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Tow Vehicle Rear End Sag

4evertravel
Explorer
Explorer
We recently upgraded our tow vehicle, so now the hitch and ball sit much higher than the coupler on the tongue of the trailer (when its level). After hooking it up and putting all the trailer weight on the tow vehicle, and not the jack, the rear end sags. We have a weight distribution hitch, but that doesn't seem to help. What could cause this, and how do we fix it?
Thanks-
23 REPLIES 23

donut_dave
Explorer
Explorer
start by lowering the ball. then reposition you weight distributing hitch according to hitch requirements. then you should be fine.

Boomerweps
Explorer
Explorer
Lynnmor wrote:
Boomerweps wrote:

For MY hitch, the top of the hitch ball is supposed to be one inch above the inside top of the coupler when the trailer is level and no load on/in the truck.


That is a starting point, your truck might sag considerably or hardly at all. The OP needs to set up his hitch to return the front to the correct level, then if the rear is way too low, only more spring will help. Air bags are one kind of spring.


My statement was a reply to setting them the same height before connecting & adjusting the WDH.
2019 Wolf Pup 16 BHS Limited, axle flipped
2019 F150 4x4 SCrew SB STX 5.0 3.55 factory tow package, 7000#GVWR, 1990 CC Tow mirrors, ITBC, SumoSprings,

kellem
Explorer
Explorer
No, I'm only eliminating the need for airbags on a bumper pull trailer.

My Reese DC is setup properly with the proper trunnion bars to match tounge weight.

I can also use my headlights at night without illuminating the clouds, truck and trailer sit level without compromising safe handling.

That said, I do pull a 7300 lb trailer with a 3/4 ton truck.

I've mounted this WDH onto 4 different trailers and upgraded trunnion bars twice ,adjusted per spec and always end up extremely close to level, truck and trailer.

Wish you and your family safe towing.

Lynnmor
Explorer
Explorer
kellem wrote:
Lynnmor wrote:
kellem wrote:
Nope, while the spring bars on a formidable WDH returns weight to the front, it also mitigates rear sag.....airbags shouldn't be a necessity but rather heavier spring/trunnion bars.


So you just keep adding weight distribution till the rear comes up to where it started? Yeah, Right.


Yeah, it's called weight distribution.
4 trailers and each rode level and each application absorbed the tounge weight perfectly.
What's the purpose of investing in a WDH that sags?


Here is what my owners manual says:

When hooking-up a trailer using a weight-distributing hitch, always use the following procedure:
1.Park the loaded vehicle, without the trailer, on a level surface.
2.Measure the height to the top of your vehicle's front wheel opening on the fender. This is H1.
3.Attach the loaded trailer to your vehicle without the weight-distributing bars connected.
4.Measure the height to the top of your vehicle's front wheel opening on the fender a second time. This is H2.
5.Install and adjust the tension in the weight-distributing bars so that the height of your vehicle's front wheel opening on the fender is approximately halfway between H1 and H2.
6.Check that the trailer is level or slightly nose down toward your vehicle. If not,adjust the ball height accordingly and repeat Steps 2-6.

Now I guess you recommend ignoring your owners manual and continue to crank up the weight distribution till traction is severely reduced. Giving advice is fine, just don't tell people to do things that are dangerous and opposite of the manufacturers instructions.

kellem
Explorer
Explorer
Lynnmor wrote:
kellem wrote:
Nope, while the spring bars on a formidable WDH returns weight to the front, it also mitigates rear sag.....airbags shouldn't be a necessity but rather heavier spring/trunnion bars.


So you just keep adding weight distribution till the rear comes up to where it started? Yeah, Right.


Yeah, it's called weight distribution.
4 trailers and each rode level and each application absorbed the tounge weight perfectly.
What's the purpose of investing in a WDH that sags?

Lynnmor
Explorer
Explorer
kellem wrote:
Nope, while the spring bars on a formidable WDH returns weight to the front, it also mitigates rear sag.....airbags shouldn't be a necessity but rather heavier spring/trunnion bars.


So you just keep adding weight distribution till the rear comes up to where it started? Yeah, Right.

kellem
Explorer
Explorer
Nope, while the spring bars on a formidable WDH returns weight to the front, it also mitigates rear sag.....airbags shouldn't be a necessity but rather heavier spring/trunnion bars.

Lynnmor
Explorer
Explorer
Boomerweps wrote:

For MY hitch, the top of the hitch ball is supposed to be one inch above the inside top of the coupler when the trailer is level and no load on/in the truck.


That is a starting point, your truck might sag considerably or hardly at all. The OP needs to set up his hitch to return the front to the correct level, then if the rear is way too low, only more spring will help. Air bags are one kind of spring.

Boomerweps
Explorer
Explorer
rexlion wrote:
4evertravel wrote:
We recently upgraded our tow vehicle, so now the hitch and ball sit much higher than the coupler on the tongue of the trailer (when its level). After hooking it up and putting all the trailer weight on the tow vehicle, and not the jack, the rear end sags. We have a weight distribution hitch, but that doesn't seem to help. What could cause this, and how do we fix it?
Thanks-
First off, you want to change your WDHitch configuration so its ball sits at the proper level (when unhooked), same height as the trailer tongue when level.

For MY hitch, the top of the hitch ball is supposed to be one inch above the inside top of the coupler when the trailer is level and no load on/in the truck.
2019 Wolf Pup 16 BHS Limited, axle flipped
2019 F150 4x4 SCrew SB STX 5.0 3.55 factory tow package, 7000#GVWR, 1990 CC Tow mirrors, ITBC, SumoSprings,

Grit_dog
Navigator
Navigator
TomG2 wrote:
To the OP: Obviously, you have asked a big question and are getting lots of opinions. Give them all a big assist by posting ACTUAL weights, ratings, and measurements. Without them, it is just guessing and can actually be dangerous.


Or maybe itโ€™s better that the OP doesnโ€™t. Iโ€™d bet $20 that if he does, the rvnet weight cops will just nuke the thread.
2016 Ram 2500, MotorOps.ca EFIlive tuned, 5โ€ turbo back, 6" lift on 37s
2017 Heartland Torque T29 - Sold.
Couple of Arctic Fox TCs - Sold

ppine
Explorer II
Explorer II
First you need to find a hitch ball that sits at the right height so your trailer is more level. More drop is needed.

Then you need to properly adjust your weight distributing hitch.
Get some help if you are still having problems.

TomG2
Explorer
Explorer
I have owned and towed with a dozen late model pickups and none said that everything had to be level. The last couple said to restore 50% of front axle reduction. They also gave ratings to observe.

kellem
Explorer
Explorer
Yes need some more info to give proper advice.
You'll likely have to adjust the hitch and perhaps upgrade the trunnion bars depending on WDH.

The goal is to have TV and trailer as level as possible and a properly adjusted WDH can accomplish this.

TomG2
Explorer
Explorer
To the OP: Obviously, you have asked a big question and are getting lots of opinions. Give them all a big assist by posting ACTUAL weights, ratings, and measurements. Without them, it is just guessing and can actually be dangerous.