Denali with trailer sway

[bluebomb78]

I just upgraded tow vehicles to a 2011 Yukon XL Denali. This is quite an improvement from my old 5.3L '99 GMC Sierra. I believe both have the same wheelbase as the truck was an extended cab/short bed. I have enough power to move the boat around but I've noticed just one problem, trailer sway. It seems to occur when I exceed 65 mph and also when I'm around semis on the highway. So now I'm trying to find a way to use my new-found power to maintain decent highway speeds while staying safe. The only difference that I can see between the two setups is the height of the receiver. I'm now 1-1.5" higher than I used to be.

I'm considering three options; weight distribution/anti sway, adjusting the height of my drop hitch, moving the winch post back.

First, weight distribution/anti sway. I've read some threads on here about weight distribution/anti sway setups and the general consensus is that they are unnecessary and that it's difficult to find a setup that will work with the break-away tongue on my Boatmate trailer.

Next, adjusting the height of my drop hitch. My theory here is that since I am 1-1.5" higher than I used to be, can't I just recreate my previous tow experience by setting these heights to be the same. I currently have the heaviest duty 6" drop hitch that Tractor Supply has. I know that there are some on Amazon that have high weight ratings and can go from 4-10" in drop. They appear to be manufactured by Andersen Hitches.

Third, I know another way to modify this is to change where the winch post is, but my thought is that changing the height on my hitch would be a much easier solution.

I've seen Ewok's post on how to weigh the tongue weight and I plan to try that very soon as well. Experiments without data are just speculation, but I was hoping someone else also tows with a Denali and could help shed some light on this.

(My boat is a 2009 22Ve.)

[chpthril]

Fix the obvious, the un-level trailer. Ive towed larger boats with a smaller SUV then an Yukon XL, that thing should handle a 22Ve no sweat.

[JohnnieMo]

There's another easy way to find your tongue weight. Weigh your truck alone, then way with the trailer. Ensure the scale reads each axle independently. You can then calculate tongue weight.

I don't think sway control is needed or even plausible with the trailer. Bit the trailer should be generally level. I just switched hitches and am also trying to get it level again.

Sent from my Z10 using Tapatalk

[Ewok]

Denali with trailer sway

Get one of these, gives you some wiggle room to make sure the trailer is level. I use a 1" drop with my sequoia to get the trailer level. After that, make sure the tires are properly inflated all around, measure the axles to make sure they are square, and make sure the tongue is about 10% of the trailer weight. Make sure your truck is level too, if the front comes up too high you have less steering authority and the entire rig will hunt around on the hwy.

http://www.andersenhitches.com/Catalog/rapid-hitch.aspx

[bluebomb78]

Thanks for the advice. I was pretty surprised that I was having trouble since I was always happy with how the old truck towed. The trailer appears level to my untrained eye but I'll be a bit more scientific about it when I look at it next.

[bluebomb78]

Thought I would follow up for anyone that may read this later. Turns out my leveling eye is not so great. I was about 3-3.5" too low. What I did do was successfully recreate the ball height from my previous tow rig. The wheelbase and other dimensions from the two trucks are all the same so I guess the leaf spring setup on a Z71 must be more forgiving than the air ride setup on the Denali.

I did run Ewok's suggested method (taken from this thread http://www.tigeowners.com/forum/show...d+distributing ) for determining the tongue weight and came up with the following numbers (for reference, the height measurement is taken from the ground to the bottom of the break-away hitch arm):

Height Weight
17.5 120*3 = 360
19.75 137*3 = 411
20.5 150*3 = 450
22 162*3 = 486
23.5 173*3 = 519

Given these numbers, it seems that I may still be light with respect to the 10% rule (assuming the boat weighs 4000 lbs, gas weighs 400 lbs, and trailer weighs 1500 lbs = 5900 * .1 = 590 lbs desired tongue weight), but I'm going to chalk that up to errors in my method or assumptions. I think the key is to get the trailer level as several have suggested and everything is telling me that a 3" drop should do that. Thanks for all the help!

[JohnnieMo]

The auto leveling suspension on that Denali will do its damnedest to keep you level. I've talked to others who have levelled 1800lbs of payload. It is a good system when its all working right.

Regarding the 10% rule, I was told that boat trailers don't really qualify for that. Since the boat is very aerodynamic, and because of the tandem axle, it won't really sway on you. Further, the boat and trailer are perfectly matched. I'd just be careful when you load extra weight in the boat for a long road trip that you do so with some attention to maintaining the balance.

I checked my Z1 and found a tongue weight of 340lbs. That's on a trailer weight of 5900lbs.

How did you end up measuring for level? I also found that eye-ball levelling wasn't very good. But putting a level on the frame also seemed to be unreliable.

[chpthril]

The auto leveling suspension on that Denali will do its damnedest to keep you level. I've talked to others who have levelled 1800lbs of payload. It is a good system when its all working right.

Regarding the 10% rule, I was told that boat trailers don't really qualify for that. Since the boat is very aerodynamic, and because of the tandem axle, it won't really sway on you. Further, the boat and trailer are perfectly matched. I'd just be careful when you load extra weight in the boat for a long road trip that you do so with some attention to maintaining the balance.

I checked my Z1 and found a tongue weight of 340lbs. That's on a trailer weight of 5900lbs.

How did you end up measuring for level? I also found that eye-ball levelling wasn't very good. But putting a level on the frame also seemed to be unreliable.

I parked the trailer in a dead end street in the hood, that was pretty level and unloaded it from the truck. I used a tape to measure to the ground as the end of the trailer and at the same distance forward of the front axle and adjusted the jack until the trailer was level.

Then backed the truck up so the ball was next to receiver. I then calculated what draw bar I need to put the ball 2-3 inches above the height of the level trailer. This compensated for tongue weight. Once the trailer was loaded back on the truck, i was within .5" of the original level position. Not bad for not using an adjustable draw bar.

This worked great for a trailer i towed on a regular basis. But, I still use this same SUV to tow many different boat and trailer combo's, with no sway.

[bluebomb78]

The auto leveling suspension on that Denali will do its damnedest to keep you level. I've talked to others who have levelled 1800lbs of payload. It is a good system when its all working right.

Regarding the 10% rule, I was told that boat trailers don't really qualify for that. Since the boat is very aerodynamic, and because of the tandem axle, it won't really sway on you. Further, the boat and trailer are perfectly matched. I'd just be careful when you load extra weight in the boat for a long road trip that you do so with some attention to maintaining the balance.

I checked my Z1 and found a tongue weight of 340lbs. That's on a trailer weight of 5900lbs.

How did you end up measuring for level? I also found that eye-ball levelling wasn't very good. But putting a level on the frame also seemed to be unreliable.

I did a similar method to chpthril. With the truck unhooked, first I set a level both on the frame and over the wheelwell. That got it somewhat close. The next thing I did was to measure the distance from the concrete pad up to the bottom of the frame at the front and back of the trailer. That was the fine-tuning that got me the last 1/2 to 3/4". It's probably still not perfect but using the top of the ball mount with my 6" drop as my reference and the bottom of the break-away tongue as the new measurement, I was off about 3". By my tongue weight measurements that should take me from around 350 lbs to around 410 lbs. I believe this number includes an added 20-30 lbs due to the measurement equipment (scale, boards, etc.). I should have mentioned that before but I forgot. That leaves me with a tongue weight of 410-30 = 380 with the new 3" drop I plan to use, which is in the ballpark of your tongue weight.