Needing a bit more family room and tow capacity, but still and SUV. As you all know, the list is short. I didn't want a vehicle as old as the Excursion, so that left the 3/4ton Suburban.
We found a super clean, loaded, 2011, with low miles. As many of your know, these things are unicorns. Very rare. Only a small percent of the Suburbans went out as 3/4 tons, and of those an even smaller percentage went out decently optioned. Of those, even rarer are ones that haven't been wrecked or beat down. Happiness.
First part of the build was easy. Bistein B6 or 4600 yellow shocks. Hellwig front sway bar. Absolutely transformed the handling.
Then on went 275/65-18 BFG All-Terrain tires wrapped over some 8.5" wheels with a little less offset. This widened the track just a bit and added just about 1/2" of overall tire height, which is about all the more the truck will take without rubbing. Also wanted to not increase the effective gear ratios.
Now the biggie... The truck is a beast. 14 bolt rear end, stout frame, strong motor. And then they put this wimpy hitch receiver on the thing. It's only rated to 1,000 lbs tongue weight and visual inspection shows the factory hitch to be uninspiring to say the least. This combined with some internet horror stories about poor performance, led me to find a solution.
Obviously, full custom is an option. What I found is that, a quality aftermarket receiver from the previous gen Suburbans (GMT800) are a very close fit. They pickup factory hard points in the frame, but the frame does need to be clearanced in a couple spots. No big deal, the modification are obvious and can be handled with a grinder and sawzall in a few minutes.
So here is when the hassle starts. The aftermarket hitch will sit about 5" below the factory hitch. This means it runs into the factory bumper cover, which will require some trimming or other mods to get the hitch to sit below the bumper.
So this is where I sit. I am exploring my options for getting a more robust aftermarket hitch to fit. I am leaning towards trimming the bumper cover, but there is no emergency and I want to stare at it for a long time before cutting anything. So you all now, the PN for the Curt hitch is 15324.
Any thoughts, ideas, suggestions, experience appreciated.
* This post was edited 04/12/17 01:28pm by PDX.Zs *
Reference Thread 1.
Reference Thread 2
A & A parents of DD 2005, DS1 2007, DS2 2009
2011 Suburban 2500 6.0L 3.73 pulling 2011 Heartland North Trail 28BRS
2017 Subaru Outback 3.6R
2x 2023 Chevrolet Bolt EUV (Gray and Black Twins)
APT wrote:
Great find! We love our Suburban 2500. We just rolled 90k miles last week. I would love a receiver rated to about 1400 pounds. The second thread bellow should really help you.
Reference Thread 1.
Reference Thread 2
Great find! We love our Suburban 2500. We just rolled 90k miles last week. I would love a receiver rated to about 1400 pounds. The second thread bellow should really help you.
Reference Thread 1.
Reference Thread 2
Thank you sir!
I had actually found those threads as I was doing my research. Great info!
My intent. And I see it's working. Is to compile everything related directly to these vehicles (and mods) in an easy to find and use thread.
But...by going to the GMT800 receiver will have you downgrade from the GMT900 receiver
The GMT900 receiver was integrated into the bumper...so it then had to have bumper crash crumple zone duties. They notched the transition bracket to the frame so that it will crumple during a rear end crash
The GMT800 receiver is one of the worst mechanical designs I've seen. Would have fired any of my engineers for designing that thing...heck wouldn't have hired that kind of engineer in the first place...
There were also production quality issues and GM said they fixed it...I'm not going to trust that and here is one failure mode...among many modes of failure. Plus it derives much of it's strength or how it works...is to transfer or depend on those two bolts to the bumper (GM had a cross bar bolted to the bumper inside) in an attempt to turn a torsional loading into a beam loading & torsion (a very bad idea, unless they beefed up both, but am assuming cost reduction...so management wouldn't have approved beefing it up)
![[image]](http://img26.photobucket.com/albums/v77/bentoy/Towing/__hr_SubHitch_008.jpg)
Image from this thread: Need advice from the experts, Posted: 03/06/13 12:56pm
The Curt receiver you are contemplating is what I'd get for my GMT800 K3500 Suburban some day. Mine is okay for now and has served me well over the +21 years since ordered it
The modifications for yours will need to have a 1/4" or so plate made up to transition from the Curt side plates to the 'outside' of the Suburban Frame Rail.
Yes, it will be lower, but that is what good shanks will take care with their multi-hole adjustment
Good luck !!!!
![[image]](http://img.photobucket.com/albums/v77/bentoy/Bens1-1.jpg~original)
-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?...
The factory hitches on both the 800 and 900 series are not awesome. My plan is to use an aftermarket hitch such as the Curt class v unit from a gmt800 on my 900 series truck as it is a close fit.
PDX.Zs wrote:
The truck is a beast. stout frame... but the frame does need to be clearanced in a couple spots. No big deal, the modification are obvious and can be handled with a grinder and sawzall in a few minutes.
I want to stare at it for a long time before cutting anything.
The truck is a beast. stout frame... but the frame does need to be clearanced in a couple spots. No big deal, the modification are obvious and can be handled with a grinder and sawzall in a few minutes.
I want to stare at it for a long time before cutting anything.
Good for you for staring for a while. They always say measure twice, cut once.
While you are staring, I urge you to think very carefully before "clearancing" your frame, especially in the manner shown in the second thread that APT linked to, and that you found in your own research.
From the pics in that thread, it appears to me that the downturned edge of the lower frame flange was trimmed off. But the problem is, that downturned edge is the very feature that strengthens the frame, making up for the significant reduction in material thickness that the frame steel has, when compared to the 2500HD pickup of the same generation, or the 2500 Suburban and pickup of previous generations, especially the GMT400 and earlier, by comparison.
Since on the 2500 Suburban platform, the GMT900 chassis is largely carryover from the previous GMT800 series (unlike the 1500), I am hesitant to say whether or not the material thickness of the rear frame section is thinner on the 900 over the 800, so that's why I say 400 and earlier.
I can tell you, as an owner of the GMT800 Suburban, the frame material is substantially thinner than the previous 400. In otherwords, the frame material on BenK's 3/4 ton Suburban is much thicker than the frame material on my 3/4 ton Suburban, despite both vehicles having the same GVWR, and nearly the same tow rating as equipped. I have measured these thickness differences in several equivalent locations along the length of the frame with a caliper, between a 1999 2500 Suburban and a 2005 2500 Suburban, with both vehicles at my disposal, sitting side by side simultaneously.
If lightening the vehicle for fuel economy, and reducing the production costs of the vehicle to keep the price to consumers in line of sight with inflation, then GM is to be applauded for applying clever engineering to the problem of vehicle towing and hauling capacity, rather than just throwing more metal (material thickness) toward the solution.
An example of one such engineering application in the evolvement of the 2500 Suburban frame from the 400 to the 800 was to introduce up turns and downturns to the open edges of the C channel frame, in targeted areas, so that instead of the frame cross section being in the shape of a C, it is instead the shape of an upper case G, or a lower case zeta in the Greek alphabet, or what is often referred to as a "lipped C" channel.
In places along the frame where ductility is needed, the flanges of the C channel are open and flat. But in places where the frame needs localized strength, or more resistance to deformation, rather than make the entire frame thicker and thus weigh more, GM instead formed a directional change in the flat frame flange formation, adding an up turned or down turned lip in order to increase strength.
And people cut this off?
For the purpose of making their tow rig hitch platform "stronger"?
This doesn't make any sense to me. The key word in "hitch platform" is "platform". And what is the platform for the hitch? Obviously, it is the frame.
It doesn't matter if the hitch added is a Reese Super Titan with twin 3" receiver holes and 25,000 lbs trailer weight capacity... it will still be limited by the platform upon which it is attached. And the capacity of the platform is determined by more than just the capabilities of the drive train. The 14 bolt rear end is meaningless if the already lightened and thin frame flange is yet further weakened by cutting of the lip that was engineered to make up for the thinner material the frame was formed by.
We see the same thing in fully boxed frames. The full box dimension, by virtue of it's shape, provides the resistance to bending that previous open C frames had to rely on material thickness to achieve. That material thickness is then thrifted out, once the frame itself becomes a box. The frame on an equivalent year 1500 Suburban offers a like kind example to compare.
While I don't see any harm in adding a secondary hitch that is rated stronger than the OEM hitch in the 2500 GMT900, perhaps some more staring and thinking is in order before the sawzall and grinder come out.
Meditate twice. Maybe not cut at all.
Try to find a hitch that will fit without shaving off the strengthening lips to the frame, if that is indeed what is required to fit the Curt 15324. Like APT says, 1,400 lbs tongue weight is plenty of capacity for what the rest of the Suburban can handle. Unlike the days of yore, the 2500 Suburban does not share the same frame as the pickups, especially in the rear where the hitch mounts. The 2500HD pickup frames are thicker, have significantly taller frame web height, have slighter wider frame flanges, and have longer directionally changing lips, where formed.
There doesn't seem to be a valid case for compromising the existing engineered frame strength by shaving it, in order to fit a hitch that has 2,500 lbs tongue weight capacity, that in and of itself is still not determinant of the capacity of the hitch platform. Far better to find a hitch that fits without cutting the strengthening lips from the frame flanges.
Have you researched the Reese Titan V aka Towbeast for the GMT800 application? Reese Part number 45013? The upper mounting flange of this hitch's side plates appears narrower across the top, and might be able to nest within whatever downturned flange that people are shaving off the lower part of their GMT900 frame. That might be worth looking into.
We couldnt find another one so now we have an F250 quad cab and Luv it.
PS I did put a K&N on it so it could breath and tuned it with a programmer. Made a big difference.
Happy trails
John, Lisa & Tara">">">
2015 F250 4x4 6.2L 6 spd 3.73s, CC Short Bed, Pullrite Slide 2700, 648 Wts Solar, 4 T-125s, 2000 Watt Xantrax Inverter, Trimetric 2030 Meter, LED Lights, Hawkings Smart Repeater, Wilson Extreme Cellular Repeater, Beer, Ribs, Smoker
BigToe wrote:
Lots of great info
Lots of great info
Thank you much certainly much to consider.
I am still trying to figure out exactly the week point of these hitches.
I have not been able to locate a pic of a failure of the factory hitch. But that would be appreciated.
The failures I have seen on the GM hitched seem to be related to the actual receiver ripping away from the crossmember. If that is the week point, that can be easily fixed by gusseting or plating.
I hear your points on cutting the reinforcing channel. Seems very sensible. I am however stumped as to why the frame in that area has the unused weldnuts in the frame. My assumption was that it was because the GMT900 Suburbans share a frame with the trucks which use those nuts for their hitch.
And so the questions continue.
I did not that there are hitches that, unlike the Curt, seem to be more knife edge in that area and may be able to clear. The DrawTite 41930, which is rated to 1200lb tounge in clearly more robust than stock.
Still need to do some height measurements and understand if being lower with the hitch would help. I tow both a travel trailer and a car hauler.
Thanks all for the input. The best thing I can say is that there does not seem to be a rash of these hitches failing on the 900 series Suburbans, so I am not super concerned. But I will address it.
The holes you see in structures (mainly where weight is an issue), there are large holes in the web. Yup, but designed in AFTER they calculate the increased box section of the whole 'minus' those holes
Any of the upset/bends/ribs/coining/etc to increase the sheet or flat is to increase the box section dimension.
Most after market receivers of traditional design us the OEM frame "C" channel's bottom flange holes. Those holes are designed in and are there BEFORE any hardening/strengthening/etc process(s).
Also note that OEMs now employ much better material science and production science. Meaning that frames today are no longer one piece, but sections that they put together for whichever platform it will end up being
Even though the front and middle sections of the frame are from a pickup, the Suburban's rear section many NOT come from it's pickup cousin
Apologize for the previous short comment on the need for a side plate, or gusset to move (spread) the stresses over onto the Sub's frame.
More detail is that it should tie into the frame web in addition to any OEM flange holes
Farther forward and maybe into the axle arch of the frame
Remember...the OEM receiver is now part of the NHSTA's crumple zone mandate...so I'd guess that rear portion of the frame rail is NOT as stout as before they made it part of the bumper
Leave the OEM receiver alone and it will continue to meet mandated bumper duty...
This is the Curt 15324 you are considering
![[image]](https://assets.curtmfg.com/masterlibrary/15324/images/15324_1024x768_a.jpg)
Love that design and note that the end plate has three components that increase it's box section.
Upper bend is to mate with the bottom of the TV's frame rail's OEM holes, and is the main component to handle side to side moments
Just below it is a triangular gusset at about where the receiver cross tube (a torque tube) is welded to the side plate. Assume there is a higher stress point because of that torque tube's transference force
Bottom has a slight bend. Looks like about 15* or so.
Those along with what looks like 1/4" plate...this guy is STOUT !!!!
Here are some pictures Jbarca took when the GMT900's first came out and shows that crumple zone receiver to frame gusset...and the bottom of the Sub frame rail flange
![[image]](http://i23.photobucket.com/albums/b378/JBarca/Hitch%20Setup/2007rearhitch.jpg)
There appears to be something bolted to the bottom of frame rail just where the Curt receiver would bolt to and that frame flange bendback...all in the way...gotta figure out HOW2 work around them...and do NOT remove that bendback...also shows the notches on the receiver to frame rail bracket (crumple stress raisers)...also, is there room to make a three threaded hole nut-bar for the bolts coming up from the Curt flange?
![[image]](http://i23.photobucket.com/albums/b378/JBarca/Hitch%20Setup/2007rearunderside.jpg)
BenK wrote:
Reslly good info.
Reslly good info.
Thank you much for the info Ben.
So I like that Curt hitch as well. The problem is that is seems to interfere with the added C channel on the Suburban frame. So the channel would need to be relieved. I agree this is suboptimal.
Without access to GMs design, I note that the factory hitch/bumper terminates very early. Meaning it does not reach very far forward on the frame, which as you noted is not desirable. And it seems the C channel under the frame rail is positioned at the terminus of the factory hitch to support it.
My theory is that a longer, real aftermarket hitch wouldn't need these. Who knows?
Anyway, draw.tite makes a hitch that is narrower in the top section that may fit in between the channel and actually reaches further forward than even the Curt unit. But it is only rated to 1200lbs. Even so it is clearly more robust than the stock unit.
Any input greatly appreciated. Aftermarket hitch, reinforce the stock unit.
I would also very much appreciate your best recommendation.
Thanks in advance.
* This post was edited 04/14/17 12:55am by BigToe *
PDX.Zs wrote:
Anyway, draw.tite makes a hitch that is narrower in the top section that may fit in between the channel and actually reaches further forward than even the Curt unit. But it is only rated to 1200lbs. Even so it is clearly more robust than the stock unit.
Anyway, draw.tite makes a hitch that is narrower in the top section that may fit in between the channel and actually reaches further forward than even the Curt unit. But it is only rated to 1200lbs. Even so it is clearly more robust than the stock unit.
PDX Zs, Did you ever get a chance to check out the Reese 45013 hitch? You may find that it too is "narrower in the top section" than the Curt, as well as "reaches further forward" than the Curt, just like the DrawTite 41930... only instead of being limited to 1,200 lbs WD, it is rated to 1,400 lbs tongue weight WD.
Furthermore, being a 2.5" receiver, the Reese 45013 can handle WD ball mounts that are rated up to 1,700 lbs, where the typical 2" WD ball mount is often limited to 1,200 lbs.
In case you hadn't had a chance to look it up yet, I'm going to post a photo of each, so you can see the similarities between the DrawTite Ultra Frame and the Reese Titan (both produced by the same company Cequent), as well as note their differences.
The Reese has an extra hole in the forward most mounting foot, for a total of eight (8) attachment points versus the Drawtite's six (6) attachment points.
And, as earlier mentioned, the Reese receiver is larger in cross section (diameter) of the cross member tube, as well as the receiver itself.
![[image]](https://images-na.ssl-images-amazon.com/images/I/61ZGo-WJ6bL._SL1500_.jpg)
![[image]](https://images10.newegg.com/productimage/A2J8_1_20130816153146102.jpg)
PDX.Zs wrote:
I am however stumped as to why the frame in that area has the unused weldnuts in the frame. My assumption was that it was because the GMT900 Suburbans share a frame with the trucks which use those nuts for their hitch.
And so the questions continue.
BigToe wrote:
Lots of great info
Lots of great info
I am however stumped as to why the frame in that area has the unused weldnuts in the frame. My assumption was that it was because the GMT900 Suburbans share a frame with the trucks which use those nuts for their hitch.
And so the questions continue.
Those questions continue in your head based on your assumption, not based on reality. Let that assumptions go, and at least one of those questions will be relieved.
Absolutely, positively, without any lingering doubt whatsoever, the GMT900 Suburban does not, has not, and indeed cannot "share a frame with the GMT900 pickup trucks" that you are assuming "use those nuts for their hitch." The pickup and SUV 2500 frames are different, in both the rear AND the middle sections. Period. Bonafide fact. Inarguable, indisputable, inescapable reality.
If you came to RV.net for answers and advice, you've found a good place to ask. It's entirely up to you whether or not to believe the answers, but just in case you think I am guessing or speculating on the differences in the frames, know that this is not a guess. It is a certainty. The frames are different.
How is that for clear and unequivocal?
![[emoticon]](http://www.coastresorts.com/sharedcontent/cfb/images/smile.gif "smile")
BigToe wrote:
Absolutely, positively, without any lingering doubt whatsoever, the GMT900 Suburban does not, has not, and indeed cannot "share a frame with the GMT900 pickup trucks" that you are assuming "use those nuts for their hitch." The pickup and SUV 2500 frames are different, in both the rear AND the middle sections. Period. Bonafide fact. Inarguable, indisputable, inescapable reality.
How is that for clear and unequivocal?
Absolutely, positively, without any lingering doubt whatsoever, the GMT900 Suburban does not, has not, and indeed cannot "share a frame with the GMT900 pickup trucks" that you are assuming "use those nuts for their hitch." The pickup and SUV 2500 frames are different, in both the rear AND the middle sections. Period. Bonafide fact. Inarguable, indisputable, inescapable reality.
How is that for clear and unequivocal?
I see... so what you are trying to say in your own understated manner is, "Not the same frame."
I think I get it now. Can't actually argue with someone who has mic'd the stupid thing.
Thanks again for the info and thoughts. I will report back. That 2.5" unit looks very nice, though I was hoping to not have to replace my supply of stingers. Are those adapter sleeves safe? Do we like those here?
The two units above appear to use the same basic sideplatd. At lease shape and thickness. The major difference being the 2.5" vs. 2" square tube. Good find.
Any and all added thoughts appreciated.
* This post was edited 04/14/17 06:23am by PDX.Zs *
But it is easy enough to look at the outsides of the 2500HD pickup versus the 2500 Suburban and see the difference for yourself.
- The frame channel depth can easily be compared without having to get on the ground by simply peering through the open space in the rear wheel wells.
- The shortest possible wheelbase to a GM 2500 pickup is 133.6", which is still 4" longer than the longest (and only) wheelbase of a 2500 Suburban/YukonXL, which is 130"... so the midsection of the frames between the wheels by definition already have to be different in length...
- And the midsections are also different in purpose. The mid section pickup frame is designed to support and stabilize a separated bed and cab that articulates independently, whereas the midsection Suburban frame is designed to support and stabilize a single unitized body. The differences in the frame rails between the two types of bodies can be seen in the upturns and downturns (and lack thereof, and location thereof) in the frame flanges, as well as differences in channel depth and flange width and material thickness.
- Further variability increases with wheelbase and type of cab as well.
- The rear section of the frames aft of axle differ in purpose also, where the pickup only carries a spare tire, but the Suburban holds a fuel tank AND carries the spare tire. This makes a CRITICAL difference in the depth and design of the tubing and/or H-frame CROSSMEMBER(s), as the case may be, between the two types of vehicles. Obviously, without the fuel tank in the way, the pickup can "spare" haha much more room between the rear frame rails above the spare tire for frame strengthening structure commensurate with the hauling capacities of the pickup.
- Rear spring leaf lengths, and spring hanger stamping designs, also differ between the SUV and the pickup 2500. Even where the GVWRs are the same, the anticipated range of variability in actual weights between empty and loaded is much larger in a pickup than in an SUV. In very generalized numbers, the SUV might have an 1,800 lb cargo capacity, whereas the pickup might have a 3,600 lb cargo capacity (equipment depending). Obviously, a full unit bodied SUV with seats for 9 passengers is going to weigh more "empty", than a regular cab long bed will weigh "empty". Hence the rear suspension design in the SUV is optimized for a narrower range of potential loading, whereas the rear suspension in the pickup is optimized for a wider range of potential loading.
The only 2500 semi "pickup" that actually does share the same frame... front, middle, and rear... with the 2500 Suburban is the 2500 Avalanche. It too, is a unibody, despite having an open back. There is a structural reason why the Avalanche is designed to have "rally bars" in the rear that angle backwards from the rear window to the short bed. That angled back bar, covered in plastic, is the critical gusset that unifies bed and cab areas, that takes the place of the fully covered canopy that encloses the rear greenhouse of the Suburban.
Ok, I thought I saw that horse's eyes blink, so I gave it another beating.
On to your question comparing the two Cequent hitches... here again, there is more than meets the eye at first glance between the two.
I'm running out of time with this posting, so I can't pull out the microscope this time around, but do notice
- the additional hole in the rear mounting cleat on the Titan version
- the cast steel entrance collar on the mouth opening of the Titan receiver
- the downturned strengthening bend of the chain loop gusset on the Titan
- the larger holes to accommodate stronger chain loops.
- the receiver tube passes all the way through the cross tube, and is welded on both ends. No upper gusset is needed with that design, that cannot twist out. The top and bottom chords of the cross tube (where the greatest tension and compression occur) are left in tact.
- there actually may be a side plate material thickness difference between the 41930 and the 45013. I would need to verify that first before saying for certain. This was information I knew off the top of my head a decade or more ago, but have since forgotten. I can tell you this... I own both a 45013 and a 45014 (different vehicle application).
The 45014 is made with 5/16" thick side plates... of this I am absolutely certain. I've mic'd the side plate thickness, after being informed by Reese application engineering that increasing plate thickness was their strategy for side plate stability in certain Titan hitches, instead of adding bends to bottom edges of the plate.
Since the 45013 does have stiffening bends formed along the bottom edge of the plate, and since I can't recall what the plate thickness was when I measured that model of Titan, I'm not confident that the Titan is any thicker than the Drawtite Ultra Frame, but there is that possibility. However, I am confident that the Titan has the two extra mounting holes (one on each forward plate mounting cleat), but you can see that in the photos.
I bought the 45013 about a dozen years ago, when the writing became clear on the wall, after Cequent acquired the formerly separate and competing Reese, DrawTite, Hidden Hitch, BullDog, and other long standing brand names of towing equipment manufactures in North America... that American and Canadian production was about to shutter and get shuffled to China.
However, since I've not had a problem with my GM OEM hitch, I've not replaced it. I just kept the 45013 new in the box, stored for the day and time when I think the GM hitch will no longer be adequate for the 2500 Suburban's ratings. For me, that day has never arrived yet, but I see now that the 45013 imported from overseas costs more today at some resellers than the North American made version did a dozen years ago. $408 is a significant chunk of change, although I did find a reseller that claims to sell the same hitch for $225, free shipping.
There is yet another reason why I did not rush to replace the stock GM hitch with the Titan. And the DrawTite and Curt hitches mentioned in this thread are all three guilty of the same sin... that being there load path through the side plates is conferred upon the open floating edges of the lower frame flanges, rather than vertical web supported sides of the lower frame flanges.
The side plates, in all three aftermarket hitches, lining up with the unsupported open end of the C channel frame, regardless of upturned or downturned lips, still applies load leverage across the width of the flange.
If you held your left hand in front of you, forming it into a C shape, with your thumb acting as the lower flange, and your fingers acting as the top flange, and the bulk of your palm acting as the vertical web of the frame... and then took a yoyo string that had a 10 lb plate weight attached, and slipped the yoyo finger loop over the very tip of your thumb, at the fingernail, and left it there... how much strain would that apply to your thumb?
Now, slide that yoyo fingerloop down your thumb, moving it closer to the palm of your hand, as far as it will go. Would not the weight of the 10lb plate dangling at the end of the yoyo string be more bearable, the closer the string is moved to where the root of the thumb is supported?
Such is the same idea with line of load transfer through the side plate of the hitch. For some reason, probably due to cross tube length, as well as the rear spring hanger support stamping underneath the frame, most of the aftermarket hitches for the 2500 Suburban align the side plates with the open, non supported edges of the frame flanges... whereas all three of these hitch brands align the sideplates of their aftermarket hitches fitting other vehicles with the vertical webs of the frames, on the supported edge of the frame flanges.
This is another issue to stare at and think about for a while, as you consider what you are "improving" (or applying excess stress to, beyond the OEM's intent) with any hitch change.
* This post was edited 04/14/17 01:39pm by BigToe *
![[emoticon]](http://www.coastresorts.com/sharedcontent/cfb/images/frown.gif "frown")
Possible options would be to:
Just live with the 1,000 lb WD tongue rating
OEM spec be danged and just go with it over the limit (not my kind of metric, just throwing it out there...but you need to decide if you believe in spec's/ratings/limits/etc). This one will break sooner than later
Modify an aftermarket and this is what I'd do
Still like the Curt a lot, but BigToe is right...these newer designs has every ounce of margin squeezed out...knew that when still working and saw one of our customers using our super computers designing their next gen high end bicycles and at a Ford design center. Management dictates that every penny be squeezed out
So, the Curt type of design is for my Sub's generation frame...where it needs less force distribution and can be kept on a smaller foot print
The Reese is better for your or these latest frames where the rear portion is really not made for towing heavy. Plus, IMHO, think the designers no longer know enough about towing heavy...just CAD jockey's and we coined them "Red/Green Light designers"...design it...run the simulation and fix whatever vectors the super computer says to...then done...
By having a longer end flange, it moves more of the forces forward towards the frame/axle arch
On that, since a 6,000 lb GAWR on the rear suspension...the spring perches should be designed for that specification and then some margin
Getting some or lots of the tongue forces into that area is the smart thing to do...
Key is to NOT weld on the frame and keep welding to a min on the receiver
Transition plate on the rear most flange of the receiver to frame web.
Ditto transition plate on the forward flange to frame and this one might have more room to box in the frame section...without cutting/welding/etc
Good luck...more later...off to buy the Easter Leg of Lamb
BenK wrote:
Can only Internet analyze it so much without benefit of spec's and drawings...
Can only Internet analyze it so much without benefit of spec's and drawings...
Ben... you are famous on rvnet for analyzing... so here is a food for your fodder. Not quite a leg o lamb, but will have to do.
The following photos establish, via specs and drawings, that GM's GMT900 platform 2500 pickup truck frames, in every possible wheelbase, bed, and cab length configuration, are wholly different than GMT900 2500 Suburban/YukonXLs of the same generation.
Since this thread is about hitches for the 2500 Suburban, I've only taken the time to label the Suburban drawings. If the drawing has identifying text in very LARGE LETTERS saying "GMT-900 2007+" on it, then that drawing is for a 2500 Suburban. Otherwise, all other drawings WITHOUT any large letter text added to them are for the GMT900 HD 2500 pickups. There are simply too many configurations of pickups to label them all.
I didn't even post all of the GMT900 truck drawings. I just posted the drawings of the 2500 pickup frames that one might assume would be the same, or near the same, as the 2500 Suburban, so that an anyone who cared to get that deep into the weeds with detail could visually compare the elevation profiles and cross check the measurements to their own satisfaction.
Beginning with 3 Suburban pictures, and continuing with the comparative pickup pictures, we have...
![[image]](http://www.denalitrucks.com/gallery/albums/userpics/11261/normal_GMT900_FUELTANKS.jpg)
![[image]](http://www.denalitrucks.com/gallery/albums/userpics/11261/normal_GMT900_FRAME.jpg)
![[image]](http://www.denalitrucks.com/gallery/albums/userpics/11261/normal_GMT900_HITCH.jpg)
![[image]](http://www.denalitrucks.com/gallery/albums/userpics/11261/normal_CK-207-309-53-43.jpg)
![[image]](http://www.denalitrucks.com/gallery/albums/userpics/11261/normal_CK-209-309-03-53-43.jpg)
![[image]](http://www.denalitrucks.com/gallery/albums/userpics/11261/normal_k-207-307-43.jpg)
![[image]](http://www.denalitrucks.com/gallery/albums/userpics/11261/normal_ck-209-309-03.jpg)
![[image]](http://www.denalitrucks.com/gallery/albums/userpics/11261/normal_ck-209-309-43.jpg)
![[image]](http://www.denalitrucks.com/gallery/albums/userpics/11261/normal_ck-209-309-53.jpg)
![[image]](http://www.denalitrucks.com/gallery/albums/userpics/11261/normal_ck-20743.jpg)
![[image]](http://www.denalitrucks.com/gallery/albums/userpics/11261/normal_ck20753.jpg)
So Ben, hope this turns your
(sad face) into a (happy face)..
Yes, find it VERY enjoyable and challenging noodling possible design/modification improvements...miss the design side after moving into management side...
Can only guess at the force vectors via these docs...though am impressed you came up with these!!!
Going from a WD 1,000 lb tongue max rating to something like 1,200-1,500 lb isn't going to need major redesign...just enough material (thickness, box section, etc) to distribute that 'extra' weight/loading (force vectors) to a wider portion the frame is NOT rocket science...
Suggest you do consult with a ME/PE for peace of mind and documentation for your own liability (never leave that stuff to chance, IMHO)
Unless you have the mind to and the shop, it might cost a few more coins than me with three different types of welders, a plasma cutter (modifying it for 1/2" plate...think upping the air PSI will do that and not blow the handle/gun to pieces), cut-off band saw, 80 gallon 2-stage compressor, and two 55 gallon steel barrels filled with scrap metal for this kind of stuff...
I'll still noodle this, but DO NOT depend on my comments other than just suggestions, as I have zero skin in your game...just an Internet interest in this kind of stuff
HAPPY EASTER !!!!
I went with the Curt 15324 unit. Super easy install. Well, it was a full day, but pretty straightforward. I took the whole back end apart to do it right and clean.
A few observations.
- This hitch is beefy. Full .25" everywhere. Weighs a full 55lbs. A serious piece of kit. Very impressive. The install is doable by one. But I have a full shop and lifts. Better to bring a friend.
- Factory bumper / hitch is very light duty. It weighs about half of what the Curt does. The welds are sloppy, and the metal is thin. It is possible to visually observe torsion in the bumperhitch when load is applied. Ugh!
- Did end up grinding the factory reinforcement plate on one side. The additional metal of Curt bolted in that area more than makes up for any potential loss in that axis. FEA confirmed. :-). You are basically losing 3/8" of support in the y--axis, but adding back in several inches with the hitch. So the frame is supported better than it was prior to mods.
- The factory bumperhitch needed clearancing where the frame extension meets the bumper tube as well to fit the Curt unit. I then cut off the factory tongue so it could be never be used as a hitch again because of this. Then I will just place one of the factory covers.
- The plastic bumper itself comes off easy enough. I cut a nice little clearance notch with a fine blade jigsaw. Looks darn factory if I do say so myself.
- If anyone decides to do this, you will also need a fab a little 1"x3"x.060" spacer to slide under the rearmost mounting holes as the Suburban frame is not flat here, but the hitch is.
- The hitch comes down exactly 4" from stock. This puts it at a much more normal height relative to other tow rigs.
- I replaced all,the hardware with slightly longer brand new metric 10.8 and blue loctite. This was a wobbler as I had a decision as to using the factory hitchbumper mounting plate or not. After inspecting it, I decided it is a very robust unit, the nuts were of high quality, and the full length reinforcing plate is an advantage. It would be possible to use aftermarket hardware here, but you would need to fab a little plate to slide in the frame. No big deal, but the factory hardware was nice in that area.
- My next step is going to be to add some side plates to the hitch to extend it further up the frame. This was described in another thread, and I like the idea.
Additional words are appreciated. I don't claim to have all the answers. My hope was to provide a nice source of info for other owners of these otherwise nice tow rigs.
Stand by for my report on heavy.duty tie rod ends, Rare Parts pitman and idler arms, as well as a very small lift. :-)
Since you were asking about receiver failures, here is what happened on my '01.
![[image]](http://i4.photobucket.com/albums/y134/Burbman/Suburban%20Hitch/306d.jpg)
![[image]](http://i4.photobucket.com/albums/y134/Burbman/Suburban%20Hitch/8d80.jpg)