[shep]

Can airbags be used just to help with load capacity but when unloaded not affect the travel of the springs?

[joel]

yep, dont fill them with air when not needed and it will be like they arent there.
a mob do a helper spring that you can turn on when needed and is a soft old mans willy when not in use.
think tjm may stock it, and various other 4wd mobs.
can also just get a normal setup and run an overflow valve on it, so when the leaf flexes and puts pressure back into the air bag, the airbag deflates via the valve and allows the leafs to act and flex as normal, but be warned, it was taxing on the compressor when we installed it, as the pressure is always fluctuating in the airbag and compressor tries to maintain a constant.

one way we overcame it was to have a regulator mounted in the cab, just for the airbags, that way you could tun it down and only slightly fill the bag, that way when the leaf flexed, and the bag exhausted excess pressure out of the valve, the compressor had to work less to fill the bag again.

[shep]

Sorry joel but having to run a compressor to keep topping up a bag sounds silly.

Does the airbag need to be attached to both the chassis and the spring? At full droop I get a bit over 500mm between the diff an the bumpstop but only want around 150-200mm when loaded.

[joel]

its not to much of a hassle, as you can control the level of air in the spring, and the amount of air released (if any) via the valve. you would only need to do this when completely unloaded and still wanting some epic flex.
or personally i would just run a normal air bag and just carry some weight,
but either way you compressor will always be feeding the air bag one way or another, unless you want to hop out and pump it with a football pump every time.

next time your up old man, i will show you the vehicle its on, its incredible.
best bet is to mount it to the leaf and the chassis, but mount to the chassis via a wide load bearing plate that will absorb, or at least spread the load along the chassis and not isolate it to a small surface area or you may have some chassis cracking damage (isnt that right mr telstra patrols)
the mobs will have an airbag that will suit your measurements and load carrying needs, also i recommend running the compressor to an air tank, say a 25 litre tank, that way the compressor wont do so much work in the above mentioned installation.
that was the fix for the vehicle and it made a huge difference, we suggested to do it that way from the get go, but the client didnt like the idea, he liked the compressor raping his ears even less, so we put the tank in.

[laurie]

yes
i had polyair bags in the rear of a previous car
2wd wagon
attached to the top only inside the coil put air in when towing or loaded
let air out when not and forget they are there

leafs i do not know but that was a while ago

[shep]

I don't want to overcomplcate something that doesn't need to be complaced. If a air bag doesn't need to be attached in two places then I will never need to change the pressure in the bag. Why carry all that other stuff if it isn't needed.

Laurie. I want to stick the bags on a leaf sprung car so no coil to locate the bag

[joel]

how much weight you looking at carrying??
you cant fit that much in there, (weight wise) both legally and practically. i think the better idea would be to put the money into the trailer build, that way you kill 2 birds with one stone, much easier to tow a trailer loaded to the hilt correctly than stuff it in the back of the zook over the back axle.
just keep the back for the fridge and delicate stuff, like zip tied gaffer taped foreign hitch hiking back packers.

[laurie]

http://www.airbagworld.com.au/polyair-s ... nsion.html

[joel]

god damn my naughty corner delayed post.

[ajsr]

shep
after looking at vehicle chassis for many years I have an opinon that air bags are not a great idea on a lot of leaf sprung vehicles and there many pics of utes ect with bent chassis to prove my point. they concetrate too much load in places the chassis was never designed to have it.
so go easy with the loading
coil spung chassis are a different thing.

[joel]

ajsr wrote:

shep
after looking at vehicle chassis for many years I have an opinon that air bags are not a great idea on a lot of leaf sprung vehicles and there many pics of utes ect with bent chassis to prove my point. they concetrate too much load in places the chassis was never designed to have it.
so go easy with the loading
coil spung chassis are a different thing.

truth gwagon in that, telstra have stopped all airbags and are currently having them removed from there vehicles.

[shep]

Ajsr I am talking about a 300kg payload and using bags to support 100 kg of that load. my springs work great until ya stick 100kg of fuel and 50kg towbar load on it.

[ajsr]

well they should work great then at about 5-7 psi

[got_bar_work]

Wat shocks do u run
U might be better off with airshocks
I dont think u could run the bags attached a one end only
They would flap around

[SierraDan]

Id imagine the types of roads shep drives on at speed might generate too much heat and make the air shocks useless and/or blow seals.

[dank]

ajsr wrote:

shep
after looking at vehicle chassis for many years I have an opinon that air bags are not a great idea on a lot of leaf sprung vehicles and there many pics of utes ect with bent chassis to prove my point. they concetrate too much load in places the chassis was never designed to have it.
so go easy with the loading
coil spung chassis are a different thing.

THis is only because people don't understand how to use them or are asking too much of their vehicle. like, if you are tryign to carry 2 tonne of wood in the back of your hilux plus two a tandem horse float and you have the original springs in there and you put 200psi in the bags to compensate for the load then of course the chassis will be fucked.

i've been selling airbags for 5 years and not had one customer that i know of ever damage their chassis.

shep I have a triple bellow bag that might work, still wont get to 500mm extended though.

[shep]

Do they need to be attached to both the chassis and the diff? or can they pop apart like a coil spring that isn't anchored both ends

[Zook_Fan]

500mm is almost 20inches of travel? How long are the shocks in that thing?

[shep]

Extended is 980mm

[dank]

shep wrote:

Do they need to be attached to both the chassis and the diff? or can they pop apart like a coil spring that isn't anchored both ends

Technically they do need to be attached at both ends but you could potentially mod the kit which would allow the airbag to be released off the chassis you would just need a way of making sure that on compression the bag will again be sitting back on the chassis rail.

[got_bar_work]

Add a air ram like a twin shock set up
Use it the same as u would the bags but have the travel u need