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Suspension settings

Posted: Sat Jun 28, 2008 10:30 pm
by silatman
Just had a 2' lifted lovell springs, scorched 4 offroad shock, scorched 4 steering damper and rear poly air bags fitted to my 80 series cruiser along with all the bushes blah blah and am stoked with the results.
With the bags down the ride is soft and just seems to mold into the road but pump them up and the back end will bounce over things.

What I am asking then as I am new to this off road game (tradesman with trailer day to day) is are there any basic rules such as soft terrain soft suspension? or hard terrain soft settings?

Any help is appreciated

Posted: Sun Jun 29, 2008 10:00 pm
by silatman
Is the question that stupid that no one will even answer or does it not make a difference, I still don't know
Help please

Posted: Sun Jun 29, 2008 10:18 pm
by Gwagensteve
It's not really an easy question to answer. This is a very complex topic.

Airbags are a bit of a mixed bag. (oops, bad pun :roll:) Basically, you'll have to go though some trial and error to get it feeling the way you want, however, as you increase spring rate by adding air to the the airbags, you actually need stiffer shock valving to compensate. That will be part of the reason the car is bouncing in the rear when you pump the bags up.

Basically, you should only add air to the bags to correct ride height as you add weight. If you are adding pressure to the bags beyond enough pressure to level the car, you're adding too much air and it will get harsh and bouncy.

In relation to spring rate vs terrain, it really depends on how fast you want to travel. If you idle over everything, you can run a very soft suspension with very little lift.

If you want to hit things fast you will need more spring rate to absorb the hits and not blow through to the bumpstops and bounce. However, stiffer springs also require stiffer shocks to control the stiffer springs.

Terrain has a bit to do with it - if you're running long slippery hills, or sand and have to use momentum to throttle your way up, you'll need better axle control through stiffer springs/shocks.

If you like noodling around on technical obstacles, rarely ever punching or "bumping" the car over stuff, and never hitting anything with lots of momentum, you can get away with a very soft setup.

Beyond having enough height to do the job, it's largely down to your driving style and preference, although you can be too soft - if the suspension is too soft, you'll have too much body movement - the car will feel loose and unpredictable under power and on side angles.

Like I said though, it's complex and related to use, driving style and terrain.

Steve.

Posted: Sun Jun 29, 2008 11:05 pm
by silatman
Cheers mate I was beginning to think I must be missing something.
That sheds some light on the matter, at mimimum pressure the car feels fantastic but I need the stiffness when I hook up the work trailer so the arse dont hit the floor like it did before the upgrade to the bags and new bits.
Thanks

Posted: Sun Jun 29, 2008 11:40 pm
by Suspension Stuff
If you are after a softer ride when she's pumped up you can get air bag spacers. This way you don't have to have the bag so hard at the height you want.

Shane

Posted: Sun Jun 29, 2008 11:54 pm
by chikoroll_
one of the most important questions- these bags, are they coil replacements or suspension aids?

if they are suspension aids-
NEVER pump up the bags when the vehicle is already loaded, or the trailer is on, this MUST be done before
if you pump up the bags after it is loaded, the bag will expand sideways into the coil gaps rather than lift it, it will stay deformed until you work the suspension onroad, giving an incorrect angle (or pinching the bag)

however, you can take it to maximum pressure, then lower the pressure to suit once loaded

so, easiest way-
pump them up,
load it up/hook up the trailer,
deflate bags until ride is level
check the pressure, if this is going to be used often (as you said, you will tow often) it will help you to remember what is needed, rather than checking every 5 minutes

Posted: Mon Jun 30, 2008 6:15 pm
by silatman
The bags are just suspension aids as the trailer weighs nearly 2 tons loaded.
Read up on all the do and don'ts before I touched them and so far they have been fantastic.
25 psi and the rear just settles maybe 10mm when the trailer is hitched up.
Going to play with pressures in them now to find a happy medium that will give me a smooth ride but still maintain ride height.