I just want to throw my 2 cents in here. I have been towing my whole life. I grew up on a farm and I have driven just about everything you can name.
Strictly from personal experience with 1500-3500 trucks:. Springs have given me and my dad good results on 1500 series trucks. On the larger pickups, not so much. Adding helpers works to an extent. But the helpers that dont affect the stock ride only really kivk in when it's overloaded. Progressive and varible rate springs, never really worked well.
Even though, you don't want them, proper airbags is the way to go. Properly installed, they never need maintenance, and are infinitely adjustable. Whereas with a spring, you get what you got. They can be changed for specific complaints. I also own my shop, and I rarely recommend springs. I don't understand why you have been on the receiving end of so much negativity regarding airbags. It almost seems like a Ford vs. Chevy argument, and your personal emotions are clouding your ability to view all options dispassionately.

I am not trying to offend you, and I am not trying to make you angry.

That being said. My advice would be find a good shop. Tell them what you want. When they suggest a spring fix, ask them if it doesn't work and you don't like it or are not happy with it, will they remove it and try something else free of charge. Get it in writing.

If you are near the GA/SC border, I can let you drive three very similar truck with the same load (camper) and three different options: helper springs, progressive springs, and a simple airbag setup.

Cheers mate!

 

Don't think you offended anyone, certainly not me. I have no personal aversion to airbags, would like to avoid that particular expense, but your experience is a valid contribution to the forum discussion... The only complaints ive heard consistantly regarding airbags is the side to side sway issue, maybe you can comment on that a bit.

 

I'm certainly not offended either. No worries there. Discussion is definitely welcome.

Side-to-side sway is one issue I constantly struggled with regarding air bags on a previous rig. The bags were *NOT* plumbed together - each had their own line. I installed some stout shocks as well as a beefy anti-sway bar. Neither rectified the problem. Helper springs on my current rig results in a MUCH more stable ride in this regard.

Based on my experience, I'll likely never go the air bag route again. Just my personal preference. Your mileage may vary!

 

For the purpose of this discussion, let's limit this to 3/4 and 1 ton trucks. Semi's use airbags in a different manner.

If you overinflate the air bag, you completely swap the role of airbags and springs. The way your truck is designed is for the spring to carry the weight, and the bag to "help" the spring. When overinflated, the airbag takes on the load, and the spring helps. The springs have very little movement other than their vertical travel. Vehicle sway can be controlled because it becomes a function of uneven vertical travel in two parallel paths. A sway bar can easily fix that. Now an overnflated bag is a different story. Think of a regular bic pen. Put the point down and press hard on the other end with your thumb. Notice how much in any position other than perfectly vertical it wants to jump out in an unpredictable manner. Same principal with an overdone bag.
If it's properly inflated, then it is in essence, lessening the load on the spring. Your truck will still sag some. But your 3" will likely become 1-1.5". Vehicle sway should not ever be an issue in your application. If it is, something very wrong.
One of the simplest airbag setups I have ever seen had the two airlines run to the fuel cap door. He used a bicycle pump to adjust them. If I remember right, 5psi unloaded for ride improvement and 10 psi for his camper.
Electric pumps and can gauges are nice. I would not try to sell you them because you know you load. It's the same load. After some trial and error, your gonna know what you like.

 

I have never had a sway problem with bags unless they were too hard. I have noticed that some trailers were worse. For example, 40' gooseneck deckover with a heavy tractor. I'd have to really add some air. Vs a 5th wheel that's 1/3 the weight. The camper was much harder to control sway due to wind.

 

OP is years old, but still relevant.

I'm on my second truck with air springs, and for my camper there is nothing better to me. I have separated fill (a must) and now only use a bicycle pump for simplicity / cost.

Ace has a very valid point however. At some point / load, air springs are not the answer and a spring solution is required, perhaps both in tandem maybe? I am probably right on the edge using 60 PSI in the air springs, but really happy with the results.

 

I fabed out some spacers like shown inbthis post, i used some stainless steel hardware with nylocks, did two holes per block, and look forward to getting a camper on the bed! forward side of rear overload
aft side of rear overload.

 

So stg, how did they work out for you after you loaded your truck camper?

 

Haven't loaded a camper in it yet, I've loaded heavy loads of feed and wood, so far it has shown to engage the overloads when weight is present. The driving with it loaded actually makes it very comfortable as opposed to no weight. This F250 has the 8ft bed and the camper package already present so with no weight the drive is harsh and splits your spleen... when I actually get a camper on it next spring i will show pics with and without the camper so the difference can be seen.

 

I'd suggest to the OP to get the HD spring set replacement and a new set of shocks. Carrying 3500 lbs on the bed and some of it on the tail is no small feat.

 

Wow! What makes you so against air bags? I am more than happy with them and the rancho 9000 adjustable shocks I purchased. Way more tunability for different loads than springs. Air them down for smooth ride when unloaded, 50 psi and pulls our 9k trailer like it’s not even back there. You can certainly throw a bunch of time and money at it with springs, overloads, etc but why???

 

You're right about carrying 3,500 lbs. ... it is no small feat and has to be done right starting from the tires up. My KYB shocks (no indication of what model#) work great and don't need replacing. I do not think they are the OEM shocks. I have the OEM camper package which adds the upper helper spring and the Sumo Spring's I added give me another 2,800 lbs. more carrying capacity to the rear suspension.

I could have gone with the heavier Sumo's which would have added 5,000 lbs. more capacity but after talking with the engineering techs at Super Springs International, they recommended the lower rated Sumo's. Now that I've used the 2,800 lbs, rated Sumos for a few years, I can say the techs were absolutely right. Replacing the entire spring pack was one of the options I looked at initially. Lots more money and I did not want a jarring ride all of the time due to a heavier spring pack always being in play. I just needed occasional help when carrying the truck camper.

In the end, I got exactly what I wanted to address my issue, the Sumo's do not not affect the truck's ride when no/light loaded and it actually was the most cost effective solution I looked at. 100% satisfaction.

 

We have the same setup and mine rides OK (like you'd expect a HD truck to ride) when no/light loaded because that upper helper spring is not engaged. Do you have additional mods that would explain why your ride is so jarring unloaded?

I agree that under load, with the upper helper spring engaged (and now with my Sumos), my truck rides and handles really well.

 

Well, i live in Iowa on gravel roads for one thing, and there is no comparison no matter how many "mods" one engages in that keeps the utility of the F250 but feels like a F150...Ive driven both, i love the ride of the F150 but require the capabilities of the F250...ive driven other F250's and they all drive like "Trucks" because thats what they are.. its no surprise... If you are almost exclusively driving pavement it might not bother you, but an F250 without a load is not like driving a sedan on the highway... not a complaint, just a statement.

 

You're 100% correct spud ... the kind of roads makes all the difference. 99% of our driving is on asphalt paved roads. The only time we go "off roading" is when we load the truck camper on and go camping at a provincial/national park or private campground with gravel roads.