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Old 11-24-2014, 09:20 AM   #15
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Originally Posted by keymastr View Post
The capacity listed on the hitch is not the capacity of the truck. The same hitch may be fitted to many vehicles that have different capacities. You must look at the vehicle loading information sticker which is located on the drivers door sill for cargo capacity and axle loading. That will vary depending on the options your truck came with.
This feedback kinda saved my bacon. As an inexperienced TT person (like never) I had forgotten about the truck's factory specification for the maximum trailer weight. According to the Ford documentation for a 2004 Ford Crew Cab 5.4L, the max. trailer weight is 8,500 lbs. So I have a hitch capacity higher than I could safely tow. This has changed some of my TT options.
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Old 11-24-2014, 12:11 PM   #16
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So it can tow a boat or other trailer of that size/weight, but not a travel trailer??
I have no idea how to interpret what you are saying. Not a knock on you... I just am not understanding why it would not "apply".

For the most part, the ratings seem to be rather conservative because the manufacturers would have to build in a significant margin of error to protect themselves from safety issues and associated lawsuits. People wrecking their trucks and trailers doesn't exactly sell trucks.
The problem here is all about the truck's "payload" capacity and the "tongue" weight of a travel trailer. Typically, a travel trailer is designed to have approximately 10% to 15% of its total and actual weight to be on the tongue. Not so with a boat trailer or "other trailers".

The tongue weight of a 9000 lb "travel trailer" will have anywhere from 900 to 1350 lbs of tongue weight. Most 1/2 tons have only around 1500 lbs of payload capacity. So depending upon how heavy the trailer "actually" is, your payload capacity will be diminished by that amount and you will only have 600 to 250 lbs left for all that you can have for yourself, passengers, hitch, tools, equipment, camping supplies, etc.

With a 5th wheel, the pin weight will be anywhere from 15% to 20% (maybe more) of the trailer's actual weight.

So you can see that you will run out of payload capacity long before you will even come close to the truck's "advertised" towing capacity.

Hope this makes more sense to you.

Ron


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Old 11-24-2014, 01:04 PM   #17
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I was talking about the "towing capacity rating" that is assigned to trucks by the mfg that is "not applicable".
You're on the right track, but stated poorly. The GVWR and GCWR weight limits are developed by Professional Engineers (PEs) and are certainly applicable. And accurate. If you are claiming the GCWRs and GVWRs are not applicable, then I strongly disagree with you.

On the new trucks, the GCWR is certified by the Society of Automotive Engineers (SAE). So if you want to claim the GCWR is "not applicable", then realize you are out of your league.

But the advertised "tow ratings" and "payload ratings", which are based on the GCWR and GVWR, are not real-world engineered ratings.

The "towing capacity rating" as you call it, is definitely overstated for most people. The manufacturers use the GCWR, but then subtract an unreasonably low truck weight to come up with the tow rating. The truck weight they use is for a base model with no options, and absolutely nothing in the truck but a full tank of gas and a skinny driver. For most of us, subtract about 1,000 pounds from the manufacturers' tow rating to get to a real-world tow rating.

The Payload capacity rating has the same problem. They use the GVWR, then subtract an unreasonably low truck weight to come up with the payload rating. If you expect to use the payload rating to determine max hitch weight you can tow without being overloaded, then you're going to be overloaded when wet and loaded on the road.

The answer for any thinking person is to ignore the tow rating and payload rating and use GCWR and GVWR minus the actual weight of the wet and loaded truck ready for towing. GCWR minus truck weight gives you the actual max weight of any trailer you can tow without exceeding the GCWR. GVWR minus truck weight gives you the actual max hitch weight you can have without exceeding the GVWR of the truck.
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Old 11-24-2014, 07:23 PM   #18
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The answer for any thinking person is to ignore the tow rating and payload rating and use GCWR and GVWR minus the actual weight of the wet and loaded truck ready for towing. GCWR minus truck weight gives you the actual max weight of any trailer you can tow without exceeding the GCWR. GVWR minus truck weight gives you the actual max hitch weight you can have without exceeding the GVWR of the truck.
My 2004 F150 Crewcab 5.4L maximum GCWR is 14,000 lbs. GVWR is 7050 lbs as stated on the door frame. I think you suggested adding a 1000 lbs. to the weight of the truck for 8050 lbs. Then GVMR (14,000) minus 8050 = actual max hitch weight which would be 5950? How badly have I mess up these calculations?
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Old 11-25-2014, 11:01 AM   #19
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My 2004 F150 Crewcab 5.4L maximum GCWR is 14,000 lbs. GVWR is 7050 lbs as stated on the door frame. I think you suggested adding a 1000 lbs. to the weight of the truck for 8050 lbs. Then GVMR (14,000) minus 8050 = actual max hitch weight which would be 5950? How badly have I mess up these calculations?
You completely missed the boat.

Subtract about 1,000 pounds form the tow rating, not add to the truck GVWR.

For example, the tow rating for 2004 F-150 SuperCrew 4x4 with 5.4 engine, 3.55 axle, and 14,000 GCWR is 8,200 pounds. Reduce that to 7,200 pounds to estimate the max weight of a TT you can tow without exceeding the GCWR of the F-150.

7,200 pounds max weight for the TT that has 15% hitch weight is 1,080 max hitch weight.

If the GVWR of that truck is 7,000 pounds, then 1,080 pounds hitch weight leaves 5,920 pounds for the max wet and loaded weight of the truck before you tie onto the trailer.

So the 5,950 you calculated is close to the max weight of the wet and loaded truck before you tie onto the trailer.

Remember that those are estimates. The real numbers can be determined only with the wet and loaded rig on a CAT scale.
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Old 11-25-2014, 09:47 PM   #20
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ATTN: SmokeyWren. I am grateful for your patience and assistance. You have been of great help to me.
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Old 11-25-2014, 10:09 PM   #21
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ATTN: SmokeyWren. I am grateful for your patience and assistance. You have been of great help to me.
+1.
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Old 11-26-2014, 04:43 PM   #22
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Thanks for the flowers, guys. I enjoy trying to help others understand this towing stuff.
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Old 11-29-2014, 01:35 AM   #23
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If I may add, I went through all of this about 12 months ago with Smoky trying to figure out if my TT was safe (I got lucky and it was). while I am not a card carrying member of the weight police, I do suggest that you follow his advice and use a scale to weigh the truck and trailer, alone, separately and for tongue weight. I could not find a certified truck scale here in japan (its weird, I leave it at that) but I was able to use the local scrappers certified scales to check mine and when fully loaded with all gear water genset etc etc etc I only had about 500 lbs left of cargo capacity and was right at max tounge weight for my truck, which surprised me as my TT is small.
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Old 11-29-2014, 09:01 AM   #24
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Go to a hitch dealer and look at a wdh and ask the hitch dealer for answers to your questions.
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Old 12-01-2014, 12:02 PM   #25
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At this point in time only Toyota uses the SAE J2807 testing standard so the tow ratings and braking distances and acceleration times are not indicative of real world performance or problems. I had a Tahoe that was rated to tow 7500 lbs. but it was not safe with anywhere near that load in terms of accelerating onto a freeway and merging with traffic or being able to do emergency maneuvers or be able to stop if there was a problem with the trailer's brakes.
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Old 12-01-2014, 02:08 PM   #26
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At this point in time only Toyota uses the SAE J2807 testing standard so the tow ratings and braking distances and acceleration times are not indicative of real world performance or problems. I had a Tahoe that was rated to tow 7500 lbs. but it was not safe with anywhere near that load in terms of accelerating onto a freeway and merging with traffic or being able to do emergency maneuvers or be able to stop if there was a problem with the trailer's brakes.
Ram stated several months ago that every pickup they make is tested with the rating. Every pickup kept the same tow rating and some even got a higher rating.

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Old 12-02-2014, 05:03 PM   #27
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The GVWR and GCWR weight limits are developed by Professional Engineers (PEs) and are certainly applicable.
As a follow-up question and if you have a minute, do you think that these PE's weight limits have any built-in safety margins? If I add a 20% safety margin, then I will significantly reduce the Maximum Trailer Weight for this truck.

Once again, thank you for your guidance.
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Old 12-02-2014, 08:43 PM   #28
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...do you think that these PE's weight limits have any built-in safety margins?
I was a software engineer, not a chassis engineer, so I haven't attempted to analyze the results of a chassis engineer PE's work. In my field of accounting and management information systems, we didn't have "safety margins". Either the books balance, or they don't. Either the software works without bugs, or it doesn't. So in the world of chassis engineering, when testing at the limit, either the part breaks or bends or it doesn't. If it doesn't break or bend after numerous repetitions of the test, then the vehicle passes the test and the PE keeps his job.


My friends in the automotive world have explained some of the ways they test the end results of their engineering, to be sure it the vehicle performs the way it was designed to performed while hauling and towing the weight it was designed to tow/haul. They've never mentioned safety margins, but I'm sure they have to design in a bit more strength than that required to barely meet the specs. If a spring or shock or wheel breaks, or if the frame warps while testing at the designed limit, then an engineer gets fussed at. PEs are people too - they don't like to get fussed at.
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