Suspension Upgrade

If your suspension is still in good condition and your springs haven't already begun to sag you can just fit airbags in the rear to help bring the rear back up to the correct ride height when you're towing. The polyair bags in my ute lasted 9 yrs before one split recently which is a good run considering the weight they have carried.

Wouldn't putting larger diameter wheels and tyres on the caravan place more side to side leverage effect on the wheel bearings and stub axle ???

I should also add that I have towed my 16 ft, single axle van around Australia several time including through the centre as well as numerous dirt side roads and I have never had a tyre failure. That was with the van manufacturers recommended tyres and pressure (LT tyres)

That's confusing if the manufactures suspension is designed to handle the load which honestly it isn't so just say you put 5 people in the car and their gear in the back the rear will usually sag so your saying that some of their gear should be placed further forward to eliminate rear sag which you said wouldn't happen in the first place because the manufacturer has already allowed for this by fitting the correct suspension but most of us know they haven't. So then you have no choice but to upgrade the suspension at your own expense or fit a WDHT when towing to compensate for poor quality suspension which was only designed with comfort in mind and not load carrying ability like it should have been.. So you can't use the cargo area as it was designed just remember that manufactures all brag about how much cargo area they have but in the real world you can't use all of it so where are you going to put the gear on the bonnet or on the passengers laps. Also even if by some miracle you have your car loaded evenly your car will most probably ride like a boat down the road so suspension upgrades are quite often the safest and only option. I've had 5 wagons both leaf spring and coil and if you take a look most have a lot of rear overhang and none of them can safely carry what the manufacturer recommends without compromising the handling ability of the vehicle and that is why after market suspension is safer and has a massive place in the market. Discluding factory self leveling air bag suspension which is safer again.

Batt, we have have had this discussion before. A car will carry its full load without needing another company's suspension but it won't do it in every conceivable configuration that every owner wants. There are widely varying amounts of weight placed in each model car and it only becomes a problem when you start getting up near maximum. That is when weight distribution becomes critical if you want to avoid a sagging rear end.

If you load a car up to GVM and the rear is sagging then take it back to the dealer and ask why. If they haven't a clue then ask for a factory rep to call and see you. If you have loaded it correctly then it is their problem, not yours.

As for a WDH: If the car manufacturer says you must use one above a certain tow ball weight then it is part of the suspension design and must be used. They don't tell you to use one because they have fitted the car with a poor quality suspension.