Do air bags cause D40 chasis to bend ??

I was just talking to a suspension guy and when i told him that i wanted a 2 inch lift and air bags in the back for towing a 21 foot van (when i get it ) he told me that i cant put them in a D22 or a D40 .Has anyone heard this before or is it one of those things that happened under an extreme case . Im also looking at getting a dobinson 2 inch lift are these a good set up ???

Airbags will cause problems with an overloaded vehicle, for sure.

The problem with the airbags stems from where they are located. The area of the chassis around the leaf spring mounts is reinforced and designed to take the maximum weight of the vehicle even on rugged terrain. The area of the chassis where the airbags make contact is not reinforced.

The incidents we've seen (not just in the Navara community) with broken chassis all relate to overloading. If you're going to do things right you probably don't have a worry at all.

For me, I have the choice between airbags and triple action springs. I'm going to get the springs - because I don't want to risk the chassis at all, even if the Firestone air bags come with a larger plate spreading the airbag contact across a larger portion of the chassis.

It's an extreme that causes the failure. You could probably safely use the airbags as long as you use them per the manual - no overloading, reduce pressure with a reduced load etc etc.

Airbags do compromise your suspension travel for off-roading as well (flex is reduced). This may cause other issues - but if you don't go off-road a lot, that won't be a big deal.

Treated well I don't think the air bags would be a huge drama, but personally I won't go that way.

As for lifts - I can't help yet, I'm not putting a lift in mine. I am torn between Bilstein shocks and OME Nitrocharger Sports - still undecided which way to go with those. Dobinson shocks were (according to the salesperson) not as good as Bilsteins (but better than Tough Dog). I am unsure how much of that advice is retail margin influenced!

I was going to go bilsteins but apparently they dont do shocks for lifts but if you are staying standard height they are as good as it gets . Ive had them in 4 vehicles 2 cars and 2 4bys ,Ive had bad experiences with old man emu but that was a long time ago crossing the simpson . Does any one no if Koni do a 2 inch lift shock thats adjustable .

What size van do you tow tony ?

It's a 1.8T 18' with a long drawbar, 7.5M in total. Have a couple more pics in the garage, but this one's a fav:

Chrome dome said:

I was going to go bilsteins but apparently they dont do shocks for lifts but if you are staying standard height they are as good as it gets . Ive had them in 4 vehicles 2 cars and 2 4bys ,Ive had bad experiences with old man emu but that was a long time ago crossing the simpson . Does any one no if Koni do a 2 inch lift shock thats adjustable .

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considered toughdogs? bit more $$ but worth it

I am considering tough dog and ultimate suspension but the only problem with ultimate is getting my car there for the day .

Hey Chrome dome give these a go i have been thinking about them but need a test dummy first LOL.
http://www.raiz-a-bac.com.au/
They look and sound alright i got a price a while back they where around $550 i think so somewhere in between the cheap and the expensive airbags.

my navara has air bags in the back .. there where already in there when i bought it when i get my 2''lift im getting rid of them ...

It appears quite a few things may cause chassis problems on various makes. A few possibilities in this one. An oldie but a goodie:

http://www.4wdaction.com.au/forum/viewtopic.php?t=99859

joe2006 said:

It appears quite a few things may cause chassis problems on various makes. A few possibilities in this one. An oldie but a goodie:

http://www.4wdaction.com.au/forum/viewtopic.php?t=99859

Click to expand...

I feel bad for that guy and your right mate, they just don't make them like they use to...

Hey longy wouldnt those raiz a back springs still have the same problem as the air bags . Putting more stress in a weak point .

its not about wither the chassi is reinforced or not. the problem with airbags is its very easy to pump them up and they take the weight off the main loading points and onto a single point.

this gets worse if the stock springs sag and more and more weight gets transferred through the bags.

rough roads and poor shocks compound it further.

Yes, but if that single point is reinforced you are less likely to have problems.

they are not reinforced or designed for that loading.
wither you get away with it or not is down to how its designed in the first place. if its over engineered it will be fine. not many companies waste money making things stronger than it needs to be.

Chrome dome said:

Hey longy wouldnt those raiz a back springs still have the same problem as the air bags . Putting more stress in a weak point .

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I'm not sure mate, but i would say the coil spring would always have a bit of give in it where the airbags on the other hand if they get pumped up to much for the load they would have no give.
That's just my theory though.

good point. i don't know how much travel you get with the bags pumped up.

just to add to previous posts.... the utes with chassis cracked/buckled in front of the rear springs is not an airbag issue. thats simply an overloading issue which would happen no matter what spring system you run.
chassis cracks/bends in between the springs is more of a airbag issue.

Hi all
I've had air bags (with standard suspension) for about 12 months now and had no problems. I have gone thru Victorias Big Desert region last november and it was a big help as i could not afford a complete suspension lift. But, as of Tuesday next week , up she goes with 2" tough dog all round, medium springs at the back as i am empty most of the time. Damn, i should be loaded and off checking out some of our great camping areas more often.
I'll try to get some before and after photos for everyone.

Stole these photos from another forum. Obviously not a Nissan one but the ute could be made by any manufacturer.