keeping an IRS car level with a load.

Bushbasher · 18-01-2009, 09:53 AM

Having just purchased my first IRS equipped vehicle I don't know what can or can't be done with them. My question is, what is available to stop the ar$e from dragging when you load up the rear via full boot and passengers or a trailer ? Is there air shocks out there or a polyair setup? So far I haven't been able to find anything at all that'll level the ride. Anyone out there know of a system or has one fitted?

Bushbasher

poolkeeper · 18-01-2009, 10:41 AM

: http://www.heasmans.com.au/

These guys may have a solution?
irs I have no idea on sorry

mik · 18-01-2009, 12:38 PM

in the old days it was easy to fix this problem with a pair of air shocks, perhaps have a chat with Pedders or , i found a link for an aussie air bag place they might have an idea http://www.probag.com.au/home.html

Bushbasher · 18-01-2009, 02:42 PM

Quote:

Originally Posted by mik

in the old days it was easy to fix this problem with a pair of air shocks, http://www.probag.com.au/home.html

Don't I know it, I just fitted a new pair of Monroe Gas Riders to my NF 6 months ago which are now useless to me but buggered if I'll let them go with the car(It'll be written off next week when I take it back to the panel beaters), so if anyone needs a set of air shocks for an E series or AU live axle sedan I've got a very good pair with all the fittings now sitting in my shed doing nothing. I'll consider all reasonable offers as I need to now find and pay for a way to hold up the rear of the Sportsman.

Bushbasher

blackers10 · 18-01-2009, 02:42 PM

i dont know of any except the posibility of an air shock

or if you got an airbag setup fabricated to fit the rear end to replace the spring all together maybe give http://livinglow.com.au/ a ring.. they know their stuff (just look at the LandBruiser they made)

good luck

Bushbasher · 18-01-2009, 03:01 PM

The problem with traditional air bag suspension comes back to it fitting inside the spring which it can't do with a strut and the Probag solution seems to be an active system which requires a compressor and air cylinder reservoir which I don't want to firstly, have to pay for and secondly, find room for considering I'll be putting an LPG tank in the boot area already. This, I guess, leaves only one option and that's a passive air strut setup that can be adjusted manually as necessary, and if it were to have fully adjustable damping as well then so much the better. Tracking such a setup down to fit the 'lane could be interesting though so I'll let you know Blackers, how I get on as this little issue progresses.

Bushbasher

**GasoLane** · 18-01-2009, 10:54 PM

IRS is pretty good at taking weight. I'm not sure how low you'd consider dragging, but this is the barge after I stupidly voluntered to move my son (and family) to QLD.

Total weight (on my 650kg towbar) of trailer and junk was well over the tonne with a fully loaded boot, full gas tank and half a tank of petrol...the petrol was needed due to bad fuel economy, but thats another story

Bushbasher · 19-01-2009, 08:00 AM

lol, yup, that's definitely dragging it's ar$e. Apart from being bouncy and wallowy and screwing up the handling and braking, my missus would struggle to see over the bonnet at that angle, haha, plus at that angle you'd struggle to keep your lights from dazzling oncoming traffic as it bounced along.

Bushbasher

05_ENFORCER · 19-01-2009, 08:05 AM

On a side note, a correctly loaded dual axle trailer should not put any weight ON the rear axle!
AND with a fully loaded boot it must have been a slow and scary drive!

Bushbasher · 19-01-2009, 08:13 AM

Quote:

Originally Posted by 05_ENFORCER

On a side note, a correctly loaded dual axle trailer should not put any weight ON the rear axle!

Any properly loaded trailer shouldn't put more weight on the hitch than you could comfortably lift to unhook the trailer IMO

Quote:

Originally Posted by 05_ENFORCER

AND with a fully loaded boot it must have been a slow and scary drive!

my thoughts exactly, and just what I'm trying to avoid.

Bushbasher

Sox · 19-01-2009, 08:52 AM

Post #9 and #10 are both wrong.
The correct ball weight is 10% of the total loaded trailer weight.
So if the trailer itself weighs 300kg and you have 700kg loaded on that trailer for a total of 1000kg, you should have 100kg of ball weight.

Once over around 100kg ball weight, some kind of load leveller bar should be used to transfer weight from the rear axle of the car to the front. These come in many different flavours.

It is important to keep the back fairly level as has been pointed out already.

05_ENFORCER · 19-01-2009, 09:13 AM

Is there a formula or ruling/law on this ?
I would be interested to know where this came from.
Cheers.

rob_liss_lms10 · 19-01-2009, 10:30 AM

Quote:

Originally Posted by Sox

Once over around 100kg ball weight, some kind of load leveller bar should be used to transfer weight from the rear axle of the car to the front. These come in many different flavours.

It is important to keep the back fairly level as has been pointed out already.

Sox is correct,trailer torson bars should be used and afaik is the only way to keep the car level and safe. I have irs as well and when my boot is fully loaded and a full tank of fuel I also drag my butt. I have adjustable shocks so is a pita every time I go away and load up the boot I have to lift the rear about 2cm so sits level, which then makes it sit to high when empty, somewhat of a comprimise has to be made. If you do alot of towing then possibly raise the rear, but if little towing you may have to endure the low butt.
my 2 cents has just been spent.

Sox · 19-01-2009, 11:29 AM

Quote:

Originally Posted by 05_ENFORCER

Is there a formula or ruling/law on this ?
I would be interested to know where this came from.
Cheers.

I don't know where it originally came from, though I would imagine some engineering boffins put there heads together, did some testing, trashed some car/trailer combos and came to the above conclusion.

It's written on every towing guide known though.

I've always stuck closely to that rule and have never had any problems with sway.
Only once was I forced to load in such a way that there was no ball weight, and it had the death wobbles at anything over 80kph.

It's well worth going to the trouble of setting up a trailer and it's load. The difference in handling and safety is very real.
When I'm towing up to 2000kg, I can safely travel at every legal limit in OZ without any sway problems whatsoever. And my cars almost always sit level, with perhaps the slightest rearwards sag.

Rick.

**GasoLane** · 19-01-2009, 11:50 AM

Quote:

Originally Posted by 05_ENFORCER

On a side note, a correctly loaded dual axle trailer should not put any weight ON the rear axle!
AND with a fully loaded boot it must have been a slow and scary drive!

Close. If the trailer puts NO weight on the towbar the trailer will be snaking all over the road!

Yep it was slow -95 to 100kmh, any faster and it used waaaay too much fuel! but not scary at all

mik · 19-01-2009, 10:23 PM

any updates Bushbasher?

blackers10 · 20-01-2009, 08:55 AM

a traditional airbag system that replaces the coil will have no dramas in the rear end..
you can run a set of valves like on your tyres rather than having an airtank and compressor on board OR you can just run a compressor(probably fit it in behind the carpet somewhere or in a gap under the rear end somewhere (just takes a few more seconds to inflate just like your tyres do at the servo from flat)

there isnt a hell of alot of room inside the spring between the shock and spring to fit the load helping bags so dont know how they go

and on the topic of tow bar down weight...my uncle was told not to put more than 60kg of downward pressure on his tow bar he had installed on his NL Fairlane with superlows and standard type shocks and 18" wheels (had a car trailer built for his hotrod) which towed fine up and down the coast

Bushbasher · 20-01-2009, 08:56 AM

no updates as of yet. I've emailed a couple of air suspension places but have yet to get any responses. As soon as I have anything to report I'll post up.

Cheers
Bushbasher

**Mechan1k** · 20-01-2009, 03:52 PM

I am sure Polyair do a set of sorts for the IRS ... then again ... they may only have setup for the live rear axles.

I do know they have setups for Territories (and they are independant rear as well).

**Mechan1k** · 20-01-2009, 03:54 PM

Quote:

Originally Posted by 05_ENFORCER

Is there a formula or ruling/law on this ?
I would be interested to know where this came from.
Cheers.

I am pretty sure it is hidden nicely somewhere within the NSW RTA website.

I found it:
http://www.rta.nsw.gov.au/registrati...ngtrailers.pdf

But doesn't mention about tow ball down weight (but I know that this is mentioned in the Ford Owner's manual of each and every vehicle (but of my utes had it ... and my Territory makes a mention of it).

In the end ... the RTA stipulates .... if the vehicle manuifacturer states a specific weight ratio that you must adhere to it (for newer vehicles).

equal to unladen mass of towing vehicle for unbraked trailers
1.5 times unladen mass of towing vehicle for braked trailers

These still apply for older vehicles without a vehicle manufacturers guideline.

Bushbasher · 20-01-2009, 04:24 PM

Ok, been of the phone and so far bottom line seems to be there ain't no off the shelf units to be had. There seems to be 2 possabilities so far -

1) - this will basically require a combined order of a minimum 100 pairs of fully damping adjustable air bag struts for around the $500 a pair mark before the bloke will bite the bullet and order a shipment from the factory who are demanding a minimum order of 500 pairs before they'll manufacture said units. These units supposedly are USA made.

2 - These are locally manufactured self leveling or manual leveling air bag units fitted over Boge shocks fully engineered and legal for around the $1800-$2000 mark plus $450-ish for the self leveling system; as well as guarenteed to be better than anything you can buy anywhere else.

Interestingly, guy 2, when told about guy 1 and who it was, got a little agitated about guy 1 and went on to say guy 1 was a shonk and all his stuff was chinese copies of other systems and would fail very prematurely and that guy 2 had almost got guy 1 in court over his iffy claims and products. (which were still coming out of China no matter what guy 1 tries to tell you) Guy 2 also said, that if I brought the car down to the shop so he could measure up to see what was required, he'd gladly show me what guy 1 was flogging and let me do a straight comparison apples for apples ( as he put it) as they'd disected guy 1s' bags/shocks/compressors etc. straight down the middle to have a look and show the dodgy componentry......... so that's where I'm up to so far but I'm still looking so I'll keep you posted.

Bushbasher