Sway control for light <span class="highlight">caravan</span>

thanks 671.

The suspension design is stock box trailer springs- 3 leaf. The only thing helping being the 71 inch axle.

I think you are talking about a sway bar as they called them in the 70's and I purchased one for my Valiant them days aftermarket that bolted straight onto the existing sway bar a the time to "stiffen" it all up so us young guys could corner faster.

It's obvious to me that sway and fishtailing are two different things. Sway is rocking from side to side and fishtailing is obviously movement that is quite different. Hence a sway bar would be more along the lines of fitting the need. Fitted correctly a sway bar wouldn't effect up and down suspension and one could be sort from a wrecker.

Thanks for the tip. Hadnt thought of that.

Tony

Tony

I am not talking about sway bars. Have a look at your trailer springs then compare them to a car with leaf springs. The trailer will have a short spring with a fair size arc in them. The shackles will be at the same height.

A car will have a much longer and flatter spring. The front spring eye will be mounted much lower than the rear eye. The axle will be placed further to the front end of the spring than the rear end. When the car is nearing full load, the front section of the spring will be either parallel to the ground or sloping up to the axle. As the car leans into a corner, the spring will go into a concave shape and the axle will get closer to the chassis. This swings it up in an arc around the front shackle bolt and takes the wheel closer to the front of the car. The wheel on the other side will be dropping down and moving back. The axle will now be pointing slightly in the same direction as the front wheels. That is roll understeer. It assists in vehicle stability and is the reason why car and ute leaf springs are made long and fairly flat and mounted with the front lower than the rear.

They don't go flat when loaded and concave in corners because the car manufacturer does not know how to make a good suspension like many people with overloaded rear end sagging cars seem to think. They have been designed that way.

Now go back to your trailer suspension and you will soon see that it can not possibly give the same result. In order to pull the outside wheel slightly forward in a corner, the axle has to get up higher than the front mounting point for the spring. That is impossible with a flat chassis. All the spring can do is flatten slightly and push the wheel back. The other side will drop down and pull its wheel forward. You now have the axle pointing in the opposite direction to the front wheels and that is not real good.

Fishtailing and swaying (yaw or leaning) go together. Have you ever seen a fishtailing caravan remaining perfectly upright while it swings from side to side?

I don't know how your little van is going to behave but if it does get knocked about by high wind or passing trucks then it is going to move to one side and lean over then whip back and maybe go too far the other way. That is when a car like suspension design could be a priceless advantage.

Thanks for that. Such clarification.

Certainly I'm now armed with really good information once the van is on the road.

I've even printed this thread out.
Tony

G'day, exactly why my camper trailer with Hilux rear springs tracks so well.................