WHD and Polyairs (or similar)

Submitted: Tuesday, Sep 09, 2008 at 17:49
ThreadID: 125029 Views:3330 Replies:3 FollowUps:1
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A separate post to avoid hijacking my own thread...

I'm after comments from those of you who run WDH and Polyairs on the rearr (or similar).
The objective of the WDH is to transfer load to the front axle and keep the vehicle "level", but at an overall lower level than without the BT attached, due to settling of the entire front and rear suspension with the vehicle load.
The objective of Polyairs is to stop the back suspension sagging by taking the weight on the Polyairs, but not to transfer load to the front axle. The weight is taken on the rear axle.
Since WDH can't be attached all the time and I don't like the rear-end sag when they're off (e.g. off-roading with the BT), I'd like to have Polyairs fitted. I've used them on a few vehicles before and found them very good.
How do you guys make this work? I don't want the Polyairs to be interfering with the WDH doing its job. What pressure do you run in the Polyairs withe the WDH engaged? With the WDH "off"?
Any other hints, suggestions or experience?
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Reply By: Sooty & Sue - Tuesday, Sep 09, 2008 at 18:53

Tuesday, Sep 09, 2008 at 18:53
Here goes .. no expert but this works for me.

I have Firestones on the rear (F250 dual rear wheel). I use WDH on the bitumen (of course) with about 50psi in the bags. On a dirt road with corrugations I take the pressure right down, sometimes to about 20psi, this provides a much more fluid ride for the van and allows the suspension on the truck to work in harmony with the van's. The effect of this is to transfer much less jarring and jolting through the tow bar to the A frame of the van. In short a much smoother ride. Of course if there is to be some more serious angles involved eg crossings etc then the WDH come off. Hope this helps.

AnswerID: 575912

Reply By: Sundy & Cyclone - Tuesday, Sep 09, 2008 at 18:55

Tuesday, Sep 09, 2008 at 18:55
We have been towing our 18' BT for about 5 years now and over a mixture of roads & tracks and at speeds that the conditions dictate. Rarely go over 90kph on the bitumen though as we're never in that kind of a hurry, and if we do it's usually to relieve the frustration of following traffic.
We used WDH's on previous vans but never felt the need for them on the BT either for levelling or stability. Our first 100 series had heavier rear coils with heavy duty shock absorbers. The springs had about a 1 1/2" lift and sat up a bit when not loaded or hitched up but was level and travelled perfectly when towing.
On our current 100 series we decided to give air bags a go (mainly because Jude didn't like the way the previous "Cruiser" sat up at the back when unloaded), we run them at 5 - 8 psi when the load is off and at 35 psi when loaded and hitched up and the rear tyres to about 42 psi. Rear springs are standard but thinking of upgrading them as the van, with this set up (airbags), does dip slightly but we still do not have any stability problems and the slight "dip " I know we can over come with a more suitable spring choice.
Anyway, it works for us and we don't have the creeking and groaning the WDH's produce when turning and don't have to decide if we should have them on or off depending on track/road conditions..
So thats about it, hope it's a help if not food for thought,

Cheers Judy & Tony Quebec 1257 (Sel 1257)
AnswerID: 575913

Follow Up By: Fred & Marj - Wednesday, Sep 10, 2008 at 05:23

Wednesday, Sep 10, 2008 at 05:23
Have been down this track before and raised a few hackle ! but I agree with Sundy - we have an identical setup except have an upgraded front suspension to stop the "droop" and now some outback experience and have found the BT to behave perfectly on and off road in fact it is perfectly stable on all terrain and all speeds. Happy to discuss with all and sundry at the rally but not really interested in dabate as I guess it is down to how the van is setup re weight distribution and the tow vehicle is also setup.

i will now duck


Helen & Wayne

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FollowupID: 850126

Reply By: Frank Aus - Wednesday, Sep 10, 2008 at 05:51

Wednesday, Sep 10, 2008 at 05:51
HI Sooty,
I agree with the comments posted and each to their own, I use a wdh hitch and only a 16ft van and this to stop the porpose effect in the single cab effie, i run my rear air bags at 50psi and my front at 25, when fully loaded and 5-8 psi when running on empty, i bought my bags out of the states, front and rear landed here with a full set of Rancho shocks for $500 less than i could buy here for the bags alone.
AnswerID: 575914

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