squirly towing

[chris989]

Hello All,

I just received my (new to me) 2012 2500 suburban. We have used a 1996 k2500 for a few years now and it is a tow beast. I do not even know out 27' TT (6500#) is back there.

It has supplemental air bags but even without them it handles infinitely better than my 2012.

Not sure if the springs a just softer and causing it to wander. It sure rides nicer than my old truck but the towing blows. The rear end of the truck is a lot higher than my old one, and sags about ~3" when the tongue weight is loaded. I wonder if leveling the truck some might help???

Anyway, Advise on what i can do would be great.

Thanks,
Chris

[Special-Ed]

is weight of trailer centered on the axles of the trailer?

what is the toungue weight of your trailer?

do you have the proper drop/lift of hitch so that the trailer is at proper height?

i used to tow my boat 8200 pounds on a double axle trailer and it had zero issues. i have a 2005 z71 suburban (1500)

no way should you sag 3 inches when putting trailer on... you have something wrong!!!!

[chris989]

I agree the sag it too much.

The back of this 2012 is crazy high in the air. I think it is a softer spring rate compared to the older trucks. With no load my 2012 measure 24.5" to the bottom of the receiver tube and the 96 measures 17.5". both are 8600 GVW 2500 4wd.

& inches higher in the rear and both are bone stock.


Here is a look at it with my new 9" drop shank.
still insanely high to crank up the trailer to hitch up.




same trailer, no changes but my 96.

[chris989]

So i just googles suburban hitch to high and guess what, a thousand post with people complaining about the same thing..

I will go to a larger drop and see if that does not clean things up some. Seams like a lot of unnecessary leverage for a cosmetic bumper??

chris

[chris989]

has anyone tried to air bag a 2500 suburban after 2010? I have searched and no one makes a kit for the newer burbs.

Looking under there it is tight but i do not see why they would abandon the model unless there is just too few out there to support it??

CHris

[chris989]

Ok,

A little update for anyone that may come across this issue.

My 1996 springs are 5/1 rated for 2900 lbs
my 2012 springs are 4/1 rated for 2500 lbs

Just there i lost 800 lbs on the rear capacity.

the trailer tongue weight is ~850. High, but under the max 1k chevy limit.

Long story short, this truck is very capable for pulling and stopping the trailer of 6500lbs but the sway and sag make it unsafe.

The energy stored in the rear springs is too springy for the tongue weight i have? The think just is not safe at highway speeds. ~40mph ok but if i even get to 55 i do not feel in control.

If anyone has some input, chime in. I think unless i can get the bags under the suspension this truck will not be hauling this trailer for any long distances.

[PGSigns]

One of things that may be adding to the issues. The long hitch is adding leverage to the 850# you have at the ball and the hitch may be well over the 1000 it is rated for. A long drop hitch can reduce the capacity of the hitch as much as a 1/3. What weight raring are the rear tires on the 2012. A tire with a softer side wall for comfort does not make a good towing tire. Have you looked at moving weight around in the trailer to improve the balance? Shoot for 10% of the trailer weight. I am going through that now with the toy hauler I have. Not that my duelly cares I just dont like all the tongue weight.
Jimmy

[chris989]

First thing i did was install Michelin LTX 265/70 E load range. I run them on all my trucks.

Looks like I am at ~14% tongue weight.

I am trying to fab some air bag mounts on there today. If i can figure out some mounts i will post a few pics.

If not, i guess we will run the 1996

[chris989]

Originally Posted by PGSigns

One of things that may be adding to the issues. The long hitch is adding leverage to the 850# you have at the ball and the hitch may be well over the 1000 it is rated for. A long drop hitch can reduce the capacity of the hitch as much as a 1/3. What weight raring are the rear tires on the 2012. A tire with a softer side wall for comfort does not make a good towing tire. Have you looked at moving weight around in the trailer to improve the balance? Shoot for 10% of the trailer weight. I am going through that now with the toy hauler I have. Not that my duelly cares I just dont like all the tongue weight.
Jimmy

I just measured from the axle center to the ball and the 2012 is 2" longer.

one inch for the shank and one inch one the truck itself because of the location of the hitch in the bumper.

With my horrible math skills that calculates into another 7% added to the load because of the leverage???

[PGSigns]

What they look at on a hitch is the relationship of the ball to the hitch. The weight it will carry is based on the ball being close behind and even with the hitch. As you put the ball further back and down it changes the way the loads are transfered through the receiver. That is where the loads on the receiver change. If you look at drop hitches you well see as the drop increases so does the load rating. Just lots of factors on what loads and where the loads are seen by the truck than just purely the tongue and trailer weight. The adjustment of the weight distributing hitch and a stiffer set of shocks could make the change that you need.
Jimmy

[chris989]

Well, I got the millermatic out and fabbing at this moment, I aired them up and all looked good, need to disassemble and finish fitting, I hope to have a test drive by tomorrow.

[chris989]

Update for anyone reading this thread.

I bagged the rear of the suburban and it made a 50% improvement. I could tow at 55 easily but i still felt the trailer pushing me around.

My conclusion is the suspension is just to soft for this amount of load. Even if GM rated the truck for 9600 lbs it can not handle the ~900 lbs of tongue weight. I think it is more realistically a class III set up, not a class IV.

I feel if i changed the shock to Monomax or bilsteins it would help a lot.
I could also add the spring or order new 22-907 springs for the rear.
Maybe even stiffen the front to match.

In the end, I am going to continue to use my 96 k2500 burb. It is the last of the "truck" suburbans at 8600GVW.

Anyway, to sum it up, the 2012 wins hands down for power, braking, the built in brake controller and the 6 speed trans but looses overall due to true load capabilities.

Hope i helped someone along the way.
Chris

[68c10airstream]

I think the industry norm for ball height from the ground up is 19.0"- 21.5" So if the truck sits high you need a drop. Think of the frame of the trailer and the frame of your truck should be level and achieve this with a drop/raise hitch assembly, fully loaded and adjust leveling bars accordingly. When my wife and i go camping i'm amazed at how many are not set up properly. Think of a low slung garden tractor trailer with small 10" wheels and notice the neck of the trailer steps up at the coupler area to achieve the 19-21.5 industry spec.