2019 GMC AT4 w. empty trailer bottoming out!

[CDNSS]

I have a 2017 All Terrain and a 22’ enclosed Mission alum car trailer  just added Sumo Springs ( like Timbrens )  they replace factory snubbers. I like better than air bags that I had on last  Silverado  with car in it only 1” sag  gotta be how your hitch set up IMO

Edited April 9, 2019 by CDNSS

[Jack D]

21STCMC - Your pictures do not show your hitch setup, but you seem to have your trailer just sitting on the ball, with the truck springs taking all of the tongue load. That is an improper setup for the weight you are towing. You state that your trailer is 3642 lbs. when empty, and that your race car weighs 2945, for a total of 6587 lbs. This doesn't account for any tools or other equipment that you may also place in the trailer, plus the weight of the hitch, itself. At 6587 lbs., your tongue weight should be kept between 659 lbs. minimum, and 990 lbs. maximum. Your truck is probably rated for 930 lb. max tongue weight, according to your trailering sticker. You need to weigh your loaded rig at a truck scale so that you can position your race car to keep tongue weight within the proper range.

 

CDNSS has posted a picture above that clearly shows that he is using an Equal-i-zer brand weight distributing hitch, one of the best on the market. It is also an anti-sway setup, so it cures both issues. This is a proper towing setup, as it evenly distributes the weight, while eliminating sway causedand porpoising over bumps and seams in the road.

 

I hauled a '69 Camaro in a 24' race trailer, and multiple travel trailers for years, including with a 2002 Suburban half-ton, but always had to use a WD hitch, or I would be facing the same situation that you are. Our state inspection requires a properly rated WD hitch between my half-ton truck & trailer.

 

I had to forego the Z71 option, and go for the Max Towing due to my tongue weights running close to 1000 lbs. I also use an Equal-I-zer brand hitch (10,000 lb total / 1,000 lb. tongue rating). Max Towing package allows for 1130 lb tongue weight.

 

GOOD LUCK!

 

 

[Chevy sad]

Nice post Jack, very informative. 

[Jack D]

On 4/8/2019 at 10:52 PM, 21STCMC said:

Thanks for the spirited discussion, looks like consensus is, there isn’t one.

 

i assure you that my Suburban receptacle is higher than the AT4, I had to remove the drop and install a straight one.

 

On the 2500, I have only owned one and it was a drw and a Royal pain to drive in the city and to park.

 

spoiled on pulling the trailer I have a Seneca that I normally pull it with but wanted something else to replace my Suburban as a daily but still be able to pull the trailer adequately without getting the RV out.

 

Included a couple of half ass pics but you can see it’s on the bump stop and this is with an aluminum trailer without my car loaded.

I hope this helps you out. Saw this while viewing the manual prior to towing for the first time. This is where you should concentrate your efforts. Take your measurements, as shown on page 285, to determine if you need a WD hitch (it looks like you do). Starting on page 279, read ALL towing info regarding trailer weights, loading, hitches, and weight measuring.

 

284 Driving and Operating

Towing Equipment
Hitches
Always use the correct hitch equipment for your vehicle. Crosswinds, large trucks going by, and rough roads can affect the trailer and the hitch. Proper hitch equipment for your vehicle helps maintain control of the vehicle-trailer combination. Many trailers can be towed using a weight-carrying hitch which has a coupler latched to the hitch ball, or a tow eye latched to a pintle hook. Other trailers may require a weight-distributing hitch that uses spring bars to distribute the trailer tongue weight between your vehicle and trailer axles. See “Maximum Trailer Tongue Weight” under Trailer Towing (279) for weight limits with various hitch types.

 

Avoid sharp turns when using a step-bumper hitch to prevent damage. Make wider turns to prevent contact between your trailer
and your bumper.

 

Consider using mechanical sway controls with any trailer. Ask a trailering professional about sway controls or refer to the trailer
manufacturer's recommendations and instructions.

Weight-Distributing Hitch and Adjustment
A weight-distributing hitch may be useful with some trailers. Use the following guidelines to determine if a weight-distributing hitch should be used (shown on page 285).

 

NOTE: Helper springs and air bags will not increase loading capacity ratings. You are still limited to the original factory ratings by law, and you should never exceed any of the listed weights on the door sticker. You may want to check with your state's DMV to confirm.

 

If you are a racer, think of a WD hitch setup as being similar to subframe connectors on a race car, only they flex slightly, instead of being rigid. They make your tow vehicle and trailer act almost as if they were on the same chassis, with weight evenly distributed across all axles. Many brands are out there, but the added benefit of an Equal-i-zer brand hitch, is that it is also a sway control device. The towing experience is fantastic! No sway, despite tractor trailers blowing past you. It is the top-rated WD hitch in the RV industry. I bought mine from AdventureRV.net for around $425. Best I ever used on my car trailer or travel trailers. Closely follow the instruction manual, weigh your loaded truck and trailer as shown in your truck manual, properly distribute the trailer's weight, and you'll find that your truck will tow just fine without changing shocks or springs. Just be sure to stay within all limits.

 

 

[MadCaddie]

 

 

Not that it helps, but wasn't your suburban hitch through the bumper? 

Edited April 10, 2019 by MadCaddie

[Imcrazy]

There is no way on gods green earth that you won't be able to adjust your setup to pull that trailer without being bottomed out... Looks like the trailer is nose down in that pic... Maybe less drop in your hitch would help and like others said get a WD setup... with a properly balanced trailer you should be able to seriously exceed your recommended trailer weight rating without bottoming out your suspension travel...

[Rsktm300xcw]

My AT4 with approx 4000 pound trailer attached. Nearly perfectly level and plenty of room between bump stops.

[Rsktm300xcw]

[Scooter Scott]

This is my AT4 with about 4000 lbs between boat and trailer. I’ll check my bump stops next time I hook it up. I didn’t feel like it was bouncing on the stops when I drove it back home.




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[flowbytwo]

Definitely something wrong with your setup. I have over 6000lbs in my trailer and properly hitched my AT4 sits a little over an inch off the stops. 

 

CAT Scale had this setup at 12360. 

 

That at said I am still tuning things and I plan to add some airbags to stiffen things up when towing as I am up near the RAWR and I could move a little more weight to the other axles with the hitch. No trouble handling this load in the 1000 miles I have over many notable Idaho and Montana passes. The 6.2L and ten speed just works great. 11MPG average with near 14 on the flat when their isn’t wind (it isn’t very flat here ;-) ).

 

If only GM would put this setup in an HD... would probably steal too much money from their over priced diesel. 

[gothp28]

Over 8 thousand lb. 27 ft boat No problem! I was actually surprised on how well it performed.

My old tow vehicle was a Yukon XL so this is an apples to apples comparison of the person complaining. In the future I would use a hitch that is maybe 2" taller but had no problems whatsoever.

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[gothp28]

2 more pictures

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[jamin87ss]

I tow 10k with my 16 all tertain with very little sag, and no issues, i am looking at a at4 and am already concerned that they omly come with 3.23's i have 3 42's, the at4 is tops on my list, has anyone done a similiar move? Hoping this is not a bad move, 

[Imcrazy]

16 minutes ago, jamin87ss said:

I tow 10k with my 16 all tertain with very little sag, and no issues, i am looking at a at4 and am already concerned that they omly come with 3.23's i have 3 42's, the at4 is tops on my list, has anyone done a similiar move? Hoping this is not a bad move, 

The final drive on the 8/10 speed with the 3.23 is about the same as the 6 speed with a 3.42 I believe... 3.42 with the 8 speed is now the 'max tow' setup..

Edited May 9, 2019 by Imcrazy

[Vardo79]

The AT4’s suspension is too soft. Need heavier leaf springs and different shocks. I installed a CST shock set up front and rear along with air bags in the rear. I have zero sag now when towing my 14’ utility trailer with RZR (approx 4,000lbs). Just bought a 25’ tow hauler trailer. Let’s see what it does next...