Trailer Design

[Dean Stephens]

Hi Guys,

Please can someone tell me if there is a scientific method to determine the length of the A-frame/drawbar of a trailer (for example is there a specific ration between width/length of the loadbox and the length of the A-frame) or do you just construct the drawbar to be the most practical for your application?

[Jakes]

There must be a spec on this, I' will try to get hold of a local trailer shop and find out what the spec is.

[Org M]

My logic tells me that if you want to do it scientifically, it will have to be based on your/a specific vehicles width, turning circle and vehicle axle positioning.
I am looking at doing an adjustable draw bar, where the coupling section is. This will allow you to lengthen or shorten the draw bar length if required.
See link of quite an interesting build.
http://www.davebence.co.uk/trailer_project.htm

[albie]

Hi Dean,
I found this link through Google.

https://www.sabs.co.za/content/uploads/files/VC8026.pdf

Regards

Albie.

[Dean Stephens]

Albie,

Yup, I did have a copy of that Spec in the gazette (thanks for taking the trouble to Google it and post it, much appreciated)and although it does address the question of Articulation Angle it does not tell me if there is a "correct" way to design the drawbar length. I have spent some time crawling around the local trailer sales and hire shops with my tape and basic protractor and what seems to be the design criteria is “do what works for your application using just a little common sence”
Regards….