Weight distribution
In the world of towing there are a few safety items that everyone should be aware of before venturing out on the road. Besides the obvious such as registration and roadworthy certificates for both vehicle and towed load some other major safety concerns are :
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Tyre pressures on both vehicles
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Even distribution of loads
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Towball weight
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Vehicle GCM (Gross combined mass)
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Trailer / Caravan ATM
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Vehicle and Caravan GVM (Gross vehicle mass)
In relation to what this article is about we will be focusing on the use of Weight distribution hitches (WDH) specifically the Andersen WDH to distribute the load between a Caravan and vehicle.
Before even considering if you need a WDH you need to do some weighing and some measuring to be self satisfied you need to spend anywhere from $300 -$700 for a Hayman reese WDH to $900 - $1000 on a Andersen WDH.
What we are trying to avoid
Having too much weight from a trailer or caravan on your tow-ball makes the front of the vehicle lift as per above photos. This in turn will reduce steering and braking on the front of the vehicle but will also overload rear suspension and chassis components of the tow vehicle, as for the caravan/ Trailer to much load at the back of the caravan and not enough at the front will cause the trailer to sway during travel which can lead to accidents. There is a fine line to getting it right so as mentioned weighing and measuring is well worth the effort as Guesstimating or using eyeometer is no where near as accurate when yours or someone else's life is at stake.
Advisable steps to take
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Your first task is to look up your handbooks ( or the identification plates) for the vehicle and caravan to see what the maximum load is your caravan and vehicle can carry. For your van this is your ATM (Aggregate trailer mass) and includes everything your going to have in the van when travelling... water, food, beer etc. For the car it's called GVM ( Gross vehicle mass) and is same principle, includes driver, passengers, fuel etc. ( IE: fully loaded) Record on paper the allowable weights based on your handbook "Car GVM" "Caravan ATM"
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Load up both vehicles as per #1
- Pick up a tow-ball weight scale from tow safe or your local Super-cheap
- Place tow-ball scale under the draw-bar coupling of your van and lower the jockey wheel down so the scales take all the weight. record this weight on paper as "tow-ball weight". Check in your vehicle handbook for maximum allowable tow-ball weight and record that as "Tow-ball max"
- If your tow-ball weight exceeds tow-ball max then you need to shuffle items around in your Caravan to re distribute the weight evenly. Recommendation is %10 of Van ATM on your tow-ball.
- Now that the tow-ball weight is within limits after re distributing the loads, Go to your vehicle while on flat ground and measure the height from centre of front wheel to the start of the wheel arch ( in the 12 o'clock position). Record that as front suspension no load do the same for the rear and record that as Rear suspension no load.
- Making sure Caravan is also on flat ground back the vehicle up and reconnect the van.
- Re measure front and rear suspension heights now that the weight of the van is on the towball and record as front suspension loaded and Rear suspension loaded. If rear suspension loaded dropped more then 20mm of the rear suspension no load reading then you should consider a WDH, likewise if front suspension no load is less than front suspension loaded consider a WDH.
If you've performed the above and comfortable the vans not going to break in half then find your local weighbridge and get both car and van weighed independently, record those readings as Actual Car GVM and Actual Van ATM.
Legally and for safety reasons you must not exceed the recommended GVM, if you do you will have to remove un necessary items that contribute to the weight. You will have to re check tow-ball weights and suspension measurements any time you change the load of any significance.
Combine both Actual Car GVM and Actual Van ATM to get the GCM (Gross combined mass) which should not exceed the manufacturers recommendation in your vehicle handbook.
So do you need a weight Distribution Hitch?
By having a WDH installed, the weight that is normally transferred to the rear suspension (which takes the load off the front suspension) is once again transferred back to the front suspension making it safer to steer and brake and drive. However, having a WDH does NOT mean you can overload the van or the towball and counteract it with a WDH.
For years most people have been using Hayman Reese WDH or similar brands and they work fine i'm sure but they do come with disadvantages such as
1. noisy when driving
2. they don't assist in sway control unless you buy the addon parts
3. you need to remove it when backing in sharper turns
4. there is tension bars you need to lock and release which apparently hurts when you slip doing it.
Around 2011 a USA company developed a new style of WDH called the Andersen WDH. Now i don't work for them or get commission from them but i don't mind endorsing the product as that's what i use and find it brilliant.
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The Andersen weight distribution hitch is a good design in my opinion as it has these advantages over the earlier style.
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Not noisy
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No need to remove when backing
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Built in Sway control
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Light weight compared to others
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Noticeably reduces trailer bounce as you go over un even roads
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Easy to disconnect and reconnect
Disadvantages
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Costs more than earlier style WDH
Overall i'm happy with the performance of it and highly recommend that the " SHE'LL be right mate" attitude not be adopted when it comes to safety issues such as weight distribution. Me being me i'd like to go into a explanation of how the Anderson hitch works but that would be like re inventing the wheel so please check out the links below for further info.
For links to more info see below
