As a contractor who carries a constant load of 300 - 400 pounds (added to my liner/canopy weight/cargo-bed of 450 pounds = total 800 - 900 pounds), I have always found that my F150 rear springs start to sag after about 6 - 8 months. Because of this, it's my standard practice to have a spring shop install an extra leaf in the rear.

This has worked well. Although when running empty the ride has been a bit harsh.

I have not yet re-sprung my new truck, as I'm considering alternatives and would like suggestions from those who might have experience.

Right now I have only a plywood box-liner and heavy duty canopy installed and this has already lowered the rear of my 2011 XLT 4x4 enough that if you looked at my truck you would think I have a levelling kit installed. (I have not yet loaded up with my 300 - 400 pounds of equipment.) With my current load of 400+/- pounds, my truck rides like a limo... very smooth.

I'm wondering whether I'm best off following my usual practice of an extra leaf which has worked well. (about $500 installed) Or if I should be looking at Supersprings or something like these: http://www.suspensionconnection.com/...r-springs.html I know air bags are an alternative, but I think they're more expensive and might be a hassle.

I'd like to keep the ride decent, but most important keep the rear from sagging.

 

If it were me I would go with airbags, you keep the good ride when unloaded, but when you load up you air up to keep the rear end from sagging

 

That's a fair solution, and I'll ask them for an estimate, but unless I get a built-in compressor as part of the package, it might be quite a hassle to adjust the air, no?

 

I installed firestone ride ride rite bags on my 2011 SC they are way to much lift for a 900 lb load you must maintain at least 5psi in them at all times. I did not have the on board air and yes it was a hassel to maintain proper pressure I took them off and sold the on Craigs list for1/2 what I paid for them. Go with add a leafe Bubbabud XLT SC ecoboost

 

I just installed Firestone airbags, firestone auto levelers, and viair onboard compressors system (2 compressors and tank). Above parts, misc fittings wiring about $1000. I did all labor but took solid weekend.

Auto levelers are great, you don't touch the air bags they are automatically filled by tank.

You can buy a cheaper oba system then I did.
I'd Recommed the above route. If u want more info let me know or shoot me a pm

 

Without onboard air it is more of a pain, but you just have the valve stems come out by the back bumper and air them up when needed....if it's not something your adjusting on a daily basis it's not bad

 

If you carrying the amount of weight daily and Different materials often I'd install the auto levelers. That way the bags are also adjusted properly and u don't have to worry about them

 

Supersprings, once installed will never have to deal with them. I added them with a level kit and bigger tires so I don't have a direct comparison from stock with just the springs, but overall the ride is very slightly stiffer (I think mainly from the level and supersprings) and the bigger tires likely take some of the stiffness out of the system.

Unloaded, truck basically rides like they were not installed, except for the noticeable difference while cornering. I get noticeably less body roll.

Loaded, well, they work as advertised, a 600 lb. load in my truck two weeks ago and my rear only dropped 2". Without it, my rear would drop almost 4" w/ ~250 lbs.

I really looked at the air bags and would have gone that way, but I would want the onboard compressor and auto level system. Cost and effort of install was more than I wanted to do. The Supersprings take about 2 hours to install them if taking your time. Though I sometimes wish I had an onboard air system for uses other than air bags.

You also mention long term - the spring setup would definitely get the nod. There was another system that I can't recall where I've seen it, but it was a spring setup between the frame and axle where the bumpstops go. Sounded like a plausible solution maybe worth checking out also.

 

At $200, airbags are a good alternative if you have an air compressor readily available at the house. I mounted my valve stems next to the license plate on my old truck and never thought it was a pain of hassle

 

I forgot about those! Timbren, if I remember correctly.
Had a pair on my old 88 GM 3500. They were basically a big rubber shock. Didn't work too badly but needed alot of weight on before they came into play.