Outer Limits 4x4 Board

has anyone got an airbag system that they can raise individual wheels while keeping there original suspension. i.e for side slopes.

p.s if your a wanker dont reply just click on another topic

tried searching?
http://www.outerlimits4x4.com/phpBB2/su ... hp#1423262 for example?

You wont get one where you keep your original shocks and springs... you replace springs with bags.

thats what i was sort of after (retaining the shocks and springs) i've seen comp trucks with hydralic rams that push on you springs and shocks but i was wondering if it could be done with air bags and what the mods would be?

matto wrote: p.s if your a wanker dont reply just click on another topic

good luck cobber

macca81 wrote:

matto wrote: p.s if your a wanker dont reply just click on another topic

good luck cobber

yeah i thought i would get in first

matto wrote:thats what i was sort of after (retaining the shocks and springs) i've seen comp trucks with hydralic rams that push on you springs and shocks but i was wondering if it could be done with air bags and what the mods would be?

Do it with airbags, but as bogged says, no springs after.

Airbags are to coils what coils are to leaves anyway. Better all round.

how come comp guys use coils or coil overs and not air bags, i thought air bags were used for towing because they dont compress as much

I imagine reliability would be an issue. An air bag could be easily punctured in competition use. also airbags have limited travel.

air bags are most commonly found on big trucks and trailers. because the actual load varies, you can soften or stiffen the truck/trailer suspension depending, thus reducing the damage impact to the road as well as offering a better ride.

also those wanker utes use them to make there gay utes drag on the bitumen and cause sparks

Yeah, the airbags adjust rates in relation to load.

I thought that they weren;t really used in comps becuase the rates ramped up with travel, where a a coil doesn't... but air shocks are failry popular. I guess this said, airshox are also usually set with ride height not much over max compression and the rest is drop travel, something thats probably not normally the case with a full bodied 4WD where there is usually a fair amount of jounce in the setup that comes with the additional lift.

oldmate wrote:also airbags have limited travel.

I am not sure where you get that info from.

The air springs on the GU have approx 390mm of travel.

Considering you can run them a 3" lift and match them with the right shock length they would travel very well. What 3" spring will give the same flexability and travel along with the load carrying capabilities?

Slunnie wrote:I thought that they weren;t really used in comps becuase the rates ramped up with travel

Not necessarily; a proper piston design can alleviate this. Effectively the shape of the piston in the air spring can tweak the spring rate depending on the height.

As for travel, not only is some pretty good travel available, how cool is an arrangement where you can have your 3" plus lift off-road, then drop down to standard ride height when you're driving home?

The significant downside is the risk of putting a stick through an air spring. But they are made of rugged rubber and so they can be about as tough as tyres can. And they are much easier to swap in a hurry than a coil usually is.

Having recently switched from coil springs to air springs (by swapping from a Mav to a Range Rover), so far I am loving the air suspension.

matto wrote:has anyone got an airbag system that they can raise individual wheels while keeping there original suspension. i.e for side slopes.

p.s if your a wanker dont reply just click on another topic

I'm a wanker - but will respond anyhow
Most vehicle airbags setup allow the vehicle to be lifted or lowered over the axle - but not suck up the wheel.
In terms of side slopes - in our testing dropping all the bags till you are on the bumpstops is better for side hills than it is to try leaning into them.

oldmate wrote:I imagine reliability would be an issue. An air bag could be easily punctured in competition use. also airbags have limited travel.

air bags are most commonly found on big trucks and trailers. because the actual load varies, you can soften or stiffen the truck/trailer suspension depending, thus reducing the damage impact to the road as well as offering a better ride.

Haven't had any reliability issues with my airbags and haven't punctured one yet - although I have seen damaged coils & leafs
Limited Travel - enough for my junk to do ok at westfeild:

But you are dead right about thevarying weight & ride.

sootygu wrote:

oldmate wrote:also airbags have limited travel.

I am not sure where you get that info from.

what i mean was compared so say air shocks & 4 links used in competition.

slunnie wrote:I guess this said, airshox are also usually set with ride height not much over max compression and the rest is drop travel

I suppose that could be achieved with airbags... anyone tried it?

Personally in the end i think the cost outweighs the benefits. But I'm cheap and would need a solid reason to lay big dollars down on a proper 4 corner air bag system.

depending on your vehicle setup....buy some air over coil-overs.
normal coil over with air bags on top.
have seen a few variations on this also.

but Mal's bushrangie runs them....must work ok, it's won tuff truck

This is what I think...

The reason why serious comp rigs dont run air bags as their primary suspension is because air bags arnt very good in full competition rigs. Its thats simple. The reason why they arnt any good is a bit more complicated but reliability and cost is not one of them. Its more to do with spring rate and suspension travel...imagine a coil that was so stiff as you try to compress it and a spring rate that is so soft as you try to extend it cobined with a spring rate that is really too soft at ride height with any respectable up travel then you are getting close to the sort of performance an air bag offers.

Air bags are great when setup up purposely tuned to run with very limited suspension movement. Things like 4wd that need to perform very well on road work well on air bags....so do big heavy trucks. An off road 4wd with lots of travel isnt a good place for them...thats why not many people use them...and that not for lack of trying or money or reliability...they just dont work that well.

Much better off spending coin on somehting that has been shown to work...linked suspension with normal coils and springs or coilovers or air shocks.

Sam

Some import pajeros come with airbags over the rear springs and on the torsion bar adjusters allowing for @ 2" of lift. The have their own air pump.

G'day Matto.

Airbags in my opion are great for a tourer. There reason that the "Crew Cav" ute has airbags is for an increased GVM of 1 ton. Making the ute a true 2 ton payload. To check out the airbags in action http://www.crewcav.webs.com There is a 4x4 section too.

"has anyone got an airbag system that they can raise individual wheels while keeping there original suspension. i.e for side slopes." I have found making the ute low as possible and perhaps putting more air to raise the down hill side may help. The air bag will not lift up the wheel on its own.

All the best, thanks Cav :-)

Strange Rover wrote:This is what I think...

The reason why serious comp rigs dont run air bags as their primary suspension is because air bags arnt very good in full competition rigs. Its thats simple. The reason why they arnt any good is a bit more complicated but reliability and cost is not one of them. Its more to do with spring rate and suspension travel...imagine a coil that was so stiff as you try to compress it and a spring rate that is so soft as you try to extend it cobined with a spring rate that is really too soft at ride height with any respectable up travel then you are getting close to the sort of performance an air bag offers.

Air bags are great when setup up purposely tuned to run with very limited suspension movement. Things like 4wd that need to perform very well on road work well on air bags....so do big heavy trucks. An off road 4wd with lots of travel isnt a good place for them...thats why not many people use them...and that not for lack of trying or money or reliability...they just dont work that well.

Much better off spending coin on somehting that has been shown to work...linked suspension with normal coils and springs or coilovers or air shocks.

Sam

I have long maintained that Airbags COULD be successfully used in a comp rig - but largely theis is not the case IMHo becuase:
1. Coilovers are easier and to certain extent cheaper to setup,
2. There are a range of different issues to address - as you suggest above - but they can be overcome.
3. Most bags offer a fairly small range of travel - unless they are very large in diameter which make mounting etc an issue.
4. Perception. eg that bags will be easily holed......

Wooders wrote:Haven't had any reliability issues with my airbags and haven't punctured one yet - although I have seen damaged coils & leafs

... and the peripheral gear????

Slunnie wrote:

Wooders wrote:Haven't had any reliability issues with my airbags and haven't punctured one yet - although I have seen damaged coils & leafs

... and the peripheral gear????

Snagged a poorly routed airline once - snip to clean it up and into a QuickConnect .....all of 2 minutes to fix....as I said generrally just misunderstood

matto wrote: i.e for side slopes.

Can someone explain to me why this would be good

All i keep thinking is if your cab is sitting level on a side slope you have nothing to scare the crap out of you and stop you finding the rollover point

PS - Hope that is not considered a wanker post

i do agree that your center of gravity point is not the roof but i would think that leveling it out would improve the roll over characteristics it also could stop you slraping the sides on banks or trees

matto wrote:i do agree that your center of gravity point is not the roof but i would think that leveling it out would improve the roll over characteristics it also could stop you slraping the sides on banks or trees

push a bit harder, your nearly off the bank..... honest

I didn't think we were talking about comp rigs necessarily. I will take Strangerover's word for it that in the end, at the extreme end of the spectrum, coils are better off-road.

But there's a lot to be said for air springs on a vehicle that is on-road as well as off-road. If you're still in the range of vehicles that are up to (pulling this out of my arse) 5" lift or so, air bags can do anything coils can do AND they can do a few things coils can't do, like squat right down when you want to or lower the vehicle to a safe height for road driving.

... on the other point, I agree I am struggling to see why it would be all that useful to be able to air up one side or the other side when you're on a side slope. It sounds good in theory but in real world driving I think it would be pointless (or worse).

What I think could conceivably be handy would be pumping one spring up so that you can get more traction on one particular tyre. But you'd want to get it back to normal again as soon as you'd moved on a bit.

At the risk of digging up an old joke, I think Bentzook had some good ideas for what a decent air suspension might be able to achieve - I think it was the layers bit which really brought him undone.

I like the concept that cross-linked bags force one air from one bag to the other - as one bag compresses, the other extends. This should (help to) reduce the increasing spring rate under compression. I suspect an external air reservoir could also help to minimise the change in pressure in the bag.

But this cross-linked concept is bad on a side slope - as the body rolls to the low side, and that spring compresses, the opposite side extends, increasing the body roll. There are probably dozens of ways to counter this.

It may depend on how the crosslinking is done. I was under the impression that the system used in the current crop of LandRovers was meant to be quite good in preventing body roll but assisting articulation.

try the rover post. I believe some of the Au military 110's had what you are looking for. I read a review many years ago about british mod trying out our system. I believe that it was developed by a suspension mob at rockdale area nsw. done with hydrolic rams. was expensive lol

I ran bags front and rear in my Pro Comp GU for 2 years in OBC. 1st year was no good - front bags were too long. You cant have stiffness, long travel and low ride height all in one. When I wanted to be driving flat out I needed stiff bags in the front and that meant bloody 8" lifted ride height with virtually no down travel. But rear was good. Following year we went short bags and much much better but we lost wheel travel in doing so.

Rear bags are good and long ones at that. Tyres tend to spend more time touching the ground than with coils or even coil overs and that means more drive. No punctures.

Dont kid yourself that bags can re-align on side slopes, etc. Yes they can but they can also mess you up. If the bags are passing air between themselves for added articulation it's real bad on side slopes as the car will lean further making it worse. Then you need to control bags independantly which we do too but your reflexes have to be lightning fast to hit the right switch in the right direction while also stearing and managing gear shifts and lockers too. I vote you forget the idea.

[quote="-Scott-"]At the risk of digging up an old joke, I think Bentzook had some good ideas for what a decent air suspension might be able to achieve - I think it was the layers bit which really brought him undone.


Using the airbag setup I initially had was going to lead past the last layer of Gravity, so now I think my latest plan my keep me on the edge for a little bit longer. Now I`m running Glen Dobbin`s coilovers in each corner on the outside of the chassis and think about mounting each airbag on the inside of the chassis. I can maintain sway control with the coilovers locked down and for slow movement 4x4ing , I could individually inflate/deflate the bags as needed and at full droop air release the coilover to use maximum stroke of the shock assisted by the bag.

Its all up in the air ATM but I think it could be done, and reach those outer layers of Gravity.