WDH vs Air Bags vs Lift Kit

macpanda

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May 26, 2022
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Hi All, hoping for some advice from the brains trust!

I am heading off on a 7 month half lap of Aus with my wife and kids (6 and 8) in December. I think we will cover around 20,000 to 30,000kms over the trip, mostly sealed driving but possibly some dirt tracks and beach tracks (with the van unhitched!). We have a 2010 18.57-6 Expanda (Ball weight 164kg, ATM ~2500kg), and i am on the look out for a Hilux or D-MAX (0 - 5 years old, sub 100,000kms). I've previously had a Jayco Eagle, and i am a bit clueless about what i need to manage the weight distribution (sag) and suspension on the tow vehicle.

I have a weight distribution hitch which came with the van. I've tested it on my current vehicle, and it brings the sag back to close to level. I am not sure if this will be sufficient, or whether i need to fork out for air bags and/or a lift kit on the rear. I will have another 200 - 300kg in the tray of the ute, but nothing excessive as i'm keeping a keen eye on my weights (which i am well under). Any suggestions or recommendations?
 

MDS69

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Jul 6, 2014
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I would get suitably rated leaf springs and matching shocks. Leave the WDH at home and stay away from airbags on a dual cab ute. My opinion only. When you return swap out the leaf springs for your originals or a lesser rated pair for every day driving as the new ones will give you a harsh ride on a lightly loaded or unladen vehicle. Money well spent for a proper solution. Again my opinion only.
 
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Drover

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Agree with @MDS69 , with an ATM of 2.5t I would be upgrading the springs and shocks on the vehicle, unless the one you get has had it done, the vehicle will certainly ride better, just don't make the same mistake as many and go the HD set up, thats ideal for tradies with tons of junk always loaded up, go the mid range set up, good for towing and all round driving but the change must be the whole lot not just the back ........... fitting air bags to stock suspension is a recipe for disaster and shouldn't be needed with a decent suspension set up ................ Most stock suspension will just sag away with a load and is rubbish, all my vehicles the suspension is the first bit to be replaced...
As for vehicle HiLux or D Max just check them out very well, should come with some extra bits as well, be wary of clutches in manuals as most folk now love to slip the clutch and burn the crap out of them.
 
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millers

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Mar 25, 2011
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WDH are in a lot of cases a "religious war". I have an 18 outback and have towed it with a R51 Pathfinder and BT50. On the R51 it needed the WDH and I needed to adjust it to get the balance right. Also added air-bags to lift the rear when towing.

I use WDH for the BT50 as well, but not to the same extent (ie it is tension up less). Utes will always have an issue with how much you load the back up and how much you think that load is normal. I would be doing some trial runs and seeing how well it all sits together.

In my opinion,
- WDH is not a replacement for the right suspension to support the load (both front and back).
- But also suspension upgrades do not make the front heavier when you add ball weight when towing (or load the back)
- Additional items at the front can compensate for load at the back (bullbars, winches etc)

If in the final setup, you consider that the front is too light, then add the WDH and adjust to make the steering heavier (to your liking)

If in the final setup, you are happy with the weight balance and steering without WDH, then do not fit it.

Note: no mater what suspension upgrades you do:
- Weight/load added after the back wheels applies downward force on the rear and upward force on the front (proportional to the distances from the back wheels to the load and the wheelbase
- Weight.load added between the wheels applies downward force on both front and back (proportional to the position along the wheelbase)
- Weight/load added before the front (reverse of towing weight) downward for front and upward for back

It is driving preference as to how you balance the setup, but once you go beyond the limits disaster will occur.
 
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Drover

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The biggest thing is most people set up the WDH wrong and when they upgrade there suspension go for the HD type when its not needed, they all need to work together to be a solution...... If the rear end sags more than 30mm then a WDH is needed, end of story, as in most cases the front will lift as much as 45mm, leaving very little travel left in front end...

In my Colorado originally it would sit nice and level no need for WDH, undulating roads it didn't porpoise at all but what I did find was at speed on afreewa y, abit of headwind, the wind would get under the vehicle and create lift and I woudl get front end float because the back had dropped with van and the foront ;ifted to ;eave bugger all travel, replace suspension and problem solved though i did keep the WDH but with small tension, lot more stable fore and aft on rough old rural roads....... The WDH isn't just for trowing load to the front it will also stop porpoising where the tug will rock for and aft, often upsetting the steering and balance and throwing you into a table drain, really bad and the only way to fix is slam on van brakes only or hang on.... The Jeep the Nivomatt shocks bring it all back level in about 100 yds but still use the WDH to smooth things out.......... No 2 rig set ups are the same so opinions vary,
 
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jazzeddie1234

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May 19, 2016
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I tow an 18' full height jayco of similiar weight with my 2015 dmax. It was my first experience of towing a load greater than the tug and I found it really freaky. I'm a bit on the sensitive (and low risk) side when it comes to vehicle dynamics so I asked around what was going on. At that stage I had a 40mm lift and airbags.

The dmax (like other utes) has a long distance between the rear axle and towball and this lever effect created a squirm sensation all the time in the back. I also drove along an undulating road at 80kmh and (felt like) I nearly lost control because of the porpoising- again due to the leverage from the towball to the rear axle.

I found a quiet road and carefully conducted a few LOW SPEED sudden steering changes - just to test the overall stability. The general rule is the sway should self correct within a couple of swings - otherwise you are just masking a problem that could eventuate at the worst possible time. It did but felt horrible!

Fitted a wdh (after swearing I never would) and a friction coupler which attaches to a second, small towball on the A-frame and WDH. Those 2 , in my opinion made a huge improvement to the feel of the setup. The other thing pointed out to me was the side movement in the tyres. Put your foot on the side of the towball and push the back sideways as hard as you can while watching the flex in the tyre sidewalls.

So now I tow with 50psi (hot) in the ute rear and the caravan tyres, use the wdh everywhere - even on dirt roads except where there are undulations that will stress the wdh bars (like a culvert or mound) - use the friction coupler only on the blacktop, put 25psi in the airbags, keep all the really heavy stuff in the ute where possible.

This is just my experience and there are other raging debates about how bad a wdh is - so good luck

And PS my dmax is a bit under powered for 2.7t and rarely drops into top gear . Newer models have a bit more go
 
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Drover

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@jazzeddie1234 was right to mention tyre pressure, it is one of the number of things that is part of the whole make up and is often forgotten, all vans will behave different at first, once the tyres heat up things will become more stable, checking your van and tug tyres once they warm up shoould show they are around 4-6psi more than when you started any less you have too much air, more not enough easy, adding more to the front tyres isn't really needed either even with a WDH and a "P" rated tyre will squirm far more than a "LT", the more aggressive the tyre pattern the more it will move as well, van movement and stability is more than a WDH..................... Also quite a number of manufacturers require a WDH when the tow ball weight is over a certain amount, because while vehicles will have a load rating they fit soft ride suspension which isn't up to par for it.... the bent chassis vehicles I have seen all seem to be well over loaded before anything put on tow ball............. get to view a few up here on the tow truck.
 
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Prydey

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Apr 24, 2018
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WDH, airbags and lift kit all do different things. Don't let anyone tell you otherwise. A good post above by miller explaining some of the things each will do.

Don't get overly carried away trying to fix a bit of sag. It's only once it starts to negatively affect handling that you need to worry. Given you are going to be towing a fairly heavy van it's a good idea to get your load distribution sorted out, making sure you aren't too light on the ball weight or over loaded on the rear axle etc. A wdh isn't a solution to an overloaded axle. Likewise heavy duty springs will have no effect on front axle weight being reduced.

Any particular reason you are only looking at hilux or d-max for your tow vehicle? Ford ranger is a better tow vehicle than either of them. No more badge tax on ranger than hilux..

Most importantly, have fun.

Forums are great but sometimes you can end up more confused than when you started. What I would say is take all the advice on board but then only apply it if it suits your own situation. No point setting your car or van up to suit someone else.