diesel to gas

[buelldude]

I don't do much towing anymore, thinking of going back to gas 3500 dually. I am running into a problem, I can't find any trucks that have a high enough pin rating??? Can any of you that have a 3500 gas dually post pics of your door jam sticker. My pin weight is 3300 on my gooseneck. I think its strange that the payload goes up for the gas trucks but the pin weight goes down. Yes the tow rating goes down as well but the numbers seem to go the other way.

 

So my numbers (diesel/HC)

payload- 5600

pin- 4660

 

The trucks that I can find at the dealer is (gas /HC)

payload- 6100

pin-  2640

 

The numbers are all-over the place, like I said above I want to go back to gas but 

[MORSNO]

That is odd!  Us truck camper guys all know the payload goes up with a gasser, but I've never looked at the pin weight and I'm guessing it is tied to the max towing weight, so it goes down.

[AndrewF]

Seems to be that the pin rating that they assign is just 15% of the total towing capacity, whatever that may be without regard for payload capacity. Not to get into a debate on exceeding factory specs but that one doesn't make a lot of sense, I always thought gooseneck tongue weight could be up to 25% as long as you don't exceed rear axle/spring capacity.

Edited December 10, 2024 by AndrewF

[newdude]

5 hours ago, buelldude said:

I don't do much towing anymore, thinking of going back to gas 3500 dually. I am running into a problem, I can't find any trucks that have a high enough pin rating??? Can any of you that have a 3500 gas dually post pics of your door jam sticker. My pin weight is 3300 on my gooseneck. I think its strange that the payload goes up for the gas trucks but the pin weight goes down. Yes the tow rating goes down as well but the numbers seem to go the other way.

 

So my numbers (diesel/HC)

payload- 5600

pin- 4660

 

The trucks that I can find at the dealer is (gas /HC)

payload- 6100

pin-  2640

 

The numbers are all-over the place, like I said above I want to go back to gas but 

 

 

Pin rating is 15% of the trailer rating on the sticker.

 

So max 5th/goose tow rating on a High Country gas is 17,600lbs, which 2640lbs is 15% of that.  

 

Now.  To make things interesting, the stickers, I can only assume to please the lawyers at GM, are rated at 15%.  GM however in their tow ratings table for these says:  "15 to 25% of the trailer weight is the recommended 5th Wheel or Gooseneck kingpin load."

 

Vehicle Order Guide

[redwngr]

These are from 2023 ratings but they'll be same/similar as other 2020+ 3500's.

Rating labels are struck specific, depending on what trim/options they are born with.

 

 

3500 L5P (SRW and DRW)  have significantly higher gooseneck / 5th wheel tow ratings than the LT8's 

So higher 'pin ratings'.

 

Automatic Transmission Ratings with 5th Wheel or Gooseneck Hitch
Model	Engine	Axle Ratio	Maximum Trailer Weight lbs. (kg)
CC30743 w/SRW	(L8T) 6.6L V8 gasoline	3.73	16700 (7575)
	(L5P) Duramax 6.6L Turbo-Diesel V8	3.42	21500 (9752)
CK30743 w/SRW	(L8T) 6.6L V8 gasoline	3.73	16530 (7498)4
	(L5P) Duramax 6.6L Turbo-Diesel V8	3.42	21300 (9662)5
CC30943 w/SRW	(L8T) 6.6L V8 gasoline	3.73	16700 (7575)
	(L5P) Duramax 6.6L Turbo-Diesel V8	3.42	21330 (9675)
CC30943 w/DRW	(L8T) 6.6L V8 gasoline	3.73	16200 (7348)
	(L5P) Duramax 6.6L Turbo-Diesel V8	3.42	31400 (14243)

 

 

Yes, the LT8's have higher payload ratings. 

Crew Cab

 

 

 

 

Edited December 10, 2024 by redwngr

[lineman1234]

I just checked my door WT camper/plow prep package 3500 srw. 2024 6.6 gasser. 

 

TT 14,500 towing 1,450 pin lbs

5ver/goose, 18,700 towing, 2,805 pin.

4111 payload. 

 

What is interesting, wile comparing my srw to a drw, is the payload and pin go up. Gasser to gasser......

So TT towing drw goes to 16,500, i dont know pin lbs, i dont have one. 

The 5ver/goose, payload on a drw of course goes up, as well as pin...... But,,,, the funny thing, on my comparison, the drw has 300lbs less towing on the 5ver/goose, than my srw. Per charts i have come across. 

 

So its very close at 300lbs pulling a 5ver/goose, but the dually looses out by the said 300lbs pulling vs srw, in my configuration. 

 

Its fun to fluff the feathers on the old rv forums of the you can only tow with a dually and diesel people, when one mentions a gasser dully tows less than a gasser srw. 

[Another JR]

3 hours ago, lineman1234 said:

…

 

What is interesting, wile comparing my srw to a drw, is the payload and pin go up. Gasser to gasser......

So TT towing drw goes to 16,500, i dont know pin lbs, i dont have one. 

The 5ver/goose, payload on a drw of course goes up, as well as pin...... But,,,, the funny thing, on my comparison, the drw has 300lbs less towing on the 5ver/goose, than my srw. Per charts i have come across. 

 

So its very close at 300lbs pulling a 5ver/goose, but the dually looses out by the said 300lbs pulling vs srw, in my configuration. 

 

 

Limited by GCWR maybe?  If they have the same GCWR and the dually weighs 300 lbs more, it would come off the allowed trailer weight. 

Edited December 10, 2024 by Another JR

[bruceb58]

On 12/10/2024 at 2:46 PM, Another JR said:

Limited by GCWR maybe?  If they have the same GCWR and the dually weighs 300 lbs more, it would come off the allowed trailer weight. 

That would be it since the GCWR has nothing to do with suspension and it's total weight dictated by the engine/transmission/differential combo...which is the same between the DRW and SRW.

[buelldude]

I talked to my dealer and they seem to think its just a legal thing going on for GM to cover their behinds. 

 

[Another JR]

On 12/27/2024 at 2:26 PM, buelldude said:

I talked to my dealer and they seem to think its just a legal thing going on for GM to cover their behinds. 

 

I don’t think that dealer is correct.
 

It is driven by the test requirements of SAE J2807, as referenced on the weight sticker. Many different factors can limit the rated payloads, axle ratings, and GVWR and GCWR: suspension capability, braking, engine cooling, transmission cooling, rear axle cooling, acceleration rate, climbing speed, and handling characteristics in braking/turning tests. 
 

For the gas trucks, the GCWR appears to be limited by one or more of the performance tests. I don’t remember all the tests, but they do a climb test where you can be limited by speed, horsepower, engine or transmission cooling, or rear differential temperature. They also do an acceleration test replicating acceleration on a freeway on ramp.
 

So, while the suspension may be able to handle a higher pin weight, the overall vehicle fails to meet the industry standard. Apparently the tests they performed have not evaluated the case where the trailer is well under the maximum total weight but the pin weight fraction is much higher. As I said in the other thread, that is either because J2807 does not have a test for that or because GM chose not to test it. 
 

I’ll try to locate J2807 again to see if I can sort that out.