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Open Roads Forum  >  Towing

 > GM Hitch Deflection Measured - Comments Welcome

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bettered

UpCountry SC

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Joined: 07/26/2004

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Posted: 07/20/05 10:14am Link  |  Print  |  Notify Moderator

BurbMan wrote:

BetterEd, you are correct, the truck is not carrying 100% of the tongue weight with a WD hitch, since the WD bars push some of it back to the TT axles. However, with the WD bars disengaged, no portion of the tongue weight is distributed to the TT axles, and it is all being carried by the truck.

So, my formula will work if you disengage the WD bars prior to weighing.


That's it. My WD bars are always engaged, although not always tensioned. I guess it wasn't clear to me that was your intention in the earlier post, but it makes perfect sense now.

Ed


BetterEd

DW + 2 grandkids + Mini Schnauzer
2005 Chev 3500 Crew D/A 6.6L LLY, 6 x 6 DRW, 3.73
Tru-Flow + Banks, 2005 Flagstaff 831FKSS
Hensley + Prodigy

"Genius may have its limitations...." E. Hubbard 1856 - 1915

bettered

UpCountry SC

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Posted: 07/20/05 12:32pm Link  |  Print  |  Notify Moderator

PSDExcursion wrote:

Quote:

The Hensley I have investigated and heard is is top flight. However in my case my TT is balanced such that I do not have much sway even running without any sway controls. So the Dual cam I have covers the times when things are not perfect and I need some sway control.

Also you have a short 24 ft TT, try towing a 41 ft TT.


Ya know Joe, I already wish I were... I keep admining that Citation...

Regards

Ed

BigToe

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Posted: 08/31/05 11:50pm Link  |  Print  |  Notify Moderator

powlisond wrote:

To all 2000 to present G.M. tow rigs.

I owned a 2002 Chevy Suburban 1/2 ton, was pulling my 1996 Nash travel trailer when the hitch broke, causing me to be slung off the road, killing my 10 year old daughter, breaking my 17 year old sons neck, and injuring the arm on my wife, these hitches I believe are very dangerous. I was using a Reese dual cam sway control hook up, the police heighed my trailer in just under 6000 lbs. I was doing about 55 or 60 mph, when my trailer swayed, I applied my trailer brakes to calm it down, but only made matters worse, and it only took seconds to send me off the hwy. the worst day of my life, P.S. accident happened 6-29-2005. Thank you all for this forum, I'm going to try my hardest to have G.M. recall all of these hitches, it's only time before someone else will be killed, I'll never be able to bring back my daughter, but I might help save someone elses life, so I need all the help I can get. Thanks,Dale



Oh my... words falter...

I have some information that might be useful to you.

PM me if you like.

BurbMan

Islip, Long Island

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Posted: 07/20/05 12:38pm Link  |  Print  |  Notify Moderator

BetterEd, I guess "untensioned" is a better term than "disengaged". Sorry for the confusion. It's amazing how a choice of words can influence meaning and understanding. I guess this is why I find sales and marketing more fascinating than engineering.

Don


2015 Ram 3500 4x4 Laramie Crew Cab Long Box, Cummins diesel

Under renovations:
2002 Lance 811 Slide-In Camper

SOLD: 2001 K2500 Suburban LT 8.1L/4.10
2008 Terry 34' TT many mods, Hensley Hitch


bettered

UpCountry SC

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Posted: 07/20/05 02:28pm Link  |  Print  |  Notify Moderator

Press hard, you're writing through 9 copies....

Ed

powlisond

Hubbard, Or.

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Posted: 08/31/05 11:27pm Link  |  Print  |  Notify Moderator

To all 2000 to present G.M. tow rigs.

I owned a 2002 Chevy Suburban 1/2 ton, was pulling my 1996 Nash travel trailer when the hitch broke, causing me to be slung off the road, killing my 10 year old daughter, breaking my 17 year old sons neck, and injuring the arm on my wife, these hitches I believe are very dangerous. I was using a Reese dual cam sway control hook up, the police heighed my trailer in just under 6000 lbs. I was traveling west bound on Hwy. 50 east of Sacramento doing about 55 or 60 mph, when my trailer swayed, I applied my trailer brakes to calm it down, but only made matters worse, and it only took seconds to send me off the hwy. the worst day of my life, I wish I knew of this forum before my vacation. P.S. accident happened 6-29-2005. Thank you all for this forum, I'm going to try my hardest to have G.M. recall all of these hitches, it's only time before someone else will be killed, I'll never be able to bring back my daughter, but I might help save someone elses life, so I need all the help I can get.

Thanks,

Dale

bettered

UpCountry SC

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Posted: 09/01/05 01:30am Link  |  Print  |  Notify Moderator

I'm so sorry to hear of your loss Dale. My boss just lost a 19 year old daughter to a foolish experiment with "the choking game". I can only imagine the pain you're enduring, and I will keep you in my prayers.

There are some posts on here about problems with the GM hitch. A search may be in order. On my new truck, they've added a little gusset in the "U-Tube" component of the receiver support. The U tube fits between the structural pipe and the receiver box. Obviously, they know there was an inherent weakness in the design. I think it's the pipe.

Good luck to you in your lawsuit. It would be hard to imagine GM getting out of this one, although they can afford high priced defenders and will put you through still more grief before you get any satisfactino. It will be a grind for you, and again, you have my sincere sympathies.

Ed B

BenK

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Posted: 09/01/05 11:37am Link  |  Print  |  Notify Moderator

The cross tube is a "torsion bar", or spring that is twisted during it's usage.

Not stout enough like tradtional, so they went to the bumper bolts to suppliment.

Very poor design and pinching pennies, IMHO.

The addition of the "new" gusset inside the other "U" bracket acknowledges the "need" to increase that area's strength. Still not enough and just a band aid on top of a very poor design.

Thank you for posting, as it's a good thing for others to see that there is a "worst day" out there, as all things engineered is designed not for the good days, but for the worst day out there.

Everyone should file a NHTSA complaint. That is the only thing that the OEM's will listen to. Even then the system is not easy, nor allows everyone to file.

Do a search for "hitch failure" by burbman, that was one of the first threads on this topic and where I learned of this receiver design.


-Ben Picture of my rig
1996 GMC SLT Suburban 3/4 ton K3500/7.4L/4:1/+150Kmiles orig owner...
1980 Chevy Silverado C10/long bed/"BUILT" 5.7L/3:73/1 ton helper springs/+329Kmiles, bought it from dad...
1998 Mazda B2500 (1/2 ton) pickup, 2nd owner...
Praise Dyno Brake equiped and all have "nose bleed" braking!
Previous trucks/offroaders: 40's Jeep restored in mid 60's / 69 DuneBuggy (approx +1K lb: VW pan/200hpCorvair: eng, cam, dual carb'w velocity stacks'n 18" runners, 4spd transaxle) made myself from ground up / 1970 Toyota FJ40 / 1973 K5 Blazer (2dr Tahoe, 1 ton axles front/rear, +255K miles when sold it)...
Sold the boat (looking for another): Trophy with twin 150's...
51 cylinders in household, what's yours?...

BigToe

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Posted: 09/01/05 12:30pm Link  |  Print  |  Notify Moderator

The loss of one's 10 year old girl is pain unfathomable. Please tell us what we can do to help you... private message is invited.

Quote:

"they've added a little gusset in the "U-Tube" component of the receiver support. The U tube fits between the structural pipe and the receiver box. Obviously, they know there was an inherent weakness in the design."


The gusset is a valid observation, but I believe that an incorrect conclusion is being drawn from this observation.

GM did not "add" a gusset on GMT800 platforms where there was none before. GM always had this gusset there on platforms where the hitch is of a higher rating.

The discussions of weak GM hitches on this forum have in large part been initiated by owners of GMT820/830 utilities... in other words Suburbans and Yukons. It was, after all, members like Burbman and JBarca, each owners of Suburbans, who initiated two of this forum's best threads on the subject.

Then, when people with new GMT800 2500HD trucks see the pics of torn hitches in these threads and compare them to their own GM factory hitches mounted to their trucks, they naturally notice a difference... and they find that oft spoke of gusset! From here, they (incorrectly) conclude the GM "knew of the inherent weakness in the original design" and therefore "upgraded" it in the most recent model years. This is an erroneous conclusion, even while there is no doubt that a gusset does exist on the newest 2500HD trucks.

But that gusset was there on the very first 2001 2500HD trucks too. And there is still NO gusset on the very latest 2006 2500 Suburbans.

The fact is, that GM makes at least 3 different versions of this round tube hitch that 1) are specific to the platforms onto which they are installed, and 2) have not changed, nor have they been "upgraded" with gussets, since their design introduction.

Upon closer examination, one will find that there is a lot more different between the gusseted and non-gusseted hitchs than just the gusset itself. The entire frame brackets are of different shape, different length, and different bolt pattern. Overall, the frame brackets to the 2500HD are much longer, and appear more stout, than the relatively short frame brackets found in the Suburban.

And of note, Dale also was driving a Suburban when his hitch failed. And my own measured observations of hitch deflection occured, once again, with a Suburban. The fact that the deflection I observed did not "bounce back" when the load was removed to a level even with what I believe it was prior to the load being applied indicated that my hitch bumper system may have yeilded beyond the material's inherent elasticity. This is concerning, because if this yielding happened, deformation is not far away.

Further evidence of the differences between the hitches, and the fact that these differences existed since the beginning of the platform product cycle, can be found by simply comparing the GM towing guides between 2000 and 2006.

GM rates the receiver hitches in the Suburban as having 600 lb tongue weight, 5,000 lb. trailer weight capacity in the weight carrying mode in model year 2000 when the new body style was introduced, and for every model year since up to the current model year 2006.

Conversely, GM rates the receiver hitches in the 2500HD truck as having 1,000 lb tongue weight, 7,500 lb. trailer weight capacity in the weight carrying mode in model year 2001 when the new body style truck was introduced, and for every model year since up to the current model year 2006. You will find that these are the hitches that have that "gusset."

It is not an upgrade. It is simply a different hitch for a different frame.

Clarifying this point should be helpful to anyone seeking remedy.

* This post was last edited 09/02/05 01:39am by BigToe *   View edit history

BurbMan

Islip, Long Island

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Posted: 09/01/05 01:10pm Link  |  Print  |  Notify Moderator

Dale, I am so sorry to hear of your unbelievable loss. We will keep you in our prayers and hope that you find your way through this tragedy.

I did file an NHTSA complaint, but never heard anything back. I have the form if you need it, just PM me. Also have some pics of the near-catastrophe we had with our hitch.

Big Toe, what you are saying is not consistent with my 2001 Suburban. True, my hitch never had the gusset plate, and not sure if 2500HD trucks had it in 2001 or not. But, my hitch was labeled for 1,500 lb tongue weight (with WD) and max trailer weight of 12,000 lbs. The tow rating of the 2500 Sub with 8.1L and 4.10 rear is 12,000 lbs.

Interesting thing is what looks to be the identical hitch on the 1500 Subs has a much lower rating.

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