I searched for the answer to this but didn’t see anything. Can someone explain how they come up with the different GVWR between the hemi and Cummins long bed srw 3500’s? The GVWR on the hemi long bed is 11400 pounds vs 12300 for the Cummins long bed . I understand the diesel weighs a lot more but I always thought the truck itself was exactly the same besides the motor, same suspension and such. Are the axles actually beefier on the diesel trucks? Just curious, thanks.
Ram Heavy Duty Forum
Register a free account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members through your own private inbox!
How is the GVWR determined 3500s
- Thread starter ansells09
- Start date
H3LZSN1P3R
You're doing it wrong
- Joined
- May 29, 2020
- Messages
- 9,225
- Reaction score
- 8,380
depends what rear axle it has also what options such as rear air assist suspension
The diesel would have heavier front springs due to the engine and transmission weight and the HO has a heavier rear axle. That doesn't necessarily equate to payload however. The hemi probably has a higher payload.
Towing a camper is not going to reduce the GVWR. It will reduce the GCWR (combined weight rating or the maximum tow rating due to wind resistance. However with these heavy duty diesel trucks it probably is not even something to worry about.
Last edited:
H3LZSN1P3R
You're doing it wrong
- Joined
- May 29, 2020
- Messages
- 9,225
- Reaction score
- 8,380
That guy is a bit of a nut so far everything he has posted has been a load of s**t
And you are a pompus ass talking out you butt. I have been doing this for over 50 years probably longer then you have been alive.
As a rep in the rv business that is a long standing figure used when selecting a trailer to fit the tow vehicle
What's that old saying about the pot and the kettle....
kobra
Well-Known Member
- Joined
- Oct 25, 2020
- Messages
- 470
- Reaction score
- 961
Can you share a link to official information from a manufacturer on this?
And, what GVWR are you referencing here? The tow vehicle? Or the trailer?
Thanks,
B
Don't make me break you two up.
H3LZSN1P3R
You're doing it wrong
- Joined
- May 29, 2020
- Messages
- 9,225
- Reaction score
- 8,380
What kinda pot you putting in your kettle? Lol
TBH, Sounds like old wives tales.
I can't begin to tell you how much misinformation/disinformation is passed on to RV buyers from dealers that have been in the business forever and know everything.
But you said GVWR, which is not GCWR. I've never seen a mfr derate their GCWR based on "wind load." The max tow models rated to tow above 25K are only with a gooseneck. A big giant 25K fifth wheel may have a higher wind load, but that's only going to potentially require you to keep your speed down, not reduce the GCWR.
kobra
Well-Known Member
- Joined
- Oct 25, 2020
- Messages
- 470
- Reaction score
- 961
Well then what you're saying is confusing and misleading. The weight you can tow is not GVWR; it's tow ratings. And for years, pickup manufacturers have used the SAE J2807 towing standards, and that standard says nothing about reducing GVWR or tow ratings depending on whether it is a flat trailer or a box trailer.
What the SAE and manufacturers DO describe is the differences in tow ratings depending on the hitch type; with ball hitches having reduced ratings compared to 5th wheel hitches, compared to gooseneck hitches.
To me, if you are going to make definitive statements to challenge someone here, like "all manufacturers determine", you should have no problem providing a link to at least 1 manufacturers recommendations. Especially when you make claims about your years of experience, I find it strange that you would aren't able to provide any references at all. Retired has nothing to do with that.
I had years of heavy trucking experience towing both vans and flat decks, mostly with heavy equipment (over 100,000lb loads sometimes with boosters and jeeps and over 40 tires). With respect, I don't think you've towed with flat decks; wind resistance is far higher on many flat deck loads than with a box trailer. I've long since retired from the trucking industry, but if anyone asked me to provide up to date information about that industry, I could find at least some references within minutes.
But just in case I was missing something, I spent some time looking at the tow ratings from the big 3 pickup manufacturers. There is nothing in any of their tow guides to confirm what you are saying. And, just for giggles, I looked up their tow ratings from over a decade ago; still nothing like what you are saying between flat or box trailers. Didn't take long...
So, now I'm going to challenge the other statement you made:
"The way the state tow capacity is misleading because of the way they determine the load ratings"
Can you provide references, or any other information, to backup why you made this statement?
B
kobra
Well-Known Member
- Joined
- Oct 25, 2020
- Messages
- 470
- Reaction score
- 961
@ansells09 - So in all the wrangling, I'm not sure you got the answer you were looking for...
I don't know the formula for how RAM exactly determines their GVWR, but in generic terms here are some of the considerations:
-engine and engine braking, along with brakes. (higher GVWR considers the ratings for acceleration and deceleration so that's why all 3 make a difference)
-strength of frame and length of frame (cummins frames and engine mounts obviously need to be much heavier than gas engines. Also longer frame resists twisting more)
-suspension and axle ratings, as you've mentioned.
What is even more interesting to me, and I didn't realize it when I ordered my truck, is the difference between the Cummins HO, Short box 4x4 cab models -the mega cab has a higher GVWR than the Crew Cab. (12,300 for mega and 11,800 for CC)
I assume on the above example the only difference is length of frame, and that is where additional GVWR was allowed. Which is again interesting, because the length of the frame on the mega cab is in between the length of the CC shortbox and longbox, yet it gets the higher rating the same as the longbox.
Hope that provides a better answer...
B
Actually the Ram 3500 Max tow package is rated to tow 30K fifth wheel and 37,100 gooseneck. Ram even supplies the fifth wheel hitch rated at 30K.
kobra
Well-Known Member
- Joined
- Oct 25, 2020
- Messages
- 470
- Reaction score
- 961
Yes, and that agrees with my prior statements about manufacturers tow ratings and how they specify them based on hitch type, not flat vs box trailer. And, nothing about the stated RAM specs that are a 10% standard difference that apparently all manufacturers use.
You can get box trailer gooseneck trailers also - just ask the horse guys.
Or, did you have a different point you were making?
B
No. Somehow this thread went sideways from what the OP wanted to know how GVWR was determined for a particular truck to trailer tow ratings being determined by GVWR and wind resistance. The only time I have seen wind resistance (frontal area) being a manufacturer's concern was for underpowered family sedans and NOT for these trucks. So in other words, I agree with you. Not sure what "housedrx" was talking about as I was totally confused by his statement. Beside, it is all in the manual. LOL