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Trailer hitch [message #328165] Fri, 12 January 2018 10:40 Go to next message
Tom Lins is currently offline  Tom Lins   United States
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Registered: February 2004
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The 77 Rear twin we bought in November has this hitch installed on it. Any thoughts on whether this can withstand towing a trailer with a total weight of around 3000 pounds?

It is bolted to the rear cross member of the frame and the bumper.

http://www.gmcmhphotos.com/photos/misc/p64229-img-10631.html




Tom Lins
Elkton, FL
77 GM Rear Twin
Re: Trailer hitch [message #328167 is a reply to message #328165] Fri, 12 January 2018 11:15 Go to previous messageGo to next message
77Royale   United States
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Registered: June 2014
Location: Mid Michigan
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Im not an expert. So take it for what its worth. That hitch does not look like the beefy through the bumper units Mr. Merrell makes which are bolted to the frame in several areas. Yours may be something similar, but Id find out how many different attachment points it has to the frame and not the bumper. With it bolted to the bumper the way it is I would be concerned with tongue weight possibly bending the entire unit downward in a panic stop. With the receiver itself being low to the ground you may need an extended raised hitch which would put some different stresses on things like the bolts holding the receiver to the frame. An engineer would be able to elaborate more on that.

Sure the coach would pull 3000 pounds but how are the brakes on the coach, and does the trailer have brakes in good working order. Those are key components.



77 Royale, Rear Dry Bath. 403, 3.55 Final Drive, Lenzi goodies, Patterson carb and dizzy. Mid Michigan
Re: Trailer hitch [message #328169 is a reply to message #328165] Fri, 12 January 2018 12:24 Go to previous messageGo to next message
Tilerpep is currently offline  Tilerpep   United States
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Location: Raleigh, NC
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I can't really see how it is connected further forward/frame side from the pics...
Towing a jet ski is one thing, towing a 3000 pound car is another.

One of my coaches has a huge collection of steel welded directly to the rear frame, with a ball on a plate extending under the bumper. I asked several folks to look at it at Bean Station with a consensus there was lots of strength. Other coach has the typical through the bumper style that has multiple frame connection points.

Another consideration for using what you have, I would not be able to get my coach in and out of my driveway with your current receiver hitch...add weight to it and it may drag on more occasions.


1975 Glenbrook, 1978 Royale rear bath Raleigh, NC
Re: Trailer hitch [message #328170 is a reply to message #328165] Fri, 12 January 2018 12:56 Go to previous messageGo to next message
lqqkatjon is currently offline  lqqkatjon   United States
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Location: St. Cloud, MN
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I currently have a hitch that is much less in construction.

Towing is rated both by tongue weight, as well as towing weight.

I would have no issue hooking up 3000 pounds of towd car. Tow dolly.

But when it comes to a trailer, i would be looking more carfully as to the actual tongue weight of the trailer. The through bumper ones that our venders produce has a cantilever design that allows higher tongue load for the trailer. You do not want to rely on the rear bumper to carry any weight.


Jon Roche 75 palm beach St. Cloud, MN http://lqqkatjon.blogspot.com/
Re: [GMCnet] Trailer hitch [message #328171 is a reply to message #328169] Fri, 12 January 2018 13:08 Go to previous messageGo to next message
jimk is currently offline  jimk   United States
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It looks like it can handle the PULLING . the Toung weight is an issue, but
if your going to pull a car, it should be good for 6,000 lbs.
We have two hitches, and I have towed the 4.000 lbs mini van over 100.000
miles with our light duty unit and when I slam on the brake the Towed brake
comes on strong and it still tolerates the stress as it is all horizontal.
Pulling a trailer is different as you need to deal with toung weight.
I use the Square receiver HD hitch only because the newer Tow Bars require
the square hitch.
Were an Authorize Blue Ox dealer so we get eddicated on these things .
Never Weld on thing as it is not always reliable. All the tow bar and base
plates are bolted on.

On Fri, Jan 12, 2018 at 10:24 AM, Tyler wrote:

> I can't really see how it is connected further forward/frame side from the
> pics...
> Towing a jet ski is one thing, towing a 3000 pound car is another.
>
> One of my coaches has a huge collection of steel welded directly to the
> rear frame, with a ball on a plate extending under the bumper. I asked
> several
> folks to look at it at Bean Station with a consensus there was lots of
> strength. Other coach has the typical through the bumper style that has
> multiple frame connection points.
>
> Another consideration for using what you have, I would not be able to get
> my coach in and out of my driveway with your current receiver hitch...add
> weight to it and it may drag on more occasions.
> --
> 1975 Glenbrook, 1978 Royale rear bath
> Raleigh, NC
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>



--
Jim Kanomata
Applied/GMC, Newark,CA
jimk-AT-appliedairfilters-DOT-com
http://www.appliedgmc.com
1-800-752-7502
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Jim Kanomata
Applied/GMC
jimk-AT-appliedairfilters-DOT-com
www.appliedgmc.com
1-800-752-7502
Re: Trailer hitch [message #328173 is a reply to message #328165] Fri, 12 January 2018 13:34 Go to previous messageGo to next message
Matt Colie is currently offline  Matt Colie   United States
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Tom,

Executive summary: Go for it guy. But be thinking way ahead. (You should do that with anything anyway.)

Let's get to the mechanics of the situation.
A 3000# trailer should have a tongue weight of 300~400#. Without seeing more of it, I would guess that it will do that safely. I have stood in middle of my front bumper many times while cleaning the windshield, if it had any problem at that load, I would know.
What does worry me is the fasteners into the bottom of the bumper. The fact that the fabricator added those means that he was counting on the bumper for some structure.

My engineering experience tells me that the bumper structure is probably good for the expected loads in a quiescent situation. It would easily be good for a towed or a tow dolly.

Now let's get to the 3k# trailer.
Now you should have active ride height control....
Does the trailer have brakes? How the control is set can make a difference.
How high is the CG?
If it is an empty flat bed, or a small power boat no problem.
If it is a travel trailer or a keel boat (Soling, J-24), would think you are about at the limit because in a hard stop situation, the weight transfer forward could be hard on that hitch. I doubt it would fail at those loads, but there might be permanent displacement.

That is my duly considered opinion. Based on years of building things and towing lots of heavy stuff.

Matt


Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan
OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit
Re: Trailer hitch [message #328180 is a reply to message #328165] Fri, 12 January 2018 17:43 Go to previous messageGo to next message
Tom Lins is currently offline  Tom Lins   United States
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Registered: February 2004
Location: Elkton, FL
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Senior Member
Too answer the questions that have been posed.

What you see in the picture is all there is to the hitch. I stops at the plate you see in the picture.
That plate is bolted to the bottom of the rearmost cross member of the frame.

What started me wondering about this hitch was me wanting one of the aluminum rear bumper toolboxes Frank Jenkins makes.

https://sites.google.com/site/gmcfrank/toolboxes

I guess I will have to either fabricate something like this.

http://www.gmcmhphotos.com/photos/misc/p64231-img-10671.html

Or drop the toolbox idea and go for the HD thru the bumper hitch.




Tom Lins
Elkton, FL
77 GM Rear Twin
Re: [GMCnet] Trailer hitch [message #328184 is a reply to message #328171] Fri, 12 January 2018 19:23 Go to previous messageGo to next message
Tom Lins is currently offline  Tom Lins   United States
Messages: 149
Registered: February 2004
Location: Elkton, FL
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Senior Member
jimk wrote on Fri, 12 January 2018 14:08
It looks like it can handle the PULLING . the Toung weight is an issue, but
if your going to pull a car, it should be good for 6,000 lbs.
We have two hitches, and I have towed the 4.000 lbs mini van over 100.000
miles with our light duty unit and when I slam on the brake the Towed brake
comes on strong and it still tolerates the stress as it is all horizontal.
Pulling a trailer is different as you need to deal with toung weight.
I use the Square receiver HD hitch only because the newer Tow Bars require
the square hitch.
Were an Authorize Blue Ox dealer so we get eddicated on these things .
Never Weld on thing as it is not always reliable. All the tow bar and base
plates are bolted on.


--
Jim Kanomata
Applied/GMC, Newark,CA
jimk-AT-appliedairfilters-DOT-com
http://www.appliedgmc.com
1-800-752-7502
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How far thru the bumper does the Thru the Bumper hitch you are selling extend?
I installed one on my last GMC but I do not remember how far past the bumper it extends.

What I am thinking is since I would have to move the bumper back 2 inches to put the toolbox from Frank
on, as long as the thru the bumper hitch extends more than 2 inches past the bumper it can be made to fit.
It would require cutting the bumper mounting flanges off and repositioning them to where the bumper ended up
but that is not that difficult.

Could someone with one of these measure how far sticks out past the bumper?



Tom Lins
Elkton, FL
77 GM Rear Twin
Re: Trailer hitch [message #328192 is a reply to message #328180] Fri, 12 January 2018 23:10 Go to previous messageGo to next message
Ken Burton is currently offline  Ken Burton   United States
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Registered: January 2004
Location: Hebron, Indiana
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Senior Member

Tom Lins wrote on Fri, 12 January 2018 17:43
Too answer the questions that have been posed.

What you see in the picture is all there is to the hitch. I stops at the plate you see in the picture.
That plate is bolted to the bottom of the rearmost cross member of the frame.

What started me wondering about this hitch was me wanting one of the aluminum rear bumper toolboxes Frank Jenkins makes.

https://sites.google.com/site/gmcfrank/toolboxes

I guess I will have to either fabricate something like this.

http://www.gmcmhphotos.com/photos/misc/p64231-img-10671.html

Or drop the toolbox idea and go for the HD thru the bumper hitch.



I am not sure what the problem is with the tool box and Blaine's through the bumper hitch. If the tool box sits on top of the bumper then probably all you need is a longer receiver. Call Blaine and tell him what you need and he will probably make it for you. I know he as made some special ones in the past for other people.


Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
Re: Trailer hitch [message #328197 is a reply to message #328192] Sat, 13 January 2018 09:04 Go to previous messageGo to next message
Tom Lins is currently offline  Tom Lins   United States
Messages: 149
Registered: February 2004
Location: Elkton, FL
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Senior Member
Ken Burton wrote on Sat, 13 January 2018 00:10
Tom Lins wrote on Fri, 12 January 2018 17:43
Too answer the questions that have been posed.

What you see in the picture is all there is to the hitch. I stops at the plate you see in the picture.
That plate is bolted to the bottom of the rearmost cross member of the frame.

What started me wondering about this hitch was me wanting one of the aluminum rear bumper toolboxes Frank Jenkins makes.

https://sites.google.com/site/gmcfrank/toolboxes

I guess I will have to either fabricate something like this.

http://www.gmcmhphotos.com/photos/misc/p64231-img-10671.html

Or drop the toolbox idea and go for the HD thru the bumper hitch.



I am not sure what the problem is with the tool box and Blaine's through the bumper hitch. If the tool box sits on top of the bumper then probably all you need is a longer receiver. Call Blaine and tell him what you need and he will probably make it for you. I know he as made some special ones in the past for other people.



I did not know that. I will have to give him a call.
Thank You Ken


Tom Lins
Elkton, FL
77 GM Rear Twin
Re: [GMCnet] Trailer hitch [message #328199 is a reply to message #328197] Sat, 13 January 2018 11:46 Go to previous messageGo to next message
jimk is currently offline  jimk   United States
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Registered: July 2006
Location: Belmont, CA
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Senior Member
I goes bck farr enough to attach to the main frame and the bck beam , so it
will take 1,000lbs and bend the main frame as the cross beams on the hitch
ties int it.
The HD hitch was developed by a person origioally in Utah and he quit
producing them so we started copying it as it was the best deign .

On Sat, Jan 13, 2018 at 7:04 AM, Tom Lins wrote:

> Ken Burton wrote on Sat, 13 January 2018 00:10
>> Tom Lins wrote on Fri, 12 January 2018 17:43
>>> Too answer the questions that have been posed.
>>>
>>> What you see in the picture is all there is to the hitch. I stops at
> the plate you see in the picture.
>>> That plate is bolted to the bottom of the rearmost cross member of the
> frame.
>>>
>>> What started me wondering about this hitch was me wanting one of the
> aluminum rear bumper toolboxes Frank Jenkins makes.
>>>
>>> https://sites.google.com/site/gmcfrank/toolboxes
>>>
>>> I guess I will have to either fabricate something like this.
>>>
>>> http://www.gmcmhphotos.com/photos/misc/p64231-img-10671.html
>>>
>>> Or drop the toolbox idea and go for the HD thru the bumper hitch.
>>
>> I am not sure what the problem is with the tool box and Blaine's through
> the bumper hitch. If the tool box sits on top of the bumper then
>> probably all you need is a longer receiver. Call Blaine and tell him
> what you need and he will probably make it for you. I know he as made some
>> special ones in the past for other people.
>
>
>
> I did not know that. I will have to give him a call.
> Thank You Ken
>
> --
> Tom Lins
> Elkton, FL
> 77 GM Rear Twin
>
>
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--
Jim Kanomata
Applied/GMC, Newark,CA
jimk-AT-appliedairfilters-DOT-com
http://www.appliedgmc.com
1-800-752-7502
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Jim Kanomata
Applied/GMC
jimk-AT-appliedairfilters-DOT-com
www.appliedgmc.com
1-800-752-7502
Re: Trailer hitch [message #328204 is a reply to message #328165] Sat, 13 January 2018 15:00 Go to previous messageGo to next message
Johnny Bridges is currently offline  Johnny Bridges   United States
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Matt -

Does 'permanent Displacement' equate out to I bent it?

--johnny


76 26' Eleganza(?) with beaucoup mods and add - ons. Braselton, Ga. "I forgive them all, save those who hurt the dogs. They must answer to me in hell" - ol Andy, paraphrased
Re: Trailer hitch [message #328206 is a reply to message #328204] Sat, 13 January 2018 16:29 Go to previous message
Matt Colie is currently offline  Matt Colie   United States
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Johnny Bridges wrote on Sat, 13 January 2018 16:00
Matt -

Does 'permanent Displacement' equate out to I bent it?

--johnny

Johnny,

It almost does, but "bent" usually means someone cares, and in this case, he might not. It just won't be where it started.
Kind of like the leads on a DIP are "Positively Mis-Aligned".

Matt


Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan
OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit
Re: [GMCnet] Trailer hitch [message #328207 is a reply to message #328204] Sat, 13 January 2018 16:28 Go to previous message
Kingsley Coach is currently offline  Kingsley Coach   United States
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Jim

That is one 'mother' of a hitch isn't it....!!
http://www.appliedgmc.com/prod.itml/icOid/730

Mike in NM


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On Sat, Jan 13, 2018 at 5:00 PM, Johnny Bridges via Gmclist <
gmclist-AT-list-DOT-gmcnet-DOT-org> wrote:

> Matt -
>
> Does 'permanent Displacement' equate out to I bent it?
>
> --johnny
> --
> 76 26' Eleganza(?) with beaucoup mods and add - ons.
> Braselton, Ga.
> "I forgive them all, save those who hurt the dogs. They must answer to me
> in hell" - ol Andy, paraphrased
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>



--
Michael Beaton
1977 Kingsley 26-11
1977 Eleganza II 26-3
Antigonish, NS

Life is too short to hold a grudge; slash some tires and call it even !
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