18' Series My tow vehicle bounces while towing

Doc

Doc

Well-Known Member
May 2, 2016
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Hobart, Australia
You my friend, are a prime candidate for a WDH. The Triton has a very long back-end. The towball is a looooong way from the back axle, and this creates a very long lever effect, lifting the front of the vehicle off its suspension. While airbags and heavy springs will prevent sag at the back axle, they will not prevent lift at the front. What you are feeling sounds to me like the van is pitching the vehicle, using the rear axle as a fulcrum. Your stiffened rear suspension is simply serving to increase this effect.

edit - by stiffened rear suspension, I mean that when the rear suspension is sitting down on the helper springs, there is very little compliance left in the system.
 
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KECL

KECL

Active Member
Aug 16, 2016
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I agree will most comments a WDH is the way to go. I also installed Air bags in my Prado; I did this as the Prado has (in my opinion) a soft back end and almost any weight causing the back to droop even a full load of passengers. I normally use around 5 psi for unloaded conditions and 18 psi for the caravan (16.49.1). I purchased my WDH from Mister Hitches (www.misterhitches.com.au), they were under $500 and so cheaper than the Hayman Reese WDH system. The booklet for installation procedure is pretty good so could install myself.
 
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Lozza T

Lozza T

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Aug 13, 2016
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Purchased and fitted a RAPID BAR 600 WEIGHT DISTRIBUTION KIT - 275KG BALL CAPACITY. From Road Tech Marine.

I fitted the tow hitch 1st and tested it on the freeway. Definitely an improvement with the hitch being 130mm higher.

I then proceeded to install the bars and chains. I managed to get the front of car to remain at the exact same height while the rear of to Triton only dropped 10mm while under load of the van.

2nd test drive improved results again. However there is only minor hopping which generally happens while going over a dip in my road.

So I am satisfied with the WDH and just in time for the Boxing Day departure.

Thanks to all for your advice and help.

Here are some pics....

Picture (367).jpg Picture (368).jpg Picture (370).jpg Picture (369).jpg
 
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warren cook

warren cook

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Sep 18, 2016
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Lozza T said:
Purchased and fitted a RAPID BAR 600 WEIGHT DISTRIBUTION KIT - 275KG BALL CAPACITY. From Road Tech Marine.

I fitted the tow hitch 1st and tested it on the freeway. Definitely an improvement with the hitch being 130mm higher.

I then proceeded to install the bars and chains. I managed to get the front of car to remain at the exact same height while the rear of to Triton only dropped 10mm while under load of the van.

2nd test drive improved results again. However there is only minor hopping which generally happens while going over a dip in my road.

So I am satisfied with the WDH and just in time for the Boxing Day departure.

Thanks to all for your advice and help.

Here are some pics....

View attachment 46818 View attachment 46819 View attachment 46820 View attachment 46821
Click to expand...
Good on ya,

It will give you so much more confidence on the road.

You look like you could go another link matey and not sure if it's the angle of the picture but maybe move the bracket back an inch as the chains look at an angle, they need to be straight (although not sure about that brand WDH)

@ChrisFatboySydney sent me a link to this WDH the other day. He will appreciate any feedback from your first journey with it.

Just double check how you have packed the van for the bounce in case you have something heavy at the back of the van, this will exaggerate the bounce affect your feeling.

Have a great trip on Boxing Day, where are you off too?
 
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C

ChrisFatboySydney

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Feb 29, 2016
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warren cook said:
@ChrisFatboySydney sent me a link to this WDH the other day. He will appreciate any feedback from your first journey with it.
Click to expand...

I went past road tech marine and the hitch fits the isuzu but the overhang is much further out than the original ball. It really needs to be shortened about 3-4 cm and a new hole drilled for the pin.

It is really heavy and made from solid steel so should support pretty much anything.

At $399 well priced compared to others.

CK
 
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Lozza T

Lozza T

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Aug 13, 2016
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Hi CK. Just checked my tow ball position and it could probably move in about 3 - 4 cm too. Do you think it would make a difference?
 
C

ChrisFatboySydney

Active Member
Feb 29, 2016
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Lozza T said:
Hi CK. Just checked my tow ball position and it could probably move in about 3 - 4 cm too. Do you think it would make a difference?
Click to expand...

My understanding is the more back it is from the rear axle the greater the impact.

My Isuzu has specific recommendations around distance from the rear axle. The WDH exceeds this and sticks out much more than the standard ball.

I don't know how much the impact would be for such a small amount but as my receiver is very short I need to cut it in order to have it fit properly anyway.

Ck
 
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Bellbirdweb

Bellbirdweb

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Jan 24, 2014
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Just a little foot note on this thread.

I haven't used a WDH as the van has always towed well, and been level on the cruiser with HD suspension and shocks and airbags.

On day 1 of the trip I'm currently on, I noticed 1 of the bags drop to 0 psi. I thought it was a hose, but the bag actually developed a hole in it.

Having now driven 2000km on 1 airbag, it's amazing the difference it makes (in a bad way).

The back of the car is down and the van is downhill.

Front is now really light and is exciting when going over bumps in the road.

I will be replacing the air bag, but it's obvious they are doing a hell of a lot of work, so I'll now be investigating a WDH to ease the load on the airbags.
 
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achjimmy

achjimmy

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Jan 24, 2011
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Bellbirdweb said:
Wasn't aware of the Kevlar sleeves, will certainly check that out.

The bag that went was 12 years old, so didn't do too bad.

Where do you get the sleeves from ?
Click to expand...

Airbag man an option on just about any airbag. Also allows extre pressure
 
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