AnswerID: 356612 Submitted: Friday, Mar 27, 2009 at 16:24
Tenpounder
replied:
Hi. Graham H from Qld raises an interesting point. We're used to the 10% rule for towball weight in Oz. But the design of this van is for a towball weight between 65 and 100 kg (ie between 4% and 6% of ATM). I don't know why the van manufacturer does not want the owner to put more than 100kg (perhaps we shouldn't ask!) on the drawbar.
So either we're old fashioned, and the 10% rule is out of date, and modern engineering has overcome the old stability problems, or else we're facing an onslaught of unstable rigs whose owners can proudly show all weights in spec - in this case, the van at 1600 kg, 4% on the drawbar; the Pug with a load with specs and with the ball weight held to 68kg.
I don't think the 10% rule has any legal standing, but I could be wrong.
I for one feel a need for an engineering explanation of th stability of a rig with 4% nominally on the towball (hit a bump; back of the car goes up, flicks the drawbar up with it; what's the drawbar weight now???)
It really is an issue that needs to be resolved.
Chris (SA)
Reply 8 of 8