Airbag Suspension Options Ford Expedition

IdaD wrote:
etrailer has a coil sumo spring that looks like it would fit. Not air but maybe the same result. I've never used one and hadn't ever seen anything designed quite like it but you could check it out.

Well, this was the only real answer to the OPs question after 2 plus pages of "if you look on p173 line 17 it CLERLY states to adjust the Fluux capacitor to 77.3% of minimum magnetoidal influence during the summer solstice at exactly 1:33pm....."

Looks like sumos are about the only available option at this point. But I wonder, with the height and diameter of the coils, you may be able to match up some front axle coil spring assist bags that go inside the springs. More disassembly required, but adjustable.

Groover wrote:

Lynnmor wrote:

Groover wrote:

As much as I would like to agree with you the Ford manual says that if the front end rises 1" you use the hitch to bring it back down to a 3/4" rise. I don't understand it or like it but they must have a reason. Due to that I have installed air bags to help level the truck so that my headlights are pointed the right direction and I won't drag the rear as much.

That is not what is in the owners manual. Please read page 208 and you will find that you should bring the front back down by half of what it raised.

Ford very clearly says to use a 25% correction factor on page 34 for the F150 of this 2017 towing guide, the other vehicles are 50%:
https://www.fleet.ford.com/truckbbas/topics/2017/2017_RV_Trailer_Towing_Guide.pdf

CALCULATION EXAMPLE
Vehicle = F-150
H1 = 37 inches
H2 = 38 inches
Correction Factor = 25%
Height Change = 38" - 37" = 1 inch
Reduction =
Amount = 1" x 25% = .25 inches

Height =
Change = 38" - .25" = 37.75 inches

Target Height = 37.75 inches

Personally, I would still like to see at least 75% to 100%. That is still going leave most of the tongue weight on the rear axle which affects your steering by rocking the castor angle back some but it would get more weight on the front brakes which are generally the biggest brakes on trucks without dual rear tires.

First, we are discussing an Expedition, not a truck.

Second, the 25% figure is not a recommendation anywhere that I can find. 50% to 100% is common recommendations from hitch and vehicle makers.

Third, that is a sales brochure possibly written by non-technical people.

Forth, read the owners manual, page 208.

Lynnmor wrote:

Groover wrote:

As much as I would like to agree with you the Ford manual says that if the front end rises 1" you use the hitch to bring it back down to a 3/4" rise. I don't understand it or like it but they must have a reason. Due to that I have installed air bags to help level the truck so that my headlights are pointed the right direction and I won't drag the rear as much.

That is not what is in the owners manual. Please read page 208 and you will find that you should bring the front back down by half of what it raised.

Ford very clearly says to use a 25% correction factor on page 34 for the F150 of this 2017 towing guide, the other vehicles are 50%:
https://www.fleet.ford.com/truckbbas/topics/2017/2017_RV_Trailer_Towing_Guide.pdf

CALCULATION EXAMPLE
Vehicle = F-150
H1 = 37 inches
H2 = 38 inches
Correction Factor = 25%
Height Change = 38" - 37" = 1 inch
Reduction =
Amount = 1" x 25% = .25 inches

Height =
Change = 38" - .25" = 37.75 inches

Target Height = 37.75 inches

Personally, I would still like to see at least 75% to 100%. That is still going leave most of the tongue weight on the rear axle which affects your steering by rocking the castor angle back some but it would get more weight on the front brakes which are generally the biggest brakes on trucks without dual rear tires.

Groover wrote:

As much as I would like to agree with you the Ford manual says that if the front end rises 1" you use the hitch to bring it back down to a 3/4" rise. I don't understand it or like it but they must have a reason. Due to that I have installed air bags to help level the truck so that my headlights are pointed the right direction and I won't drag the rear as much.

That is not what is in the owners manual. Please read page 208 and you will find that you should bring the front back down by half of what it raised.

Ford recommends 50% FALR for the 17 Expy. The reason is to maintain proper amount of understeer during cornering since adding any amount of WD will reduce it.

DavidP wrote:
My truck sits level without airbags and I agree you should not use airbags to compensate for rear end sag when used with a WDH. I use them because they do add lateral stability and stiffen up the rear suspension. They will also take the bounce out in very uneven/rolling sections of road.

In some cases even with a properly set up WDH many experience an inch or so of sag. This too is a good application for airbags. The key for the OP is to get the front-end of the TV within 1/4 inch of unloaded ride height. As long as you have that using airbags to get a little sag out of the rear is fine. The key is also to set the WDH with airbags already aired up to determined PSI. Air up the bags and then set the trailer down and cinch up the bars. Do not set the bars and then air up, this will unload the WDH.

I also like airbags since I pull a 21 foot boat as well. Airbags can be a great addition when used properly.

As much as I would like to agree with you the Ford manual says that if the front end rises 1" you use the hitch to bring it back down to a 3/4" rise. I don't understand it or like it but they must have a reason. Due to that I have installed air bags to help level the truck so that my headlights are pointed the right direction and I won't drag the rear as much.

My truck sits level without airbags and I agree you should not use airbags to compensate for rear end sag when used with a WDH. I use them because they do add lateral stability and stiffen up the rear suspension. They will also take the bounce out in very uneven/rolling sections of road.

In some cases even with a properly set up WDH many experience an inch or so of sag. This too is a good application for airbags. The key for the OP is to get the front-end of the TV within 1/4 inch of unloaded ride height. As long as you have that using airbags to get a little sag out of the rear is fine. The key is also to set the WDH with airbags already aired up to determined PSI. Air up the bags and then set the trailer down and cinch up the bars. Do not set the bars and then air up, this will unload the WDH.

I also like airbags since I pull a 21 foot boat as well. Airbags can be a great addition when used properly.

APT wrote:

I purchased it, despite being appropriately connected to a weight distribution hitch

Connected is not the same as properly adjusted. A WDH returns lost weight to the front axle. Rear suspension aids including air bags do not. Spend $15 at a CAT scale first. Take 3 passes with 3 pads.

Truck front axle, Truck rear axle, trailer axles
Truck only, Truck with trailer without WD bars, truck with trailer with WD bars.

My previous tow vehicle was 0-500 pounds over GVWR for every RVing trip. The rear end never sagged with my WDH fully restoring front axle weight. The combination was comfortable and stable, albeit a little slow at times. It seems unlikely you should need any rear suspension aid.

I used to adjust my hitches to "fully restore front axle weight" and agree that the vehicle drives well that way but the manual says not to do that on my 2016 F150. It says to only restore 1/4 of the weight. The only thing that I can figure is that since the factory hitch is actually a glorified bumper hitch they just want you to take some of the stress off of the bolts holding the bumper on. If I could find a hitch with stringers attached to the frame that doesn't drop way down below the bumper I would upgrade and go back to putting more weight on the front.

I purchased it, despite being appropriately connected to a weight distribution hitch

Connected is not the same as properly adjusted. A WDH returns lost weight to the front axle. Rear suspension aids including air bags do not. Spend $15 at a CAT scale first. Take 3 passes with 3 pads.

Truck front axle, Truck rear axle, trailer axles
Truck only, Truck with trailer without WD bars, truck with trailer with WD bars.

My previous tow vehicle was 0-500 pounds over GVWR for every RVing trip. The rear end never sagged with my WDH fully restoring front axle weight. The combination was comfortable and stable, albeit a little slow at times. It seems unlikely you should need any rear suspension aid.

Measure height and width of coil. Good chance the coil is the same as the 2016 XLT.