WDH and Anti-sway

I need the advice of more experienced people like those on this board.

We have a 2004 GMC Envoy and a 19ft Aerolite two axle trailer. The trailer weighs about 4400 lbs loaded and rides level with my regular hitch. It pulls good around town but I haven't had it out on the road. The Envoy has air ride suspension on the rear and I have heard that this type suspension  and WD hitches don't play well together. I always worry about swaying because of the many accidents caused that way. Do the benefits of the hitch outweigh the problems of the suspension, or is the problem of the hitch and the  suspension not playing well together over blown.

I depend on the knowledge of this board especially since this is completely out of my zone of experience. Thanks in advance for your recommendations.

I am NOT an expert here!  My gut feel is that the WD hitch is designed to raise the fear of the TV by pushing some weight forward, or distributing the weight differently.  Your air suspension is doing this.
 
For sway control, the most important thing is making SURE you have at least 10% - 12% of the total TT weight carried by the tongue.

Check this video.

https://imgur.com/gallery/3PQFK7Y

Watch and read the videos and articles on the Equalizer site they explain it very well.

https://www.equalizerhitch.com  They are the original inverters of this kind of system.

Sway is caused by not having enough weight at the front of the trailer.  Trying to keep the trailer tongue weight light so the combo doesn't sag in the middle transfers too much weight rearward on the trailer, creating sway conditions.

You should have at least 10-15% of the trailer's weight on the tongue (440-660 lbs).  Less than this can create sway.

The only caveat is whether or not this much hitch weight is removing enough weight from the front end of the truck to be hazardous.

Think of the truck frame as a teeter-totter with the fulcrum point being at the rear axle.  As you add weight to the hitch, it counter-balances some weight at the front end.

An equalizing hitch restores this weight by creating a bridge across the hitch, raising it up by creating leverage pressing downwards towards the trailer axles and forward towards the front axle of the truck.  As the springs compress, they transfer more weight to the road.

The Envoy's air suspension does nothing for weight distribution, all it does is raise the fulcrum point at the rear axle until the truck is sitting level.

With 440-660 lbs. of hitch weight and something like a 3:1  or 4:1 ratio between the truck wheelbase and the distance of the hitch behind the rear axle, weight transfer off of the front end may not be a problem.

If you're worried, take the truck and trailer to a scale and find out what's happening.  Get individual axle weights with the trailer attached, then repeat the process with the truck by itself.

If you see a significant reduction in front axle weight with the trailer attached, consider getting an equalizing hitch and tension the equalizing bars until the front end weight returns to normal. 

From Equal-I-zer website (other brands are similar): Getting Things Ready

Ideally, when installing or adjusting the hitch, the tow vehicle and trailer should be loaded just as they will be while traveling. This includes full propane and fresh water tanks, and any other cargo (passengers & gear) the tow vehicle or trailer will carry, including ATVs for toy haulers. If fully-loaded is not possible, set the hitch up for the trailer ?as-is,? and make adjustments later if needed.

Tow vehicle ?auto-level? systems should also be disabled or turned off temporarily. Suspension air bags should be inflated to their desired towing psi before hitch setup. Inflating rear axle air bags after setup will most likely decrease the amount of weight distribution provided by the hitch.

Park the trailer and tow vehicle on level ground and in line with each other. Chock and uncouple the trailer. Pull tow vehicle ahead about 5 feet to allow working area and set the parking brake.

https://www.equalizerhitch.com/manuals-guides/manuals/6k-14k-model-owners-manual/installation/getting-things-ready

I understand how the hitch system works, my only problem is with the auto level system. It looks as though that will be a problem for me. I'm not too sure how it will ride with the auto level disconnected. Could be no rear suspension at all.

Right. Auto-level does interfere with WD systems. By itself it may transfer a small amount of weight forward as it raises the back end, but it is not doing the same as a WD hitch.  Is there any way to turn off the auto-level on your Envoy?

I've not owned an Envoy, but I had a Caddy with air auto-level and it was an assist to the spring suspension, not in lieu of it. If the spring suspension sagged even a little, the air came on the raise the back end up again. Then if the back end started to get a little high later, it bled off air to bring it back done. I think that's the part that defeats WD.  We towed a travel trailer with that Caddy for a few months and the auto-level was always cycling and we had to turn it off.

welmack said:

I understand how the hitch system works, my only problem is with the auto level system. It looks as though that will be a problem for me. I'm not too sure how it will ride with the auto level disconnected. Could be no rear suspension at all.

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You cannot turn the system off without wrecking the bags and on the Envoy they are brutally expensive as there is no aftermarket system available. Your only option is weight management as suggested a dist hitch will put undue stress on the bags, try towing without it. The Envoy is built on a truck frame and as a tow vehicle generally is quite good - not sure on your specific trailer though, i have pulled a 22ft 3500lbs boat with one and it was a little underpowered but handled it ok not great but ok

Thanks Gary. I don't know of any way to disable the auto leveling system. This is not an air assist, the bags are the rear system.

thanks to steveblonde also. I knew the Envoy was built on a truck chassis. I like everything about the Envoy and will just have to properly load the trailer and give it a shot. I have the straight 6 which delivers 275 hp with 275 ft/lb torque. Another thing I like is the 4 wheel disc brakes.

One good thing about the trailer is that it is a 2 axle rig which will help reduce the up and down on the hitch. Looks as though I will have to try with a regular hitch.

We will be headed from Tx to Mn in May but will try to get in a short trip somewhere before the long trip. I will keep everyone informed about how our experiences go. Thanks to all who commented.

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welmack said:

Thanks Gary. I don't know of any way to disable the auto leveling system. This is not an air assist, the bags are the rear system.

Click to expand...

Auto leveling makes an equalizing hitch a little harder to initially set up properly, but it can be done.

With the truck and trailer fully loaded, hitch up, adjust the equalizing bars and wait for the auto-leveling to compensate for the extra weight on the rear axle.  As the rear of the vehicle raises up, the tension on the equalizing bars and the amount of weight they transfer forward will decrease.

After the airbags have inflated, take the rig over the scale and see how much weight is being transferred forward. If it's not enough, increase the tension on the equalizing bars.  Wait for the suspension to compensate for this adjustment and weigh again.

Once you get the right setting, just duplicate it the next time you hitch up.

The equalizing bars do increase the weight across the rear axle, but this shouldn't harm the airbags unless you were too  close to the rear suspension weight limit to begin with.

Thanks Lou. Will the WDH lower the amount of travel in the rear suspension enough that the compressor won't be chasing the leveler? I won't be heavy enough to damage the bags.

It should be pretty easy with an adjustable receiver to get the trailer to pull level or very near so by moving the ball up and down, my truck hardly squatted down when I hooked up. 

My biggest reason for having an equalizer hitch was for side to side sway control.  Even though my truck is a big one and my trailer is over 10K loaded, when Semi's whip by you at 70+ they will pull the trailer side ways toward them.  That is somewhat akin to the feeling of sea sickness in your stomach as you watch and feel it happen as you go down the road.

With the Equalizer you can adjust the pressure on the front wheels of the truck up or down by adding or removing washers that provide down angle pressure on the arms and the arms provide side to side friction to keep the trailer from moving side to side.

welmack said:

Thanks Lou. Will the WDH lower the amount of travel in the rear suspension enough that the compressor won't be chasing the leveler? I won't be heavy enough to damage the bags.

Click to expand...

The compressor WILL chase the leveling bars, that's why you have to double check the amount of weight being transferred forward after the airbags inflate.

But once you reach the proper setting (enough tension to transfer weight forward after the airbags lift the rear end) you won't have any reduction in the rear axle suspension travel.  That's what the airbags preserve when they inflate and raise the rear back to it's proper ride height.  You just have to make sure the change in height leaves enough tension in the equalizing bars to transfer weight forward.

Time constants in the compressor and release valve controls prevent momentary changes in height from inflating or deflating the bags.  Otherwise the compressor would kick in every time you go over a bump in the road.

welmack said:

I understand how the hitch system works, my only problem is with the auto level system. It looks as though that will be a problem for me. I'm not too sure how it will ride with the auto level disconnected. Could be no rear suspension at all.

Click to expand...

Reread the information in the link I provided.

Perhaps you didn't understand the meaning of "Tow vehicle ?auto-level? systems should also be disabled or turned off temporarily."

Again: "TEMPORARILY"

From lynnmor

Perhaps you didn't understand the meaning of "Tow vehicle ?auto-level? systems should also be disabled or turned off temporarily.

Click to expand...

Perhaps you missed my meaning

Thanks Gary. I don't know of any way to disable the auto leveling system. This is not an air assist, the bags are the rear system.

Click to expand...

. There is NO temporary turn off or disable.

Thanks Lou, this sounds like another part of the answer I have been looking for.