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Old 01-29-2012, 01:05 PM   #1
scrubjaysnest
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Default Hitch receiver ratings

Mr. A in this post, http://www.trailmanorowners.com/foru...7&postcount=23,
prompted this thread.

I think he raises a very valid point and using the search tool didn't bring up anything about hitch receiver ratings.

The bumper on my Dodge is rated for 5000# and a tongue weight of 500#
The factory receiver on the other hand is rated exactly the same without a WDH. With a WDH the ratings go to 12000# and tongue wt of 1200#. Now what made the receiver bolts shear strength get better going to a WDH

This is just one more thing to watch closely when thinking TV and TM towing combinations.

Note to Bill if this doesn't need a separate thread please move to the best place
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Old 01-29-2012, 05:15 PM   #2
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Note to Bill if this doesn't need a separate thread please move to the best place
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To me, this is a valid topic on its own, so I think it should stay right where it is. Thanks, scrubjay.

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Old 01-30-2012, 07:21 AM   #3
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Originally Posted by scrubjaysnest;90281
The bumper on my Dodge is rated for 5000# and a tongue weight of 500#
The factory receiver on the other hand is rated [B
exactly the same[/B] without a WDH. With a WDH the ratings go to 12000# and tongue wt of 1200#. Now what made the receiver bolts shear strength get better going to a WDH
Our F150's factory receiver is similar.

I think these #'s on the factory receiver must be whole truck ratings, not just for the receiver alone (or its bolts). Like you say, it doesn't make sense; and the #s correspond (roughly) to what I read in Ford's towing brochure and the F150 manual's towing section.
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Old 01-30-2012, 10:27 AM   #4
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Scrub,

You said,"The bumper on my Dodge is rated for 5000# and a tongue weight of 500#
The factory receiver on the other hand is rated exactly the same without a WDH. With a WDH the ratings go to 12000# and tongue wt of 1200#. Now what made the receiver bolts shear strength get better going to a WDH?"

I have asked the same question many times, and have never received a satisfying answer. I am aware that the WDH takes weight off the ball/rear axle. But if you already have 1200 pounds at the coupler before placing it on the ball couldn't you still end up with more than 500 lb. on your hitch? (Not to mention that the WDH itself weighs 70-80 lbs.)

When I tried to get someone to explain this to me at RV places, they don't seem to understand the question!

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Old 01-30-2012, 11:35 AM   #5
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Our F150's factory receiver is similar.

I think these #'s on the factory receiver must be whole truck ratings, not just for the receiver alone (or its bolts). Like you say, it doesn't make sense; and the #s correspond (roughly) to what I read in Ford's towing brochure and the F150 manual's towing section.
OK I'll take that back. The WDH #'s on the factory receiver correspond to Ford's literature. The non WDH #'s do not, leaving me just as confused as the rest of you.

Wonder if I removed the tension bars on my WDH? Would that make it a regular hitch? Or if I put the bars on their lowest tension, would there be less tow capacity?
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Old 01-30-2012, 12:38 PM   #6
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Originally posted by ScrubJaysNest:
Quote:
The bumper on my Dodge is rated for 5000# and a tongue weight of 500#. The factory receiver on the other hand is rated exactly the same without a WDH. With a WDH the ratings go to 12000# and tongue wt of 1200#. Now what made the receiver bolts shear strength get better going to a WDH
ScrubJay -

I'm a little confused by part of the question, so please don't beat me up too badly if I've missed something.

What does the bumper rating have to do with anything? Since the factory receiver is not mounted on the bumper, but is bolted to the frame, I would expect it to be independent of the bumper rating. Seems to me that mention of the bumper rating is what we used to call a confusion factor - it is irrelevant to the discussion, but clouds the issue.

I think your question is
"Why does the factory reciever have a rating of 5000 pounds with a weight-bearing hitch, and a rating of 12,000 pounds with a weight-distriuting hitch?" If I am right, I think you asked a good question. Am I in the ball park?

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Old 01-30-2012, 06:43 PM   #7
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Originally posted by ScrubJaysNest:ScrubJay -

I'm a little confused by part of the question, so please don't beat me up too badly if I've missed something.

What does the bumper rating have to do with anything? Since the factory receiver is not mounted on the bumper, but is bolted to the frame, I would expect it to be independent of the bumper rating. Seems to me that mention of the bumper rating is what we used to call a confusion factor - it is irrelevant to the discussion, but clouds the issue.

I think your question is
"Why does the factory reciever have a rating of 5000 pounds with a weight-bearing hitch, and a rating of 12,000 pounds with a weight-distriuting hitch?" If I am right, I think you asked a good question. Am I in the ball park?

Bill
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That is the real question since I use the frame mounted receiver with a older Reese trunion bar style wdh.

The bumper is a secondary question and just adds to my confusion about Dodge ratings because I've never seen a bumper rated that high.

I do know that receiver ratings increase with the use of a WDH whether factory or after market.
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Old 01-31-2012, 06:45 AM   #8
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... Wonder if I removed the tension bars on my WDH? Would that make it a regular hitch? Or if I put the bars on their lowest tension, would there be less tow capacity?
Yes. And yes.

Besides spreading the tongue weight across the axles (allowing TV carrying capacity to not be limited by just the rear axle GAWR), The WDH also spreads the loads better on the hitch receiver attach points.

It does this by placing a positive lift on the hitchball. Essentially, you've got a wheelbarrow where the spring bars are the handles, and you're lifting the tongue weight as you pick them up.

Of course, the real wheelbarrow handles are at the trailer wheels. To see just the WDH effects, set the axle weights to zero in my spreadsheet, and then watch what happens to the spring bar settings and the rear axle load on the TV as you set the the amount of weight that gets moved to the trailer axle from zero on up.

Without a WDH, the weight of the tongue hangs* on the rearmost hitch bolts multiplied by the leverage of the hitch ball vs the bolt pattern. With a WDH, the rear bolts go to zero and the forward-most bolts carry the tongue load (the really good hitch receivers, like I'd expect to find on a pickup with a big tow capacity, have 4 bolts in the pattern up there). So with the WDH, you'd have both lower point loads plus more bolts working and therefore even lower loads per bolt.

*These are static loads. Dynamic loads are potentially much higher and add to/subtract from static loads (don't worry, the guys who build cars and trucks already know about this).
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Old 01-31-2012, 08:39 AM   #9
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The WDH also spreads the loads better on the hitch receiver attach points.

It does this by placing a positive lift on the hitchball. Essentially, you've got a wheelbarrow where the spring bars are the handles, and you're lifting the tongue weight as you pick them up.
...
Without a WDH, the weight of the tongue hangs* on the rearmost hitch bolts multiplied by the leverage of the hitch ball vs the bolt pattern. With a WDH, the rear bolts go to zero and the forward-most bolts carry the tongue load (the really good hitch receivers, like I'd expect to find on a pickup with a big tow capacity, have 4 bolts in the pattern up there). So with the WDH, you'd have both lower point loads plus more bolts working and therefore even lower loads per bolt.
...
I'll have to take a closer look at how my receiver is installed. I don't recall much asymmetry (front to back) in how it's mounted, but if true, this could explain the difference in acceptable tongue loads between a WDH and regular hitch in the factory receiver.

As for the receiver's difference in towing capacity, it must be because the WDH distributes some weight to the TV's front axle. But how much weight, if any, is distributed depends upon the size and adjustment of the spring bars.

Presumably they mean a "correctly" adjusted and sized WDH, whatever that means. Everybody's got a different opinion there ...
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Old 01-31-2012, 10:29 AM   #10
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I'll have to take a closer look at how my receiver is installed. I don't recall much asymmetry (front to back) in how it's mounted, but if true, this could explain the difference in acceptable tongue loads between a WDH and regular hitch in the factory receiver.

As for the receiver's difference in towing capacity, it must be because the WDH distributes some weight to the TV's front axle. But how much weight, if any, is distributed depends upon the size and adjustment of the spring bars.

Presumably they mean a "correctly" adjusted and sized WDH, whatever that means. Everybody's got a different opinion there ...
Weight distribution by a weight distributing hitch is the primary reason for increased towing capacity when you use one. Distribution of stresses on the towing components is a ton-trivial side benefit, but not as important. Check it out in the spreadsheet, which doesn't need to know about hitch receiver geometry: http://www.trailmanorowners.com/foru...ad.php?t=12552

Note: I fixed a calculation in the spreadsheet on 2/1/12. Please download a new copy if you gor yours before that date.
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