outwestbound wrote:
Sorry to be a pest, but another question to check on methodology; not really interested in a Ford vs RAM truck dust up. I'm looking to buy a 1 ton to tow a 5th wheel. I want to know the math behind a manufacturers published tow ratings between conventional towing (tow behind) vs. a 5th wheel. It's confusing as Ford publishes these two different ratings, but RAM does not appear to. RAM is just one tow rating number and, since I'm not sure about the math and best practices, I don't know how best to interpret RAM's figure.
For example, Ford's 2014 diesel F350, auto transmission 4x4 6.7L DRW 3.73 axle ratio is conventionally rated to tow 18,500 and on a 5th wheel, 22,200. It looks like Ford took 20% of 18,500 and added that back, to get 22,200 (18.5 + 3.7=22.2). I'm guessing this 3,700 pin weight was allocated to the tow vehicle, thereby increasing the 5th wheel tow rating.
Am I correct? If so, how many times is the pin weight counted in the GCWR? (e.g., is the 3,700 pin a deduction from both truck and trailer; a total 7,400 against the GCWR?)
RAM's comparable 2014 3500 AISIN (auto transmission) DRW 3.73 is rated to tow 23,500, based on the chart in the marketing brochure I got at the dealer. RAM just provides this one figure, so how does this single figure compare to Fords' fifth wheel figure? I just want my calculations to be apples to apples, not looking at brands here, with the intent of towing a 5th wheel.
Thanks
So what you are asking is why does Ford limit the conventional trailers to only 18,500 pounds?
I think it has to do with the ability of the hitch system, rather than the possibility that the transmission, brakes, rear axle or other truck systems will be overloaded by towing a conventional trailer that is 19,000 pounds.
Ford does test it's trucks by hitching them to a 18,500 pound trailer, then going on a drive with them. Driving onto the side of the road while going 40 MPH and the right two tires end up in the dirt or gravel. This is dangerous, but if the truck or trailer become unstable, then Ford will not recommend that the truck tow a heavy load while it is unstable. If the truck is stable, then Ford can say "This is safe". Going around curves, up and downhills, if it is safe at 18,500, then Ford will say "You can tow this much".
A fifth wheel is inherently more stable than a travel trailer. So a 35' long fifth wheel being towed by a dually F-350 will be stable at 40 MPH when driven off the side of the road into the gravel, even if that trailer is 22,000 pounds.
Limiting factors on the fifth wheel include the ability of the truck to carry the hitch weight of the fifth wheel. So some manufactures will "Claim" it can tow 18,000 pound fifth wheel with a 2500 series truck. However the pin weight of most 18,000 pound fifth wheels will be about 3,600 pounds. Most 2500 series trucks can not possibly carry 3,600 pounds safely without going way over the GVWR of the truck. Even some SRW 3500 trucks can not carry that much weight and still carry a family with 4 passengers in the cab. Most RV'ers will also take along 100 pounds or more in the pickup bed, such as bikes, firewood, generator, or other camping supplies.
In 2005, Ford changed it's GVWR on the F-250 and F-350 to increase it greatly. While a 2004 F-250 would have a 8,800 GVWR, the F-250 of 2005 and later would be 10,000 pounds. The SRW F-350 has a GVWR from 11,000 to 11,500 or perhaps more (I have not looked them up lately). The DRW F-350 is even higher.
Fred.
