Will I need a load leveler if I fit airbags

[LukeMS]

Hey,
I'm looking at buying a Jayco Expanda Outback caravan which will be towed by my Pajero NW. The caravan I'm looking at getting has a ball weight of 195kg and a max ATM of 2592kg. I'm well aware of the ball weight limitations over 2500kg, and we plan to travel with a lighter payload in the van just to ensure we stay under 2500 ATM.

From reading this forum it sounds like upgrading the pajaro rear suspension and fitting airbags would be a good idea. I do have a question though: If I fit airbags to the rear suspension, will I still need to use a load leveler / weight distribution hitch? Or do the airbags mean this is no longer necessary?

Luke

[Ian H]

Air bags will help reduce sag in the rear but that's all. They don't assist with removing weight from the rear axle which is the problem area when towing a van with a car also loaded up with a fridge and all your gear, plus passengers. I've taken my car and van over a weigh bridge with and without the WDH attached and the results are a real eye opener.

My caravan is 16' single axle and has an ATM of 2250kg, so it's not big.

Without the hitch, I was over weight on the rear axle by 80kg, even though my total weight (van and car) was only about 5000kg. That's around 1000kg under allowable GCM but I was still illegal. It's a problem a lot of people don't realise exists.

When I fitted the WDH, it took 160kg off the rear axle and added 100kg to the front axle and 60kg to the caravan (single axle). At that point I was legal on all measurements. So the hitch does exactly what it is named for...distribute weight. Upgraded suspension and/or airbags do not, they just help level the vehicle.

So in answer to your question, if you don't want to join the people getting pulled over and stopped by authorities checking weights, as is happening more an more, fit a WDH. It's a safety thing as well.

[NTBenny]

I can confirm Ian's response above. I recently had my Paj and Jayco on a weighbridge and when disconnecting the WDH I lost 160kgs from the front axle. With WDH the front axle was 1240kgs, without only 1080kgs. This is with a ball weight of 220kgs and 30psi in my rear bags.

Benny.

[wazznt]

Hey,
I'm looking at buying a Jayco Expanda Outback caravan which will be towed by my Pajero NW. The caravan I'm looking at getting has a ball weight of 195kg and a max ATM of 2592kg. I'm well aware of the ball weight limitations over 2500kg, and we plan to travel with a lighter payload in the van just to ensure we stay under 2500 ATM.
Luke

I agree with all what Ian H said.
PLUS keep in mind that some caravan manafacturers dont weigh the van and stamp the compliance plate before registration and as a result plenty of owners find themselves at or over the maximum van ATM weight before filling the water tanks and cupboards with even just the bare essentials .
Dont fall into that trap .
There is a lemons caravan site on facebook thats worth a look .

[LukeMS]

Thanks for the great advice! Based on what you are all saying it definitely sounds like it would be best to buy a load leveler and see how that goes, before figuring out if I will need to add airbags into the mix as well.

It sounds like the advantage of airbags is just that they will help raise the rear, which will give better clearance and mean the suspension has more travel when going over bumps. Is this right?

[old Jack]

Thanks for the great advice! Based on what you are all saying it definitely sounds like it would be best to buy a load leveler and see how that goes, before figuring out if I will need to add airbags into the mix as well.

It sounds like the advantage of airbags is just that they will help raise the rear, which will give better clearance and mean the suspension has more travel when going over bumps. Is this right?

Airbags in coil springs work by bulging out between the coil wraps to increase the spring rate so the ride height does not drop too much when loaded.

This is why you need to inflate the airbags before you add the extra weight!


By maintaining a higher ride height with a higher spring rate you not get more usable suspension travel before the suspension bottoms out.


OJ.

[Ian H]

It sounds like the advantage of airbags is just that they will help raise the rear, which will give better clearance and mean the suspension has more travel when going over bumps. Is this right?

Not quite. Air bags don't raise the height beyond what the car has now, they just reduce the sag by blocking the gap in the coils as OJ has said.

If you get a WDH, you won't need air bags at all because the WDH will stop the sag better than air bags would.

I have both air bags and the WDH but I don't worry about pumping up the air bags beyond the 5-10psi pressure (which is the minimum you need to keep them in place) when using the caravan and WDH.
I only pump them up to 25psi before I hook up the Tvan which has a ball weight of around 160kg. I can't use the WDH on that because it's an off road camper and you can't have the WDH on if you are going over undulating terrain like a river crossing exit or over whoopsies on a dirt track etc.

[old Jack]

A correctly setup WDH should only transfer back the amount of weight to the front axle as what was transferred from the front axle when the towball load was applied. Often there is way too much load being applied to WDH setups to compensate for soft rear suspension and this puts enormous loads on the WDH and the towbar assembly which does result is failures.


OJ.

[Ian H]

Agree there OJ. I've seen people have so much tension on them that they can almost lift the back of the car off the ground !

I think the best thing to do is get the hitch and then go to the weighbridge. You can then check with it on and with it off and as OJ said, tension it so the weight on the back wheels comes back to about the same as it was without the van.

[green troll]

My 18ft van I had WDH fitted and it was a very nice ride. Took them off for one trip and any up down sections of roads like dips or coming into bridges was a wild ride. Van was only about 2.3T.

[old Jack]

Agree there OJ. I've seen people have so much tension on them that they can almost lift the back of the car off the ground !

I think the best thing to do is get the hitch and then go to the weighbridge. You can then check with it on and with it off and as OJ said, tension it so the weight on the back wheels comes back to about the same as it was without the van.

Ideal tension for a WDH is so the front ride height return to the pre Towball load height.
From my research the Anderson WDH which incorprates an anti sway feature and is more tolerant to rough and undulating roads and spoon drains, so it would be worth considering if you are in the market for a WDH?

OJ.

[2bad4u]

When I first got my Pajero I used a WDH with my van. This was good but later I also fitted airbags and this helped to "settle" the caravan down ie: down bumpy roads the airbags just settled the rear end down significantly. I ran with this setup for about 5 years and then last year I had the suspension upgraded and decided not to put the airbags back in and the car / caravan handles brilliantly but I still run the WDH even with the upgraded suspension.

To answer your question, a WDH and airbags aren't necessary and will depend on how your combination handles. I would go WDH first and then airbags if needed (or suspension upgrade and skip the airbags all together). Most caravaners will agree that a WDH is a good investment.

[Ian H]

To answer your question, a WDH and airbags aren't necessary and will depend on how your combination handles. .

It's got nothing to do with how it handles. Mine handles great with or without the WDH.

It's a matter of being legal and without a WDH, you aren't legal in 90% of cases. being legal also means no issues if there's an insurance claim, never mind the weight police out there these days and the 2 main targets are Pajeros and Prados.

You probably don't realise but even with a 20K forward fold camper, which is so common these days, the ball weight can be around 180kg and with a loaded Paj, you are still most likely illegal on the rear axle.

[2bad4u]

If your setup is illegal, then you should be looking at a new car / van. A WDH is not designed to correct an illegal setup, they are designed to bring stability and safety to your combination which is why it has everything to do with how your setup handles and nothing to do with legalities. My combination is legal with and without a WDH but it handles a lot better with the WDH.

It's a bit like saying add weight to the rear bumper of your van to reduce ball weight, it may make your setup legal but you're asking for trouble and only providing a bandaid solution rather than fixing the problem.

With insurance claims, there is no way of proving what the ball weight was following an accident so they work off ATM, GTM & GCM to work out if your setup was legal and even then they have to make assumptions about how much everything weighed. So I stand by my original statement that a WDH and airbags aren't necessary and will depend on how your combination handles.

If your combination is illegal, then look at a different van.

[Ian H]

A WDH is not designed to correct an illegal setup, they are designed to bring stability and safety to your combination which is why it has everything to do with how your setup handles and nothing to do with legalities.

Then we'll just have to agree to disagree.