F-650 4x4 - OK with air suspension?


Hi Guys,

Some of you may have been following our designs for our Round-the-World vehicle based on the F-650 chassis.

We're now in the final stages of buying the chassis to start the build-up and have hit a hitch and I need experienced opinions...

Due to the ULSD Diesel challenges (see the other thread in HD forum) we've decided to buy a slightly used 2006 / 2007 F-650 chassis with the older CAT C7 engine.

We've just found a 'perfect fit' candidate, except that it has the AirBag Suspension, instead of the Leaf Springs that we had always been planning on.

We will be converting this crew-cab truck to a full 4x4 with A/T tires, winches, etc. It will be going around the world and seeing a lot of off-road duty.

SO, the question is:
  • How much worse / better is air suspension going to be?
  • Should this be a deal-breaker for this chassis? (i.e. - find another one)
  • How much articulation / robustness can you get from airbag?
  • Is the system too complex / risky to take around the world vs. leaf springs?
One person told me that you just carry a spare airbag, and replacing a bag is a lot easier than trying to build/replace a leaf spring.

Any opinions? Thanks!

(Duplicate Post in the HD Forum - Not sure where this one should go)


Most of the Logging trucks around here run airbag suspensions. Those trucks come out of some rough roads and overloaded if they can get away with it. - Brad


16 Years on ExPo. Whoa!!
In my opinion, if you want a better ride, then remove a lead or two so it flexes better and use air bags but it is a lot to rely on to just have air bags.. Also, bring plenty of spare parts, even possibly a whole second kit in storage, fittings and lines, spare bag, etc... It will probably ride a little softer but a semi-mixed bag. I'd say 98% of air bag applications stateside at least are done for overload purposes only...

Suspension wise: compression up, slightly reduced depending on air pressure. Down, as much droop as you'd like also dependent on set up. Also -- to run just air bags you'd have to construct a linked rear suspension. A lot of work. Again I would leave and use as overloads only, or remove a leaf or two to greater rely on the air bag and still get more pleasurable suspension riding..

EDIT sorry didn't read entire first post... If designed that way then probably an advantage. But again carry spares...
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This truck already has an airbag suspension. So it is probably already set up with a linked suspension. It probably is as heavy as the large trucks if it is on a F650. It should have on board air and can be made adjustable from the cab. I think the air ride system will be more comfortable and adjustable than a spring system, but leaf springs are pretty well bullet proof. So I think more reliable but to what degree?

The air assist system on my truck is great for the ride because of the on/off loading of the camper, but I do have a slow leak that I cannot locate on one side.


Expedition Poseur
There are so many air ride trucks on the road now that I think that air ride systems have proven themselves as viable options. The big question is has the system on the chassis you are considering proved itself. If I were in your position, I would talk to people who are using that particular system. Find the fleet manager of companies running that system, buy him a beer and talk about his experience with them...good, bad, or otherwise. I would definately rebuild the system before leaving (replace all the air lines, fittings, etc., this will ensure you have the right spares and the experience to repair the system if needed), and carry plenty of spare parts. Stock up on the hard to find little stuff---compression fittings, etc.

If it really bothers you, you can always have the air ride system ripped off and retrofit leaf springs onto it. But personally, I would be looking for a air ride truck anyway....

Ron B

I bagged my hummer a few months ago -- I know my truck is a bit different because it's all independent suspension, but the ride is really smooth on and off the road. The bags themselves are easy to replace if there's a problem (they are supposedly nearly as thick as a tire sidewall). The systems can easily be set up to fill the tank from an outside source if there's a compressor failure. I am pretty new to this so I am still learning, but so far the variable height/smoother ride is pretty cool.

Here's a link to a pretty nice set up for hd trucks...maybe it's similar to the one on your truck?



Grim Reaper

Expedition Leader
Carry a spare bag and some lines and you should be fine if you are not planning any huge suspension mods. A 2-4 inch suspension lift may be as simple as a few extra pounds in the bags or a spacer on the bag mount.

Ride always improves when you remove unsprung weight. You lost a LOT of weight when the springs came off. So thats a plus.

Honestly as long as you have the tools to lift the truck and carry the spares I think you can easily handle any problems you have with the bags AND have a better ride then you could ever get with leaf springs.


I have driven and been around semi trucks and medium duty trucks all of my life (40) and I have never seen an air bag on one of these trucks fail. I also ran an air ride suspension on my dodge for a few years with no bag failure, but one line failure due to operator error. I have only heard of one guy say that he lost a bag and it was on a trailer. Maybe if it was punctured by something on a trail you could see a failure but as big as your rig will be you are not going to see tight wooded trails. I had a 2004 International 4300 with air ride and the ride was excellent. I used it to pull a 34ft. gooseneck trailer. Before it I had a 1998 GMC Topkick with spring suspension, this truck was miserably rough riding pulling the same trailer. Almost every (not saying all) semi tractor you see on the interstate in equipped with air ride suspension. It is even becoming popular on the steer axle. I would carry some spare air line these fail once in a while mainly due to chaffing. You can get air line and push-lock connectors at NAPA. The push-lock connectors are great, all you need to repair a line is a knife.


Thanks for the advice

Hi All,

That's why this is the best forum on the 'net...

Thanks very much for your rapid and detailed advice. I'm going to look into your various suggestions, but I feel much more confident about the decision now.

Just to clarify on a couple of the comments:

- It is a F-650 (2007) not the older series F-700/F-600

- The rear suspension is air-only, not air + springs

- The front is still leaf springs, but someone has suggested changing that to a 4-link air-only setup as well...

I'll send you all pics on this thread if the deal goes through.

Cheers & thanks very much.


Colorado Ron

Nothing wrong with air bag suspension. Most of the guys in Iceland run airbags.

Heres my good friend Thrandur in Iceland with Sport Trac I sold him after he converted it to airbags. With adjustable ride height he can raise in when crossing rivers:


And if thats not enough, I believe this one has airbags in the rear and made it to the South Pole:


Ron B

I'm loving the bags as well. As I mentioned a few weeks ago, they really smooth out the trails and gives me some great ground clearance when it's needed.

here's a shot of my truck at close to full inflation


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