Monday, Apr 24, 2017 at 21:13
It is not easy to put a slide on camper onto a dual cab without overloading the rear end. If I was to try doing that the first thing I would do is remove the tray and have a camper custom built that bolts directly to the chassis. It would be as light as possible and contain only the features I consider to be absolutely essential. All heavy items would be as far forward as possible.
Most professionally built campers are designed to cater for as wide a range of buyers as possible resulting in them having every conceivable feature and a weight that is through the roof.
The big problem with a dual cab is weight distribution. Get it wrong and the chassis is at risk as the others have already pointed out. The main reason for incorrect weight distribution is they are a five
seat car and very few people have enough weight in those seats when they load the car up near its maximum.
There is no point in the manufacturer designing the car to carry no more than the weight of an average weight mum and dad with three primary school age children then five rugby forwards or five large tradesmen get into it. The cabin must be designed to carry the weight of five large adults and all the things like winter clothing, brief cases, books, camera bags, water bottles etc. that people put in the front with them. That means close to 500 kg up front before you start loading the rear if you want to fully load the car.
If you can't do that then you can't fully load it without overloading the rear end.
The chassis bending problem comes from leverage. The distance between the rear axle and the end of the tray is a lever. The further back you put each item, the more the leverage on the end of the chassis. If you push the end of the car down,
the springs compress but the whole car tilts on the rear axle and the front goes up. If you install heavier springs or air bags, the car still tilts on the axle and the front still goes up.
That is what weight will do but the real killer is mass and the forces it generates when put into motion. Mass is the amount of material in something.
When you put a loaded slide on onto the tray, the back will go down a certain amount and the front will lift a little. Now imagine lifting the slide on about 200 mm above the tray and dropping it. It will hit with a hell of an impact that thumps the back down and throws the front up.
Its weight has not changed but the material in it has fallen, built up momentum, and has been brought to a sudden stop by the end of the car.
I have never heard of a chassis bending while the car is stationery but it all changes when the car moves. As wheels rise and fall, sometimes rapidly, in accordance with the road surface, whatever material is behind the rear axle is constantly being heaved up instantly or caught when it falls.
That is what bends chassis, particularly in off road conditions, and heavier springs, GVM upgrades or air bags can not stop it.
Here is a few bent chassis photos.
BENT PHOTOS
One more point to consider is the off road carrying and towing capacity. The maximums specified are usually for good sealed roads only and should be reduced as conditions deteriorate. There are far too many variables for manufacturers to attempt to list loads for all conditions but they will usually advise you if you ask.
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