should) and your trailer has an actual pin weight of 4660 lbs (or were you saying that is your previous truck’s rating?), you will be driven to a diesel 3500 if you are looking at 2024 trucks. They have a max gooseneck trailer weight rating of 31,000 lbs, and presumably a 15% pin rating of 4650 lbs. 

 

Here is the page for the diesel trucks from the 2024 brochure. I also pasted the link so you can go directly there and see it better. 
 

see page 19 of this link:

https://www.gmc.com/content/dam/gmc/na/us/english/index/about/download-brochures/2024-models/new/GMTR23CT200-2024-SIERRA-HD-FO_053024.pdf

Edited December 30, 2024 by Another JR

[newdude]

1 hour ago, Another JR said:

 

I don’t know why GM is using 15% pin weight as their standard. It my be prescriptively required under the SAE J2807 evaluation and rating process, or it may be that’s how GM is able to maximize their trailer weight ratings under the J2807 tests. It’s been a while since I looked at the details of the test requirements and I don’t remember if they dictate 15%. 
 

 

 

 

 

C.Y.A.  Legal wanted them to probably.  If you read the trailering specs in the order guide they call for 15-25% for safe pin weight, but the stickers are all written at the 15% (10% for conventional towing).  

Edited December 30, 2024 by newdude

[lineman1234]

I came across some info comparing my 2024 3500 4x4 regular cab to a same but a dually. 

 

Without getting technical. The dually tows bumper pull 2,000,lbs more but 5ver goose is 300lbs less. So seems for 5ver goose, a srw is more, little but more. More pin lbs on the dually, less pull. 

 

 

[Another JR]

Well, adherence to the J2807 test methods IS how they cover their behinds, so i suspect it is driven by one of those tests if it’s not limited by basic axle capacity limits. So why don’t they allow, at the GCWR and maximum trailer weight, more of the trailer weight to be on the pin?  I think it is probably driven by the handling characteristics in the J2807 circular turning tests or the collision avoidance (sudden lane change) test. Putting significantly greater mass and weight on the rear wheels versus the front causes oversteer due to the greater lateral scrubbing of the rear tires. I don’t think the trailer weight distribution (15 vs 25 % pin weight) would matter in any of the other tests. 

Edited December 30, 2024 by Another JR

[buelldude]

thanks for all the input, and time to reply. I guess stay put with my diesel or get a different trailer. 

[Another JR]

Without an SAE subscription I could not dig deep enough in the referenced test method documents to determine whether SAE J2807 and its referenced test methods prescriptively require testing with 15% pin weight for a maximum weight trailer. However, my daughter’s significant other is an automotive engineer and used to do J2807 and other truck testing for Ram and more recently for an electric semi truck startup. I asked him and he said it’s manufacturers’ choice - 15% is not prescriptively required.
 

He agreed with my guess that GM likely selected 15% pin load because it is within the range recommended by trailer manufacturers and GM, and it allows them to pass the turning and dynamic handling tests with a higher trailer weight than testing at a greater pin weight fraction would allow. 

Edited December 31, 2024 by Another JR

[redwngr]

Probably too late to help, but the 2024 2500/3500 GMC owners manuals says for gooseneck or 5th wheel that pin weight of 15 - 25% of trailer weight 

 

 

2024 3500 DRW Crewcab 4wd 5th wheel/gooseneck ratings 

 

Longbox srw for comparision

Edited February 22, 2025 by redwngr

[MORSNO]

6 hours ago, cemem said:

Gas-powered dual trucks can tow well, but they generally have lower payload and pin weight ratings compared to diesel models due to differences in frame, suspension tuning, and torque delivery. The main limitation is often the rear axle's weight capacity. Your current diesel dually with a 4,660 lb gooseneck pin weight likely has a higher-rated axle, while most gas versions top out lower. If insurance is a concern, it’s best to stay within manufacturer-rated limits. You might want to look at the Ford F-350 or Ram 3500 gas dually specs, as they tend to have the highest ratings in the gas segment.

 

Lots of bad info mixed in this.  Both trucks use the same frame and only the front suspension will be different with heavier rated torsion bars.  Same axles and gas truck will have a higher payload capacity (diesel engine and transmission weight lessen available weight rating).  A diesel will be able to tow much more than a gas.