What do you guys know about airbag springs?

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rokhound
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What do you guys know about airbag springs?

Post by rokhound »

I am rebuilding the 'mutt into a road legal rig which involves a new chassis and suspension setup.
It is going 4 link in the rear (instead of the current A frame) and 3 link in the front, (instead of the current 5 link).
What I want to know is if air bags will help me control the spring rates, or should i ditch the springs and go air bag all the way. At the moment the truck is in no way streetable due to the very soft spring rates that get it articulating really well over the terrain I drive on. It would be nice to be able to have this set up when crawling, and then adjust all the spring rates for street driving. Open to other options as well, including hydraulic etc ( as forced artic would be real handy as well).
If any one can comment here, or direct me to useful sites elsewhere, it would be much appreciated. :P
Last edited by rokhound on Sun Apr 27, 2008 6:47 pm, edited 1 time in total.
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turoa
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Re: What do you guys know about airbags?

Post by turoa »

I dont think you can control the spring rates with airbags without lifting it up or down. down = softer. high = harder. Unfortunately its the wrong way around. Still, airbags all the way
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swampa
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Re: What do you guys know about airbags?

Post by swampa »

get a good set of coilovers
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Re: What do you guys know about airbags?

Post by Steve_t647 »

I cant help but chat to these boy's http://www.thedropshop.co.nz/ they are in Auckland but I have driven 2 of their customers hilux's (2wd) and they got them right.

Are you thinking of using the airbags to replace the spring rate or as a damper to help control and stiffen it. Be interested to see how you get on keep us informed.

Also you could use the airbags (if large enough) to level the toy offroad
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rokhound
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Re: What do you guys know about airbag springs?

Post by rokhound »

Just playing with ideas at the moment Steve :D
I really like being able to lift a wheel 1200mm, but I would also like to be able to drive it on the road every now and then. I am starting a whole new set up some time soon, and want to make it road legal, so any thing i do has to be certifiable ( a bit like me :P ).
Front coil overs are looking good the moment, but at $1200 a pair, a little pricey.
Fox nitro shocks are also looking good, but they are apparently finicky with temperature changes, and I don't like that the main shaft (no smart arse comments) is exposed to all the bullshit, or the high pressure nitrogen that you need to adjust them.
The idea of airbags mounted on the control arms makes a lot of sense as well. This would give me the ultimate adjustably, including forced artic. I just haven't been able to find any where that can give the info on this set up that I want. I want to know what sort of vertical travel I can get out of the bags, If they are pliable and strong enough for rock work, If, by doubling up bags I can vary spring rates etc.
I am trying to get a rig that gives nothing away to what mine does now, but can be driven on the road with reasonable manners.
That should be easy shouldn't it :?: :wink: :wink: :roll: :roll: :lol: :lol:
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Steve_t647
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Re: What do you guys know about airbag springs?

Post by Steve_t647 »

Thinking left field here could you not use your winch to pull the body down and remove a adjustable air shock? the shock made removeable with pins and only used onroad to reduce the spring action and stiffen the ride? meand an extra 4 shocks i for each corner but when removed you have exactly what you want.

http://autospeed.com/cms/A_108592/article.html

I think you will have to control the arm's with the bags, the above link is some serious reading and some maths for you :lol:

Edit: Bugger I remembered what the paint on the van reminded me of, hope that is no indication :twisted:
I think you can get airbags to do what you want tho, are you going engine driven compressor or just find a pressure for the design and recharge from a tank?
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Re: What do you guys know about airbag springs?

Post by KiwiBacon »

It's damper and swaybar tuning that will make your truck drivable rather than vertical spring rates. Well valved dampers won't hurt your articulation offroad, swaybars will need disconnects to get maximum articulation.

Airbags have a shaped piston they sit on. The shape of this can determine the rate at different points throughout the stroke. Variations on cylinder shapes, cone shapes etc will change the rate of progression.
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Re: What do you guys know about airbag springs?

Post by De-Ranged »

:D air is the way of the future :lol: good to see your jumping on the band wagon

I'd tell ya how I'm doing mine but I don't think you'd be keen :lol: I'm at the silly stage now if I can get around to it :roll:

Anyway I was thinking about what you want the sway bar with disconects would be a good start, if you wanted a more adjustable option and one that would help out for forced articulation then another set of bags working under the upper links (they wouldn't need to be as big as they arn't supporting the body just lifting one wheel)
then build a valve bank from hell... this is the fun part 8)
for offroad cross link your back to front and opposite corners and the up and down bags and wollar you have forced articulation, change your valving so your applying preasure down on one side and up on the other and you level out the off camber stuff :wink: drop in's and climbs same deal just adjust forward and back
Now the good bit for road pump up your upper link bags to a high presure and keep the truck nice and low onroad and effectivly give it a way higher spring rate :D
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rokhound
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Re: What do you guys know about airbag springs?

Post by rokhound »

Now you are cooking Reece :P :P
Talking of silly ideas, I was looking at creating the coil over's with the adjustment retainer nut as a slider that is connected to a hydraulic ram. This would in turn adjust pressure on the spring pack, and create forced artic, but I am doubtful as to how useful this system would be for drive ability, as all it does is put more pressure on the springs (that you have already picked to be the right rate for their application)

Also remember reading about traction bars (when they were the thing in the 80's). The write up stated that all they effectively do is turn the axle housing into a giant sway bar. If this is the case, then why can't clever link design, with disconnecting joints in the all right places (for off road use) create exactly the same system?
I am ditching the current 4 link plus panhard set up i have in the front in favour of a 3 link plus panhard. If there are disconnect- able joints on the main control arms that mount up higher on the axle housing (essentially a Y shaped arm), then this should work, shouldn't it?
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Re: What do you guys know about airbag springs?

Post by De-Ranged »

rokhound wrote:Now you are cooking Reece :P :P

:lol: you have no idea how long I've spend thinking on this... that is the simplist system to achieve adjustable control

Talking of silly ideas, I was looking at creating the coil over's with the adjustment retainer nut as a slider that is connected to a hydraulic ram. This would in turn adjust pressure on the spring pack, and create forced artic, but I am doubtful as to how useful this system would be for drive ability, as all it does is put more pressure on the springs (that you have already picked to be the right rate for their application)

Your starting to think outside the sqaure :wink: now add dual action air rams (with accumulators) swing arms, all working on the coil over and you have a suspension system that tracks high speed whoopdee do's, jumps etc yet without any valving changes can give all the rock crawling performance :roll: well in theroy :lol: we'll have to wait till I've built it to see if the air rams can handle it

Also remember reading about traction bars (when they were the thing in the 80's). The write up stated that all they effectively do is turn the axle housing into a giant sway bar. If this is the case, then why can't clever link design, with disconnecting joints in the all right places (for off road use) create exactly the same system?

Yes it would but to work effectivly you would have to go to steel bushes or bearings at your pivot pionts this will lock the arms to the housing as one structure, this will mean alot of extra road noise and vibration also there is the issue of calculating what spring weight an axle tube assembly and linkages would be... :shock: a swaybar would be so much easyer in fact I'd suggest using two light ones clamped together with the end clamps being able to be adjusted in to soften them up or vice versa :wink:

I am ditching the current 4 link plus panhard set up i have in the front in favour of a 3 link plus panhard. If there are disconnect- able joints on the main control arms that mount up higher on the axle housing (essentially a Y shaped arm), then this should work, shouldn't it?

your current 4 link is the eqivelent of a three link for calculation perposes, (you still use the panhard to locat laterally ) so no real gain there, yours works well why not leave it there
what you would effectivly be doing with your Y design is turning the outer links into radius arms :wink: and I think you've driven a rangi before unless your willing to go the path of hard bushing it won't make enough difference to be worth the trouble, oh and I just thought of another thing :lol: the "window" of opertunity where the syspension would be sitting just right to bolt them up or unbolt them if they were hard bushed would make using them a bastard and a half :roll: I could just hear it now ... "bleed the right side .... bit more ... bit more ... bugger na still got a twist... try some out of the back .....pump up the :lol: " how goods your patience Rok :lol: I know I'd never use it
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swampa
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Re: What do you guys know about airbag springs?

Post by swampa »

what about what the aussie guys are using in the tuff trucks over there, massive hydraulic coilovers?
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rokhound
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Re: What do you guys know about airbag springs?

Post by rokhound »

swampa wrote:what about what the aussie guys are using in the tuff trucks over there, massive hydraulic coilovers?


Good point. Does any one have some close up/detailed info on these systems?
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turoa
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Re: What do you guys know about airbag springs?

Post by turoa »

those coilovers cost $7000au for 4, otherwsie id buy some.

im looking at airbags for my landrover, but probably just gonna run em with paddle valves, heaps easier to control and cheap
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swampa
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Re: What do you guys know about airbag springs?

Post by swampa »

say 8k, or 2k for each corner, not much more than a top coilover with 18 inches travel, 30inches of travel arent they? if you take into account the time and money to nut out a good air bag and the trial and error involved , in my opinion it is good economics, and they stick out the bonnet 12 inches
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Re: What do you guys know about airbag springs?

Post by kaney »

swampa wrote:and they stick out the bonnet 12 inches


on a roll over rig like roks wouldnt they get damaged (no offence intended)
toymota thats stock standard.
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Re: What do you guys know about airbag springs?

Post by H2OLOVA »

kaney wrote:
swampa wrote:and they stick out the bonnet 12 inches


on a roll over rig like roks wouldnt they get damaged (no offence intended)



Whatever made you say that :wink: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol:
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Re: What do you guys know about airbag springs?

Post by Aaron »

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