Let's talk air bags...

[adamis]

My 1999 7.3 dually has airbags installed by the previous owner. I've generally not bothered to inflate them unless towing a trailer with my Bigfoot camper (4000lbs loaded). Today while driving on California's 101 near San Jose I was bouncing along from our overtaxed and under fixed roads.

While bouncing up and down I had an epiphany that perhaps a little bit of air might help the situation. Typically I've run between 30 to 60 psi in the bags if I'm towing a trailer with the camper. If I have just the camper I have usually left them empty or at 30psi unless I'm on twisty roads where I might bump it up to 90psi. That being said, it seems app subjective to me. Hard to tell if adding air I'm helped at all or if it was just the roar improving in the section I was then on.

So those of you that also have airbags, what type of truck and camper weight do you have and what PSI in the bags do you run? What is your measurement of ride improvement other then subjective "feels better"?

[2Z_Bundok]

JimK-NY wrote:
Timbrens should not "suck" if the truck is empty. If properly set up they would not be engaged if the truck is not loaded. Also you need to select the Timbren based on the maximum load. If you carry a truck camper, you will need a "severe service" Timbren. There is a standard Timbren built for lighter loads.

That is my understanding so we got the "SES" severe service.

[towpro]

I can't say enough great things about the Torklift Lower Overloads on my Ram with leaf springs. And the best part is you can disengage them when driving with camper unloaded. Plus they now make them in stainless steel.
If I was to do it over, this would be my first change.

[JimK-NY]

Timbrens should not "suck" if the truck is empty. If properly set up they would not be engaged if the truck is not loaded. Also you need to select the Timbren based on the maximum load. If you carry a truck camper, you will need a "severe service" Timbren. There is a standard Timbren built for lighter loads.

[Grit_dog]

Supercharged111 wrote:
I had Timbrens on my 1500 back when it was stock and they sucked empty. I had very little travel before engaging them and when you did your spring rate seemed like it hit infinity.

Better suited for heavy loads than lighter loads for sure. They are somewhat height adjustable so you can balance when they engage with how much sag you're willing to accept.

Wouldn't recommend them for "a little" support and if only used occasionally, keep them short so you get enough travel for empty truck bed under normal road conditions and they only engage under a decent load.

I ran 'em for years on a few different half tons. But they were work trucks that the company felt I only needed a 1/2 ton.
After a 90 gal slip tank and hundreds of lbs of tools in the bed all the time, you almost couldn't haul a trailer with any real tongue weight, without some extra rear suspension. Mine basically rode on the Timbrens 24/7.

No, I didn't care about payload rating. Would also run the first set of P or XL tires up to 60-65psi in the rear to get the squish out of the tires.
FWIW, a 44psi max rated tire will run all day long at 60psi with more weight in the bed than should be there, without issue!

[Supercharged111]

I had Timbrens on my 1500 back when it was stock and they sucked empty. I had very little travel before engaging them and when you did your spring rate seemed like it hit infinity.

[Grit_dog]

2Z Bundok wrote:
We just got a set of Timbren to try this spring. I like the reports from years of users experience / no maintenance and lifetime warranty. About the same price as air bags.

2Z Bundok
94 GMC k2500 6.5TD
97 Shadow Cruiser

Timbrens are a great, no hassle, economical, easy to install option.
Never used them with a TC specifically, but have on other trucks and IMO, they will work great on a TC. I thought about ditching the bags on the old truck for them, as I'm pretty sure they will do more to control body roll than bags, while doing a good job at holding the load as well.

[2Z_Bundok]

We just got a set of Timbren to try this spring. I like the reports from years of users experience / no maintenance and lifetime warranty. About the same price as air bags.

2Z Bundok
94 GMC k2500 6.5TD
97 Shadow Cruiser

[adamis]

One thing I have taken for granted is having on onboard air system so I can change the air pressure of the bags from inside the cab with the flip of a switch. I think it is a must for any airbag installation to be practical. Being able to change on the fly due to changing road conditions is what makes airbags useful.

Perhaps the different experiences with airbags is due to why they were installed in the first place. Some here might be in the camp that they have way more camper then their truck can comfortably handle and require the airbags to "level" out the truck and assist the suspension.

Others (and I think I am in this boat) have just enough or more then enough truck for the camper and don't require the airbags to level the ride height (I have fairly minimal sag with camper) and just use the airbags to improve the ride in varying conditions (higher pressures for winding roads, lower pressures for bumpy roads).

Perhaps that is why there have been such different experiences?

[JimK-NY]

I had simple Firestone airbags that were not connected. The bags sat on the top of the axle and were compressed from above by the frame.

The RV dealer did the initial install and set them to about 50#. I had to drop the pressure way down to suppress some of the sway. Later I stopped at the Northstar RV factory and the owner took a look at them. He set the left side to about 45# and the right side to about 50# claiming that a little slant was best for highway driving due to the crown of the highway. A drive across the parking lot was clear enough and I again dropped the pressure to about 10-15#. I cannot say the ride got stiffer at high pressures. Instead it was more like driving a vehicle with no shocks even though my Ranchos were max'd out.

Anyway, the issues were resolved. My old truck did well with the Supersprings and my new truck does well with the Timbrens.

[HMS_Beagle]

There are two common ways airbag helper springs are installed: on top of the leaf springs connecting to brackets hanging out from the frame, or on top of the axle directly underneath the frame rail. The former will maintain the roll resistance (and even increase it if the effective spring rate goes up), while the latter will reduce the roll resistance to the extent they are carrying any weight. That could partially explain why people's experience differs.

[Supercharged111]

JimK-NY wrote:

Avid Fox wrote:
I had airbags on my old 2005 F250 4x4 and Lance 845 combo. This was the suggestion of the dealer I bought the camper from.

I found them to work fine for leveling up, however it was also like riding on top of a squirrelly beach ball, and adding a huge rear sway bar and rancho adj shocks didn't help. It simply unloaded all the metal springs and carried the weight on the airbags. Great for a trailer tow but horrible for a camper.

No more airbags for me.

Yup, "riding on top of a squirrelly beach ball." That matches my experience with airbags.

Did you inflate both bags independently or together? When I add air, my truck gets stiffer.

[JimK-NY]

I have no idea why we see such different results with airbags. The dealer put mine in the 50# range. They did a great job of leveling the suspension but the sway was horrible. I tried different pressure and found that low pressures in the 15# range helped somewhat with level. The ride was better but still bad. I had to bump up the Rancho shocks to the highest settings and then had a very harsh ride. Tar strips on the roads hit hard. I drove for a couple of years and then got Supersprings and dumped the bags. The ride was greatly improved with little sway and I was able to lower the shock settings to a medium level.

I had a 4000# camper on the back of a 2500 Ram so about 7500# on the rear axle. Now I have a 3500 Ram. I added Timbrens to help level the suspension. The ride is a bit soft but I don't see the need for Supersprings.

[adamis]

I have to agree with Grit Dog, never experienced that effect, in fact, quite the opposite. If I am on a twisty mountain road I will inflate the airbags higher then usual to help eliminate body roll in the curves. Does wonders in that situation.

I am wondering if you just over inflated the air bags such that they unload the rear leaf springs entirely. That would have the effect you are describing I think.

Airbags are designed to assist the suspension, not replace it.

[Grit_dog]

There’s a balance between too much and not enough air.
If you were riding a beach ball, you didn’t figure that out or you had way too much camper for the truck.