Weight Distribution Bars

Submitted: Tuesday, Jun 21, 2005 at 09:46
ThreadID: 24043 Views:3530 Replies:7 FollowUps:2
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New to towing a caravan, if i have a tow vechile that is rated to 3.5 tonne with a tow ball rating of 350k ie " Nissan Patrol 4.8 " which has OME springs and shocks upgraded with a 3.5 tonne Kaymar rear bar do i need weight distibution hitgh like the hayman reese which has to come off for offroad travel, i expect the ball load to be around 280-300k or can i run with out one what benifit will the WD bring.
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Reply By: atoyot - Tuesday, Jun 21, 2005 at 10:46

Tuesday, Jun 21, 2005 at 10:46
When you put 280 - 300kg on the towball, the front of your Patrol will lift up, taking weight off the front axle and lightening the steering. This is regardless of how stiff the rear springs are. In fact, you could replace your rear springs with solid bars to stop the rear from sagging, but the front end will still lift up (I'm not suggesting that this is an option). Towing with a lot less weight on the front axle can be quite dangerous, as you simply don't have enough weight on the front wheels to steer effectively. This affects just about every aspect of towing, such as braking, stability etc.

Weight distribution bars are the ONLY way to distribute the weight load evenly between the front and rear axles. If you are going to be putting 280 - 300kg on the towball, then you should get a Hayman Reece 350kg weight distribution hitch. The 250 kg hitches won't be enough. It is also a good idea to measure the weight on the towball by visiting a weighbridge. I think another post may have had details about how to do this. They need to be setup correctly, but anyone who sells them should be able to help in advising on setup.

I found this out from experience towing a 2t van with a 100 series, and the difference was un-believable. I also used a HR hitch plate and chains so that the safety chains hitch near to where the towball is and this has the effect of shortening the chains so that if the thing jumped off the ball, the A frame would not hid the road. Usually, using the existing safety chain points on the towbar means that the chains are too long to keep the nose off the road. This plate also has it's own chains which can be used to secure the tow hitch to the towbar, just in case you loose a pin. I guess that it's just a bit more insurance in having a more secure hitch.

Hope this helps
AnswerID: 116667

Follow Up By: Member - Collyn R (WA) - Tuesday, Jun 21, 2005 at 11:03

Tuesday, Jun 21, 2005 at 11:03
Atoyot describes the situation very well.

Over the years I have found that many people simply do not grasp what happens when you place a heavy load on an overhanging hitch - and simply assume that this can be overcome by stiffening the rear suspension (which is worth doing anyway but does not in the slightest correct the lifting effect.

The effect is almost exactly like pushing down hard on the handles of a wheellbarrow. Do that and the front wheel lifts.

The problem is not so much counteracting the static weight as doing so when pitching - when the forces (and lifting effect) are very much greater.

There is only one question to answer re WDHs.

That is how much weight over the steering wheels, and hence steering ability, are you knowingly prepared to lose when cornering on an undulating slippery road with a strong crosswind?

If you want to know more about this - refer to my paper on Towing Stability on my website (click on 'Articles').
Collyn Rivers

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Reply By: Member - Ross P (NSW) - Tuesday, Jun 21, 2005 at 12:51

Tuesday, Jun 21, 2005 at 12:51
Onece you have towed with a WDH you won't go back. The number of times I've had to disconnect mine has been very very small.
AnswerID: 116699

Reply By: Member - DOZER- Tuesday, Jun 21, 2005 at 16:01

Tuesday, Jun 21, 2005 at 16:01
Gday
i once had to throw the anchor out the window whilst towing my van. In this instance it was backed up traffic around a corner on a highway.....lucky i wasnt going very fast, the front wheels locked up and i skidded for many metres, and this was with the load assisters on the back...they obviously werent doing enough..and less weight was on the front wheels than usual, but the cruiser had now become a 5 tonne load. Roughly 70% of braking is done by the front wheels of a car.....i suggest to you that it will be quite alright to tow your load around unassisted if nothing out of the ordinary happens....but who can guarantee that??
Be prepared, use the load distribution bars, and take them off when you get to the rough stuff, or tyou may bend your van axle.
Andrew
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AnswerID: 116741

Reply By: Steve - Tuesday, Jun 21, 2005 at 18:05

Tuesday, Jun 21, 2005 at 18:05
how do these Hayman Reese gadgets compare to ride bars?
AnswerID: 116756

Reply By: atoyot - Wednesday, Jun 22, 2005 at 10:50

Wednesday, Jun 22, 2005 at 10:50
If the bars you are talking about are the small solid bars with a sort of hook on the end, they do exactly the same thing as the HR bars, but on a smaller scale. For a smaller vehicle with a lower towbar weight, say a medium sedan with an 80kg towball weight, these bars (either 2 or 4 I think) will shift some of the weight back to the front axle. Using them on anything much above that sort of weight is a waste of time. The bottom line is that you are much better off spending the money in the first place, rather than either doing nothing or getting something such as those "helper" bars, for want of a better work.

I also agree, that if nothing ever goes wrong, you could get away with not using anything, but if you're going to tow on a public road, then little things go wrong all the time. Any situation such as swerving slightly to avoid a pot-hole can put the rig on a path to disaster with the pendulum effect that can develop from a slight sway.

I'd like a dollar for every rig I've seen that is not setup correctly, with the headlights pointing skyward; they really are an accident waiting to happen somewhere. So all we can do is try and get the message across. If everyone with a badly setup towing rig could just try a set of weight distribution hitches, they'd never go back to not using one. Also, bear in mind that I'm not talking about off road towing, just on the blacktop and dirt roads where trailer articulation is not an issue. I've actually got a 250kg hitch that I'm not using, but it would not be enough for 280 - 300kg,

regards

Andrew
AnswerID: 116862

Reply By: Member - Collyn R (WA) - Wednesday, Jun 22, 2005 at 17:45

Wednesday, Jun 22, 2005 at 17:45
Just a brief follow up.

Because of their very high inertia, long nose heavy 'vans generally feel ultra-stable. They lull their owners into a false sense of security - 'naah I don't need bars mate -she's as steady as a rock'. Until that day when a combination of circumstances starts it pitching and reinforces that movement.

I've studied many reports of accidents involving caravans without WDHs - almost without exception the owners say the rig had felt totally stable right up to the time of the accident.

People arguing against the need for WDHs are simply denying one of the more basic physical laws.
Collyn Rivers
AnswerID: 116929

Reply By: atoyot - Thursday, Jun 23, 2005 at 18:06

Thursday, Jun 23, 2005 at 18:06
Spot on, Collyn. I've seen some shocking setups; one of the worst, a Patrol ute with a longer tray and a 500mm extended towball hitch, and the little ride helper bars or whatever they're called.

The worst thing is that failure to rectify a weight imbalance situation only make the roads more dangerous for us all. Lots of people in the industry (towing and 4WD) don't seem to understand this principle either. I've even read tow tests in magazines that should know better, where they are basically saying that you can overcome rear end sag by fitting heavier springs. Come to think of it, they're right, but the problem is not really at the rear; it's at the steer end.

Sorry to sound like I'm on a soapbox, but I think the issue is important enough to feel the need to climb up sometimes. I hope 10Para doesn't feel like he's being lectured too much,

Andrew
AnswerID: 117103

Follow Up By: 10 Para (Qld) - Friday, Jun 24, 2005 at 20:10

Friday, Jun 24, 2005 at 20:10
Not at all Andrew, i am always one to take first hand advice thats why this site is such a great place when one is moving into a new area, and whears as i have lot of towing experince it has only been with Cmper Trailers which is whyu i am keen to get all the advice i can. We now have the van designed and it has come in at 21 ft just could not get it any smaller if we want to do any tough trips we will use the CT, i have managed to get the van really well balanced left to right with most of the heavey stuff ovet the tandam wheels, think i will achieve about 285-300 on the ball, had a van on the patrol a few days ago and it was about 2600k and onlt moved the back about 25m and still towed great the company that is going to build the van also advise the use of WD bars and looked over the Patrol this week and gave it the thumbs up still not sure about the size of the draw bar ie 100 or 150 as even my CT has a 150 on it.
Thanks for all your help
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