Age old question - WDH or uprade suspension for towing

[Cessa]

Gday all
Towed my van for the first time since buying the NP300 and found it pretty average in the suspension. The rear did sag and the front lifted about 1.5 inches or more. Found The ute slightly wandering on rough road and thoughti need to fix this.

I have towed my van with other vehicles with no problems butthey had air bag suspension.

What are your thoughts and experiences. Tow ball weight is aroud the 200 mark. Van weight loaded is about 2.4 tonne.

I have the STX model.
Cheers

 

[Tonba]

Interesting. I plan to do alot of towing with my Nav too.

I think some slightly uprated springs would help without compromising comfort too much.

Fulcrum now do suspension and bush upgrade kits, i might have a talk to them about it.

 

[Old.Tony]

WDH should be mandatory. No question about it. Suspension won't - and cannot - fix it. It can mask the problem, but all you're doing by lifting the rear (higher springs or air bags) is making the car sit more level. The actual axle loads are still all buggered by the weight behind the rear axle - and you won't be able to tell until you've either weighed your front and rear axles hitched and unhitched, or you have an emergency and the thing comes unstuck in a big way.

When you place 200Kg about a metre behind the rear axle, you've got a decent amount of weight with a decent lever trying to twist the front of the car up using the rear axle as a pivot point. Raising or lowering the pivot point doesn't change anything - the lever is still there, and still has the exact same effect of pushing the back down - which raises the front up.

Setting up the WDH the correct way is vital. Here's how I did mine.

1) Park the car and van on level ground, engage the brakes and unhitch.

2) Using a spirit level, make sure the chassis of the caravan is level (slightly nose down is preferred to slightly nose-up).

3) Measure the height of the ball socket and adjust the height of the WDH to suit.

4) While the WDH is loose, adjust the top plate so that it is level with the ground.

5) Bounce the car up and down to make sure it's settled nicely and measure the distance from the top of the wheel arch to the wheel hub (not the rubber, but the metal part of the wheel). Repeat this for all other wheels, writing the results down.

6) Hitch up the van again (without attaching the bars) and note the wheel arch heights again (give the car a little shake to settle the suspension first, again).

7) It's now time to crank the bars into position by attaching the chains. You'll have them set up correctly when the height of the front wheel arch settles about (within 2-3mm) the same amount as the back.

8) Once done, mark the links in the chains that you need to use and you're done.

The first caveat on WDH usage is that not all chassis can withstand the torsion induced by them, and some manufacturers will even give you warranty grief if you fit them. My own Navara has had no difficulty - the dealer was aware that I was going to use a WDH and recommended a change in tow hitch because of that (5 bolts per chassis rail rather than 3).

The second caveat with a WDH is going over steep driveways, causeways, wheel ruts or any significant twists between the tug and the van. The spring bars don't like it, and you certainly don't want to keep them awkwardly-tensioned for any length of time.

 

[Cessa]

Thanks od.Tony, good information. I supose there is no magical answer that will balance the car effectively and can handle irregular road angles. My last 2 cars that towed the van were bigger cars and had air bag suspension and they handled the weight well but the Nissan seems to suffer a bit. To me this is strange as the ute should be able to handle 1tonne where the other vehicles could not but the ute suffers from the weight issue.
Your explanation of how the extra weight behind the axle makes sense but still would have thought the ute should handle the extra weight better.

 

[Old.Tony]

At first you might expect that it could do it easily, but it's the position of the load that's the issue. 1 tonne of gravel sitting in the tub will be fairly evenly spread over the tub placing the load pretty much over the rear axle. Since there's no longer a pivot (because there's no distance between the weight and the axle) there's no problem with the nose of the vehicle coming up - all that happens is the tail end of the car sags. And on stock springs, it sags to the bump stops.

The main issue is with braking/steering. Generally, something like 70% or more of your braking force comes from the front wheels. As the car brakes, weight shifts forward pressing the front tyres into the ground, allowing an even better grip. If you've got a couple of tonne of caravan on the back, its going to transfer its weight forward too, which means even MORE downwards pressure on the towball and less force keeping the front wheels down doing their business - it is a double-whammy.

And too often, people find out about it just before the impact.

As for the larger vehicles - they're larger! It's only natural that they're going to handle loads better. We're actually asking quite a bit of our "little" trucks to pull - and control - up to 3 tonnes behind it. They can do it, but we have to be very conscious of the caveats of doing it and the tools that we can use to avoid it - like the WDH.

 

[DesertHucker]

if your comparing a SUV to a ute, the SUV has its tow ball closer to the rear axle, bringing the mass and pivot point closer to the axle.
On the ute it is farther away from the axle, therefore the pivot point will greatly increase the axle weight.
Sort of like a sea sore effect.
So your 200kg on the tow ball could be 300-400kg on the rear axle on the ute.
on the SUV it could be 250-300kg on the rear axle.

 

[Cessa]

That is a good point also, didn't think a small margin in length would have that much of an impact.
So definitely looking at a WDH option to fit. I know there are many around but the next big question will be how on earth do you fit one to the trailer / van when the jockey wheel is in the way?
Surely this is not an isolated issue? From most of the pics i have seen, the trailers / vans dont have a jockey wheel fitted which then brings me to the next obvious question???
Is there a way to integrate them both especially on an A fram that has not alot of spare room on it.

 

[stewydz]

Hi. I have just finished wiring and fitting air bags for the rear springs. we are about to go on our fist trip with the camper.

Can anyone tell how the auto goes towing.?? Any Over heating issues?? Has anyone fitted a tranny cooler.?

We are in CQ so its generally warm.

 

[Old.Tony]

The auto is actually recommended for towing. We tow a 2.5T caravan nowadays, and we just take it easy up hills (changing gears manually) to prevent overheating. I have fitted an external transmission cooler but it's not just to assist in cooling, it's also to prevent cross-contamination of engine coolant with the transmission fluid.

 

[mike1303]

What's a wdh?


Sent via smoke signals

 

[MANNING]

What's a wdh?

It's a Weight Distribution Hitch

 

[Cessa]

Hi. I have just finished wiring and fitting air bags for the rear springs. we are about to go on our fist trip with the camper.

Can anyone tell how the auto goes towing.?? Any Over heating issues?? Has anyone fitted a tranny cooler.?

We are in CQ so its generally warm.

I agree with old.Tony, Just ake it easy, use the manual shifter for going up steepish hills. The 2.3 does a pretty good job but you definately know your towing so dont push it too ha r d and it will look after you. As for possible temp issues, i didnt have any but if your in doubt, worth the extra pennies to save you the pounds later.

 

[Panuara]

Put upgraded Spring set from Zordo on my d40 ST manual and then use an Anderson WDH. Brilliant bit of gear, no sway at any speed. Just did 11000k through west nsw, sa, central Aust Tennant creek then to Townsville and back to TAMWORTH. No issues at all from road trains, strong winds , bumpy roads. Towing a 2.7t van.