Installing air bags when you have on board scale

[SG1065]

Just wondering if anyone has had any luck installing air bags on their F-150 with the onboard scale option? Info and pics would be greatly appreciated

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[towpro]

I would expect air bags would cause the scales to now work correct since the onboard scale works on math my measureing how far your truck drops per pound of load against a know (factory) suspension.

 

[Snakebitten]

Any of the legitimate Payload carrying enhancements are sure to affect the scales for obvious reasons. But I've given it some thought and with little effort I could do my own personal calibration.

All I need is some known weights to use and then do the math.

For example, if I had a few bags of feed, or maybe some concrete bags....... I could add the known weight and record it next to the indicated weight. Quickly the proper function would reveal itself. Similar to a speedometer error due to taller tires.

I installed RAS on my truck with CCD/Scales.
I actually use them to "tune" the factory damping to my liking, since the factory damping is too conservative. (soft)
But they also would naturally affect the height sensors calibration for measuring weight because the truck will sag less per pound.

Again, I'll just throw 400lbs in the bed and see what the scales think I added. I suspect it will underestimate the weight by some %.

 

[Kanuck]

Any of the legitimate Payload carrying enhancements are sure to affect the scales for obvious reasons. But I've given it some thought and with little effort I could do my own personal calibration.

All I need is some known weights to use and then do the math.

For example, if I had a few bags of feed, or maybe some concrete bags....... I could add the known weight and record it next to the indicated weight. Quickly the proper function would reveal itself. Similar to a speedometer error due to taller tires.

I installed RAS on my truck with CCD/Scales.
I actually use them to "tune" the factory damping to my liking, since the factory damping is too conservative. (soft)
But they also would naturally affect the height sensors calibration for measuring weight because the truck will sag less per pound.

Again, I'll just throw 400lbs in the bed and see what the scales think I added. I suspect it will underestimate the weight by some %.

That would work if you carried approx the same weight with the same air pressure in the RAS, same amount of sag. But as the weights go up, so does the amount of air added to the RAS which would cause less of a sag and the truck would not give a correct reading.

 

[Buyer2021]

Just curious (I don't have it), do onboard scales show the same weight no matter where the load is placed?

I ask because I know from experience that 600# of feed placed tight against the front of the bed vs placed against the tailgate vs 600# on the hitch all result in different amounts of 'sag' (+/-) at the F&R axles.
_____________

Insofar as use with air bags, does it make sense to take 'weight measurements' before inflating the bags so the truck's 'natural sag' is unaffected and provides 'true' weight, then inflate the bags to achieve the desired 'trim'?

Admitting, not having the option, I'm not at all sure how / why onboard scales are intended to be used (when weights are critical for me I still use old-school external scales).

Just here to learn

 

[Snakebitten]

RAS isn't air driven. It's basically an adjustable leaf spring damper. Or you could look at it as an adjustable leaf spring weight?

Either way, you are correct that I would have to make the effort to "map" the formula for various RAS settings. But it's not an infinite thing in my application. I might have 2 or 3 settings that I would set the RAS 2 and then use the appropriate formula.

Admittedly I'm not expecting the scales to be accurate to the pound. They aren't, in my opinion anyways since they aren't really scales in the strictest sense. They are a calculation based on a heighth sensor.

 

[Kanuck]

RAS isn't air driven. It's basically an adjustable leaf spring damper. Or you could look at it as an adjustable leaf spring weight?

Either way, you are correct that I would have to make the effort to "map" the formula for various RAS settings. But it's not an infinite thing in my application. I might have 2 or 3 settings that I would set the RAS 2 and then use the appropriate formula.

Admittedly I'm not expecting the scales to be accurate to the pound. They aren't, in my opinion anyways since they aren't really scales in the strictest sense. They are a calculation based on a heighth sensor.

It was a point I thought I should bring up so others would take it into consideration. Before I was an electrician, I worked for a scale company for 13 years. The air bags could be used to give a approx weight by the air pressure required to bring the truck level. Example; every 1 lb of air pressure would off set 5 lbs of weight = 20 psi would equal 20 x 5 = 100 lbs. It would not be real accurate but would give you and pretty close idea as to your tongue weight.

Edit: You would have to measure the height of a fixed point on the truck, say the top of the bumper, with enough to just fill the bags air pressure (2 or 3 PSI), apply the load, and see how much air pressure it takes to return to that level.

 

[Snakebitten]

Just curious (I don't have it), do onboard scales show the same weight no matter where the load is placed?

I ask because I know from experience that 600# of feed placed tight against the front of the bed vs placed against the tailgate vs 600# on the hitch all result in different amounts of 'sag' (+/-) at the F&R axles.
_____________

Insofar as use with air bags, does it make sense to take 'weight measurements' before inflating the bags so the truck's 'natural sag' is unaffected and provides 'true' weight, then inflate the bags to achieve the desired 'trim'?

Admitting, not having the option, I'm not at all sure how / why onboard scales are intended to be used (when weights are critical for me I still use old-school external scales).

Just here to learn

You're on the right track.
If you have a couple of big guys climb up in the bed and stand in the front of the bed and then the back of the bed it does move the scale just like you imagined.

And if you pumped air into Airbags you will see the weight reduce on the scales because you raised the height sensor lever.

The VDM module is the controller for the feature and based on the service manual it's apparently possible to raise the truck enough to throw a DTC, since you would move the height sensor lever outside its expected parameters.
I intended to test what the limits are but haven't gotten around to it.

FDRS also has a calibration routine that I suspect could be used to "zero out" the parameters if you were to modify your suspension in a way that affected the factory zero point.

It's all rather fascinating to me. I've enjoyed digging in as little as I have

 

[DBL R]

Can you run airbags with CCD? Does it affect the CCD system at all?

 

[Snakebitten]

You can. But yes, it would act as a second source of damping. (potentially a GOOD thing, in my opinion)
It's exactly why I installed the RAS, to be honest.

My real hope is for one of the Forscan geniuses to crack the values of the VDM module. They already have mapped it!

If they do ever figure out the AsBuilt values then hypothetically you could edit the CCD damping values to your liking. I'm really looking forward to that. I believe it's inevitable, but I'm an optimist.

 

[LD50]

The VDM module is the controller for the feature and based on the service manual it's apparently possible to raise the truck enough to throw a DTC, since you would move the height sensor lever outside its expected parameters.
I intended to test what the limits are but haven't gotten around to it.

Does yours have a height sensor lever? I've got CCD and scales as well and it definitely does not have them mounted to the leaf pack like I have seen in some photos. I assume that the CCD shocks are giving the VDM the necessary information.

I also just started using the RAS that I had for my last truck and it is an improvement but I'm considering switching over to airbags. Most of the airbag kits that are compatible mention they don't work with CCD because of the ride height sensors. It made me wonder if there was a change in how the ride height sensing was handled between the '21's and '22's.

I know you're not supposed to run most of the airbags with less than 5 psi of air in them but I can't see it being an issue to bleed them down to 0 psi to get a measurement from the onboard scales. My guess is that they would have little or no effect on the measurement in that state. You could also use the scale function as a gauge to adjust the truck back to an unloaded ride height.

 

[Snakebitten]

@LD50

Good catch. Yes, if you have CCD and scales, the height sensor is in the casing that surrounds the shock, so it's not a lever type height sensor in the rear.

I don't think the 5lb minimum will be much of an issue with the CCD/scales system. It would be interesting to view in real time how the scales are affected as you raise the truck, but I don't think 5lbs would raise it significantly.

I adjusted the RAS less than the 1mm spring spacing recommended for carrying weight. Instead, I adjusted them just enough to get the rear end on an empty truck to no longer do the double bounce over railroad tracks or sharp bumps. (That drives me crazy and I was really disappointed to find that Ford didn't tune that out with active suspension. Amazing they intentionally tuned the CCD to be so similar to the oem analog shocks. It's a truck!)

So RAS only lifted the rear about 1/4" with my current settings and so scales are unaffected

 

[DBL R]

Does yours have a height sensor lever? I've got CCD and scales as well and it definitely does not have them mounted to the leaf pack like I have seen in some photos. I assume that the CCD shocks are giving the VDM the necessary information.

I also just started using the RAS that I had for my last truck and it is an improvement but I'm considering switching over to airbags. Most of the airbag kits that are compatible mention they don't work with CCD because of the ride height sensors. It made me wonder if there was a change in how the ride height sensing was handled between the '21's and '22's.

I know you're not supposed to run most of the airbags with less than 5 psi of air in them but I can't see it being an issue to bleed them down to 0 psi to get a measurement from the onboard scales. My guess is that they would have little or no effect on the measurement in that state. You could also use the scale function as a gauge to adjust the truck back to an unloaded ride height.

https://www.jackit.com/air-88389.html

Airlifts website notes the ability to run without air pressure https://www.airliftcompany.com/products/air-springs/loadlifter-5000-ultimate/

I plan on getting these since they have an internal bumper. Can get away without running air. May work well for those with scales.
I plan on getting these since they have an internal bumper. Can get away without running air. May work well for those with scales.

 

[LD50]

https://www.jackit.com/air-88389.html

Airlifts website notes the ability to run without air pressure https://www.airliftcompany.com/products/air-springs/loadlifter-5000-ultimate/

I plan on getting these since they have an internal bumper. Can get away without running air. May work well for those with scales.
I plan on getting these since they have an internal bumper. Can get away without running air. May work well for those with scales.

I've read the airlift install instructions several times and it does say 5 PSI minimum at the end. I'm not too worried about it either way since the only time I'd deflate them to 0 would be for using the scale or tongue weight while stationary.

I'm kind of leaning towards a system with no internal jounce stopper right now. I keep seeing comments about harsh rides even when unloaded with the jounce stopper. I'm also favoring the ride-rites at the moment as the installation seems much simpler than the airlifts. I'm not a fan of moving ABS lines and cutting mounting brackets. I'm not worried about being able to do it myself, but If I decide to take them off, I want to be able to go back to factory configuration without any modifications.

@LD50

Good catch. Yes, if you have CCD and scales, the height sensor is in the casing that surrounds the shock, so it's not a lever type height sensor in the rear.

I don't think the 5lb minimum will be much of an issue with the CCD/scales system. It would be interesting to view in real time how the scales are affected as you raise the truck, but I don't think 5lbs would raise it significantly.

I adjusted the RAS less than the 1mm spring spacing recommended for carrying weight. Instead, I adjusted them just enough to get the rear end on an empty truck to no longer do the double bounce over railroad tracks or sharp bumps. (That drives me crazy and I was really disappointed to find that Ford didn't tune that out with active suspension. Amazing they intentionally tuned the CCD to be so similar to the oem analog shocks. It's a truck!)

So RAS only lifted the rear about 1/4" with my current settings and so scales are unaffected
[/QUOTE]

I think I'm running mine a little tighter than you are only because I'm mainly using them to reduce sag while towing. I noticed about a 75 pound difference in the scale measurement on my boat trailer which has a hitch weight of around 450 pounds and gross weight of around 7800.

 

[DBL R]

I've read the airlift install instructions several times and it does say 5 PSI minimum at the end. I'm not too worried about it either way since the only time I'd deflate them to 0 would be for using the scale or tongue weight while stationary.

I'm kind of leaning towards a system with no internal jounce stopper right now. I keep seeing comments about harsh rides even when unloaded with the jounce stopper. I'm also favoring the ride-rites at the moment as the installation seems much simpler than the airlifts. I'm not a fan of moving ABS lines and cutting mounting brackets. I'm not worried about being able to do it myself, but If I decide to take them off, I want to be able to go back to factory configuration without any modifications.

@LD50

Good catch. Yes, if you have CCD and scales, the height sensor is in the casing that surrounds the shock, so it's not a lever type height sensor in the rear.

I don't think the 5lb minimum will be much of an issue with the CCD/scales system. It would be interesting to view in real time how the scales are affected as you raise the truck, but I don't think 5lbs would raise it significantly.

I adjusted the RAS less than the 1mm spring spacing recommended for carrying weight. Instead, I adjusted them just enough to get the rear end on an empty truck to no longer do the double bounce over railroad tracks or sharp bumps. (That drives me crazy and I was really disappointed to find that Ford didn't tune that out with active suspension. Amazing they intentionally tuned the CCD to be so similar to the oem analog shocks. It's a truck!)

So RAS only lifted the rear about 1/4" with my current settings and so scales are unaffected

I think I'm running mine a little tighter than you are only because I'm mainly using them to reduce sag while towing. I noticed about a 75 pound difference in the scale measurement on my boat trailer which has a hitch weight of around 450 pounds and gross weight of around 7800.
[/QUOTE]

I appreciate the info. I’ll have to take a look at the ride rite’s.

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