Water tank relocation. Is it worth it ?

Submitted: Monday, Apr 16, 2012 at 11:50
ThreadID: 94931 Views:3609 Replies:9 FollowUps:12
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Hi All, I need to put my tow ball weight on a bit of a diet. Currently at 260kgs which is 10% of van weight so thats ok but i would like to get it down to about 240kgs. i have 1 95 litre water tank placed just forward of the front axle, if i move it to between the axles is there any real change in tow ball weight to justify the PITA relocating job. Has anybody done it and was it worth it ?. The weight was checked with both gas bottles full, both water tanks full, and the van in take off mode minus food and clothes.

Cheers Warren
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Reply By: ozjohn0 - Monday, Apr 16, 2012 at 13:06

Monday, Apr 16, 2012 at 13:06
Warren,
If there any particular reason you need to reduce the ball weight by 20Kg?
Ozjohn.
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Follow Up By: Warren B - Monday, Apr 16, 2012 at 15:24

Monday, Apr 16, 2012 at 15:24
Christ this answer is going to stir up a hornets nest sorry in advance. I would like ( if i can ) to get away from WDH, and i reckon if i drop 30kg off the ball may just do it. I'm not real smart ordered the van when we had the cruiser then sold the cruiser 2 months befor van arrived and got a D-max. Loovvvvvvvvve the D-max. max has been fitted with steel BBar and winch and lifted 55mm with performance suspension kit. If i have to use WDH then ok the world wont stop and i'll just have to live with them.
Warren
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Reply By: Allan B (Member, SunCoast) - Monday, Apr 16, 2012 at 14:01

Monday, Apr 16, 2012 at 14:01
Hi Warren, Certainly moving the tank rearwards would lower the tow ball weight, possibly even more than 20kg. At least, mounted between the axles would mean that the tow ball weight would change little, if at all, between tank full and tank empty. Only you can evaluate if the relocation is worth the trouble.

Have you compared the tow ball weight difference between a full tank and an empty tank? That would give you a fair idea of the effect of relocation.

Cheers
Allan

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Follow Up By: Warren B - Monday, Apr 16, 2012 at 15:33

Monday, Apr 16, 2012 at 15:33
Hi allan,
Just when we were going to drain the tanks murphy showed up in the form of 4 trucks all wanting to use the weigh bridge. Hadn't been a truck for 2 hours prior so just weighed with both tanks full as i wanted the gross weight as well.

Cheers warren
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Reply By: Wayne david - Monday, Apr 16, 2012 at 14:11

Monday, Apr 16, 2012 at 14:11
Giidday Warren - I've been mulling over solutions for the very same issue.

I've not thought about moving the water tank but I have thought of adding a swing away rear wheel carrier. Not too sure of all the pro's & con's of such an idea but I do know that cost is one downside.

Does that idea grab you?

Cheers - Wayne
AnswerID: 483275

Reply By: splits - Monday, Apr 16, 2012 at 14:32

Monday, Apr 16, 2012 at 14:32
Warren.

Read through these two links. There may be an advantage in reducing the weight but there is a lot more involved in it. I can't find anything better on the net than this to explain it.

http://www.caravanandmotorhomebooks.com/articles/caravan_dynamics_cw.pdf

http://www.caravanandmotorhomebooks.com/pdf/vehicle_dynamics_complete.pdf
AnswerID: 483278

Reply By: Member - Old Girl - Monday, Apr 16, 2012 at 14:32

Monday, Apr 16, 2012 at 14:32
How about filling 5 jerry cans and placing them in the middle of the van . Weigh it to see if the ball weight has changed.
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Follow Up By: Warren B - Monday, Apr 16, 2012 at 19:55

Monday, Apr 16, 2012 at 19:55
Hi,
Dam simple idea but would work,

Thanks warren
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Reply By: Ross M - Monday, Apr 16, 2012 at 17:55

Monday, Apr 16, 2012 at 17:55
G'day Warren
Just a comment about the ball weight you are trying to reduce.
The most recent Jayco caravan pamphlets show a ball weight less than the 10% everyone seems to blindly follow.

Theirs is about 8% on their newest range and would indicate that 10% is just a figure thought of by someone and so sheep follow.

By trial and error, without risking your life, you should be able to reduce it and still have adequate control.
290 kg is alot of weight especially for a smaller vehicle like the dmax. Most of this size vehicle claim a 3ton tow ability but this is in ideal conditions and IMO really pushing the limits as the van weighs in at a figure significantly above the tug weight.
To try and compensate for 290kg with a WDH on a Mazda/Ford/Navara/Collie/Dmax is just asking too much of the chassis design strength. All ok if flat travel but trouble if you hit the ups and down bits, particularly at speed where the caravan smacks the tug around via the towbar and WDH. Think bend and crack of chassis if overload forces become too much.

To safely reduce the ball weight is a good idea.
Be careful as the 55mm lifted suspension won't be there with a van in tow and the nose up effect with van will cause the camber of the front wheels to alter and the toe in to also change. If used for 1000'skms in this condition abnormal tyre wear WILL happen. Try to make the front suspension ride height as it is without the van for best results. Not so critical for beam axle Lcruiser though.

Ross M
AnswerID: 483301

Follow Up By: Warren B - Monday, Apr 16, 2012 at 20:31

Monday, Apr 16, 2012 at 20:31
Hi ross,
The van weighs 2680kgs ready to roll without food or clothes the ball weight is 260kgs. the reason i are looking to lower the ballweight is for the reason you said its only a D-max and while it does a fantastic job if I can help it a bit I will.
I don't need to put an excessive amount of tension on the WDH to get the front back to normal but its still tension I dont want. I want another solar panel and battery so batteries will have to be relocated another 20kgs moved backward
I Have a few million k's under my belt both long haul and local. and the van handles / tracks / steers fantastic ( wish my quad dog handled this well ) so i am reluctant to alter van dynamics to much. just 30 kg's would be ok.
Warren
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Follow Up By: ozjohn0 - Tuesday, Apr 17, 2012 at 08:42

Tuesday, Apr 17, 2012 at 08:42
The weight of adding another solar panel and battery will have to be included in the trailers payload allowance, and will the loaded trailer exceed it's ATM?
OJ
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Follow Up By: ozjohn0 - Tuesday, Apr 17, 2012 at 08:45

Tuesday, Apr 17, 2012 at 08:45
Ross,
Thee ball weights on the Jayco Vin Plate are for the unladen van (TARE) as it left the factory and have absolutely no refection on what the ball weight will be for a loaded Jayco.
The final ball weight is detirmed by how the weight is distrubuted in the van.
Ozjohn.
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FollowupID: 758593

Follow Up By: Nomadic Navara - Tuesday, Apr 17, 2012 at 17:50

Tuesday, Apr 17, 2012 at 17:50
Ross

Further to what OJ said, the ball weight on the van is just that of the empty van. Most vans ball weights increase significantly when you load them up, particularly those with big front boots.


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Follow Up By: Nomadic Navara - Tuesday, Apr 17, 2012 at 18:10

Tuesday, Apr 17, 2012 at 18:10
Quote "To try and compensate for 290kg with a WDH on a Mazda/Ford/Navara/Collie/Dmax is just asking too much of the chassis design strength. All ok if flat travel but trouble if you hit the ups and down bits, particularly at speed where the caravan smacks the tug around via the towbar and WDH. Think bend and crack of chassis if overload forces become too much."

We have seen quite a few reports of bent chassis. How many of these have occurred with WDH in operation?

Most (if not all) have occurred with very heavily loaded twin cab vehicles and often with off road trailers. Also, how many of these casualties have had involved air bags?

If you have a fair bit of weight in the tub the WDH will be of assistance to countering the effects of the load behind the axle.
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Follow Up By: Warren B - Tuesday, Apr 17, 2012 at 20:06

Tuesday, Apr 17, 2012 at 20:06
Hi O.J. Yes the van is over the ATM fully loaded, but such is life i don't really need an extra panel can survive 4 days before firing up the genny Just wishing. like i said at the start would like to ease the ball weight a bit to do away with WDH but if i have to use them i will, the world wont stop turning.
warren
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Reply By: Rockape - Monday, Apr 16, 2012 at 18:38

Monday, Apr 16, 2012 at 18:38
Warren,
i wasn't going to answer this post until you explained why you wanted to cut back on the tow ball weight.

What you want to do is your choice ad I have no problems with that. A properly setup rig should not need one. Just remember that the weight you place on your rear axle will take weight off your front axle.

Moving the tank back will not do very much to your tow ball weight as it is close to the axle already.

My suggestion is get the weight out of the front.

Have a look in your boot and check what you have never used. Ditch it or relocate some of the weight rear wards.
How many plates and cups , pots and pans do you need.Do you have a full annexe in there that has never been used.
Can you move weight rear of the axles.
I won't go into all the things that can be shifted or removed but if you can do it.

Have a good think about it,

RA.

AnswerID: 483304

Follow Up By: Warren B - Monday, Apr 16, 2012 at 20:44

Monday, Apr 16, 2012 at 20:44
Hi RA,
Haven't got much in the way of excess and don't have an annex we don't use. The van has all the brackets to locate the tank between the axles just wanted to know if it was worth it as i'm close to not needing a WDH but not close enough.
Warren
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FollowupID: 758562

Reply By: snailbait (Blue mntns) - Monday, Apr 16, 2012 at 19:43

Monday, Apr 16, 2012 at 19:43
Hi all
Its not the ball weight you have to fix it is the weight on the front suspension
The way to do it is to measure the distant from the ground to the eyebrow ie the wheel arch, that ie back and front

Then add the caravan to the tow vehicle then measure the front and rear eyebrow again if the difference is more that 10 or 15 mm then you have to add the WDH or add more suspension to the rear suspension ie air bags

If you have you caravan sticking the front up in the air of your vehicle you will have less braking on the front and this could be disartrase. The ball weight is to do with the weight on the rear axle if it is too much you may break the diff or the chassis like i saw when i was up the cape completely broke in half.

If by moving things around to make the caravans be able to have no WDH how many other people would have done it.
Caravan manufacture would have done it before now.
Terry
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Follow Up By: Warren B - Monday, Apr 16, 2012 at 21:01

Monday, Apr 16, 2012 at 21:01
Hi Terry, as i explained in previous follow up I don't have a lot of brains ordered a van for landcruiser then hook it up behind D-max. The front raises almost 20mm with van attached about 18mm to be exact. I could do the air bag thing but don't want to go down that road.
Warren
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Reply By: Nomadic Navara - Tuesday, Apr 17, 2012 at 17:44

Tuesday, Apr 17, 2012 at 17:44
Before you go any further read this article. After you do you will probably consider increasing the ball weight.

It's easy to calculate the change of ball weight by shifting the tank. First measure the distance of the coupling from the centre of the axles. Then measure the distance of the centre of the water tank from the axle group centre. Divide the second distance by the first distance. Multiply the weight of your water by that fraction and that is the weight on the ball caused by the water (add a couple of kilograms to the water to account for the tank.)

When you have done that you will be able to establish the ball weight without a water tank. You then can use similar simple calculations to find out your ball weigh with the tank in various positions. It's just simple 1st year high school physics application of levers.

I think you will have to shift the tank a fair distance to remove 30 kg from the ball weight. After the experience I have had with WDH I will not tow a van without it. Even with a stable van on the back the tug handles much better. In my early days towing with a 1992 model Hilux I towed my van 30 km without the WDH to a service agent, I made sure I took the bars with me for the return trip.

Also I don't think removing 20 - 30 kg from the ball will alter the handling of your rig by much.


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Follow Up By: Warren B - Tuesday, Apr 17, 2012 at 20:23

Tuesday, Apr 17, 2012 at 20:23
Hi peter, your right moving the tank back 1 metre will only lift 5kgs not worth the effort. So i guess i'll just have to use the WDH and get over it. not interested in the air bag thing. so now i'll move the battery back. just trying to make things simple but as someone before me said such is life.

Warren
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