Which hd would be better?

[nlambert182]

3500 is the right tool but the ride is noticeably more jarring than the coils on the 2500 (yes, I've driven both). OP's theory about same/similar parts is generally accurate. Airbags a "band-aid"?? I guess we can all have our opinions but I'm pretty sure most of us would be damn happy rolling along in a Prevost diesel pusher chassis riding on nothing but a bunch of "band-aids".

Then, there's always the, "your insurance company will deny an accident claim and you'll go to jail in an accident," argument. Neither one is true but I do get the argument and personally try to stay in compliance.

Commercial trucks, bridge weights and pretty much everything that matters runs off axle weights and IMO those (including tires, of course) are ultimately what's most important to stay safe.

The airbags on commercial trucks and large RVs aren't even close to the same airbags that you can buy off the shelf. I've sold thousands of them.

They are designed to carry the loads where-as these smaller aftermarket bags aren't. There are many valves, air tanks, sensors, etc.. that keep the bags inflated. If your airbags share the same air supply as the brakes, height control valves will try to refill the bags. If they're continuously dumping and the compressor can't keep up, and the pressure drops below 60psi it will trigger the spring brakes. If they're on a separate air supply, you'll get the warning. If you don't stop you're at a large risk of damaging the driveline.

Aftermarket helper bags are designed to be supplemental to the suspension that's already there. They are much less robust and depend on the factory suspension as their failsafe. The average thickness on a semi/rv airbag is about 12mm where these aftermarket helper bags are roughly 4-6mm in thickness.

 

[62Blazer]

I think we are getting confused between the anti-sway bars that are part of the suspension vs the sway control bars that are part of a equalizer hitch. My original post about the Roadmaster sway bar was the add on suspension sway bar for controlling body sway. While the coil spring 2500 has a rear sway bar I don't think the 3500 has one, at least my 06 and 18 didn't. I think HEMIMANN is talking about the sway control in a equalizer hitch and I would sure like to see the regulation that requires it.

I was thinking the same thing. If they are talking about a requirement there is a sway control hitch for the trailer that is the first time I have ever heard this. I've never heard any regulation, requirement, or law that you need anything other than a standard ball hitch to pull a trailer regardless of weight. Sure, WDH and sway control are never a bad idea but don't think it's any federal or state law. Speaking of which, I'm pretty sure the state establishes any laws for this and not the federal government. The comment also stated any trailer that was over 50% of the vehicle weight. That's not a very big trailer. If you have gas powered truck that weighs 7,000 lbs. that means you need a sway control hitch for a 6x12 single axle trailer rated at 3,500 lbs.? I mean, really?

The only regulation or law I have seen concerns trailer brakes. It varies some by states by pretty common to say anything over a 3,000-3,500 lb. trailer requires brakes. Go to any RV or trailer store and find a new trailer sitting on their lot that is bigger than a little single axle trailer that does not have brakes.

 

[62Blazer]

If one is towing a tag-along trailer, using just airbags to level the truck/trailer is a false security, it actually makes the front end of the truck lighter. I've posted a video on this very thing and have had people swear it's nothing more than a sales pitch.
As for a fiver or gooseneck trailer, your correct that one can dial in how the truck handles the load with airbags. We'll leave it at that or the payload police will get their panties in a bunch

I agree that airbags do not replace a WDH in regards to distributing weight on a bumper pull trailer. If I was forced to only have one or the other, I would pick the WDH first. What I am saying is that bags can improve towing performance. Having the rear of the truck squatted way down under a load can cause weird handling. Also soft springs can cause a lot of bouncing. The bag position on a 2500 also decreases side to side sway (personal experience towing with and without bags). This is comparing a truck with no air bags versus one with bags........not comparing bags to WDH.
To be honest I'm not sure how having airbags in a truck to keep it level somehow causes the front end to become significantly lighter as compared to if it was squatted a lot in the rear (again, with no WDH) I know it doesn't transfer weight to the front axle like a WDH. However I don't understand how you can take a truck, hook up a trailer so the rear end squats, than add airbags to level it and the front gets way lighter? I'm not an expert in the field but do have an engineering degree and understand physics. If you look at a side profile of the vehicle and the center of mass, the vertical line showing the weight transfer is typically slightly more towards the rear on a squatted truck....meaning the front would be lighter on a squatted truck and heavier on a level truck. But only by a small amount.

 

[nlambert182]

By themselves airbags won't really add/remove weight from the front axle but what they "can" do is give people a false sense of security whereas they begin overloading even more because it looks level. That scenario does remove more weight from the front end, and without a CAT scale you wouldn't necessarily realize it.

Now, if you couple a WDH WITH airbags but fail to reset the WDH to compensate, then it's possible to decrease front axle weight because once you adjust the airbags, you've removed some of the torsion that the WDH applies to shift the weight.

If you're using the right truck and trailer combination airbags aren't needed at all. If I hook up the camper in my signature below my truck sits level. It's just shy of 10k lbs. There is less than 0.5" of difference between the top of my front tire and my fender. I do run a WDH, but primarily for sway control and not really for weight distribution.

 

[lpennock]

To be honest I'm not sure how having airbags in a truck to keep it level somehow causes the front end to become significantly lighter as compared to if it was squatted a lot in the rear (again, with no WDH) I know it doesn't transfer weight to the front axle like a WDH. However I don't understand how you can take a truck, hook up a trailer so the rear end squats, than add airbags to level it and the front gets way lighter? I'm not an expert in the field but do have an engineering degree and understand physics. If you look at a side profile of the vehicle and the center of mass, the vertical line showing the weight transfer is typically slightly more towards the rear on a squatted truck....meaning the front would be lighter on a squatted truck and heavier on a level truck. But only by a small amount.

The truck in picture has factory air and is NOT running a equalizer hitch. Looked the same loaded an unloaded but the weights were:
Unload Front: 5720 Drive: 5180
Loaded Front 5260 Drive: 6620 Trailer 5100
So as you can see the about 1K of tongue weight unoaded the front by 500 lb.

 

[crash68]

However I don't understand how you can take a truck, hook up a trailer so the rear end squats, than add airbags to level it and the front gets way lighter?

It only applies to when towing a tag-along trailer, but it's physics at work.
Here a video that shows the difference of what happens when leveling a truck with air bags versus a WDH:

The Difference Between Using Weight Distribution and Air Bags to Level Your Load

Fastway engineers Jason Harper and Matt Barnes investigate the difference between using either a rear axle air bag system, or a weight distribution hitch to ...

youtu.be

This does not apply when towing with a fiver or gooseneck unless the hitch is behind the rear axle center line.

 

[nlambert182]

Yep. It's all about placement of the lever. A bumper pull puts a lever force behind the bumper, which raises the front of the truck. The torsion from a WDH pulls up on the tongue and sends some of that weight back to the front axle. With a fiver/GN, the downward force of the trailer is over the axle, so the suspension takes most of that force and the weight taken off the front end is much less.

 

[62Blazer]

The truck in picture has factory air and is NOT running a equalizer hitch. Looked the same loaded an unloaded but the weights were:
Unload Front: 5720 Drive: 5180
Loaded Front 5260 Drive: 6620 Trailer 5100
So as you can see the about 1K of tongue weight unoaded the front by 500 lb.
View attachment 574248

I understand, but that is not the point I'm trying to get across. In your example the reason the front is lighter is because you have a trailer with 1,000 lbs. of tongue weight on it. The front being lighter has nothing to do with whether it has airbags or not. Remove the airbags and the front axle is still 500 lbs. lighter. I never said airbags somehow stop weight transfer or anything.
Again, my point is that airbags do not magically make the front end "lighter"... Airbags mainly just keep the rear suspension from squatting as much and make it feel firmer (less squishy) when towing.

 

[62Blazer]

It only applies to when towing a tag-along trailer, but it's physics at work.
Here a video that shows the difference of what happens when leveling a truck with air bags versus a WDH:

The Difference Between Using Weight Distribution and Air Bags to Level Your Load

Fastway engineers Jason Harper and Matt Barnes investigate the difference between using either a rear axle air bag system, or a weight distribution hitch to ...

youtu.be

This does not apply when towing with a fiver or gooseneck unless the hitch is behind the rear axle center line.

I completely understand the difference, and again that is not the point I'm trying to get across. My response was based on somebody saying that if the rear of the truck was squatted because of a load, and you put airbags in to raise the rear suspension back up, it somehow made the front axle lighter.

 

[Grams]

It says you can add air bags to overcome the lighter spring weight

Air bags do NOT increase weight capacity.

They Do help prevent the headlights from blinding on-coming vehicles by altering the ride-angle… But they do absolutely Nothing to increase the weight or payload capacity of the vehicle.

BTDT

 

[lpennock]

I understand, but that is not the point I'm trying to get across. In your example the reason the front is lighter is because you have a trailer with 1,000 lbs. of tongue weight on it. The front being lighter has nothing to do with whether it has airbags or not. Remove the airbags and the front axle is still 500 lbs. lighter. I never said airbags somehow stop weight transfer or anything.
Again, my point is that airbags do not magically make the front end "lighter"... Airbags mainly just keep the rear suspension from squatting as much and make it feel firmer (less squishy) when towing.

Actually I was agreeing with you. The only thing the bags did was keep the back from sagging the weight would have came off the front axle regardless unless a WD hitch was used.

 

[crash68]

My response was based on somebody saying that if the rear of the truck was squatted because of a load, and you put airbags in to raise the rear suspension back up, it somehow made the front axle lighter.

The way I reading this is you didn't bother to watch the video. Dropping 1000 lbs tongue on the rear of the truck not only squats the truck but lightens the front axle. Using airbags to level the truck further lightens the front axle. The video spells this out in black and white(picture from the video):

 

[62Blazer]

The way I reading this is you didn't bother to watch the video. Dropping 1000 lbs tongue on the rear of the truck not only squats the truck but lightens the front axle. Using airbags to level the truck further lightens the front axle. The video spells this out in black and white(picture from the video): View attachment 574505

I did watch the video. Sorry, I don't consider 25 lbs. significantly different, especially considering you are looking at 3,650 lbs. . You are talking 0.68% difference. The scales they use are only accurate to +/-1% of the measured weight, or +/-36.5 lbs. (range of 73 lbs.). Not only is the weight they report insignificant, it's also unreliable because it's less than the accuracy of the scales and there is only one data point. It's completely reasonable if you reset the whole system and did the test over that the front would now weigh 25 lbs. more.
I'm just not making this stuff up......I'm an engineer and do testing all the time. If I recommend making a change at work based on this test setup (insignificant difference, that difference is less than the accuracy of the test equipment, and only one data point) my boss would laugh me out of the room........