A while back I seem to recall that someone asked if the towing capacity was affected by inverting the towbar shank? (Tongue). Finally I have found the picture that I was looking for at that time.This may be of interest to those of us who tow big heavy vans with Toyotas,as using the tongue incorrectly could compromise an insurance payout in the event of a claim being lodged.Cheers
you still have a ball weight of 350 kg and as you have pointed out enough times a 200 series can not tow 3500 legally so for a 200 series it makes no difference
you still have a ball weight of 350 kg and as you have pointed out enough times a 200 series can not tow 3500 legally so for a 200 series it makes no difference
Thanks Gary,for pointing out that the 200 series cannot safely tow more than 3000kg ATM as a PIG trailer,and would not need a TBM of more than 300kg,but I simply was following up on a previous post where I was unable to locate the provided information.Cheers.
The engineers amongst us could tell us why the difference- something to do with the downward pulling effect of the two angles.
As there is no differential in friction to consider, you therefore consider turning force, on a straight pull (force). You find differential displacements by calculating the distance between an objects initial position and its final position. These calculation should be done on both towball shank positions.
Safe working loads are usually calculated by dividing multiple actual test breaking force by a safety factor of 3 or 5.
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Possum; AKA:- Ali El-Aziz Mohamed Gundawiathan
Sent from my imperial66 typewriter using carrier pigeon, message sticks and smoke signals.
To add to the above I had reason to buy another tow bar tongue to correct the height of a boat that I had a need to tow and I bought the tongue from a reputable tow bar supplier. The tongue was actually bolted to the shank to enable slight adjustments and that tongue assembly was rated at 3500 kg wether used to raise or to lower the drawbar height. I did not need the rating to be that high but that is just how it came. I would also be wary of any part of a towing attachment that was supplied by any of those large cheap parts places as they will be more than likely made in China and may not comply.
Regards
Rob
-- Edited by bentaxlebabe on Monday 21st of December 2020 09:37:34 AM
It seems that the Prado and LC200 additionally have differing sized throats for tongues as well - My Patrol tongue will fit Mate's 200 but not Son's Prado.
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Possum; AKA:- Ali El-Aziz Mohamed Gundawiathan
Sent from my imperial66 typewriter using carrier pigeon, message sticks and smoke signals.
It seems that the Prado and LC200 additionally have differing sized throats for tongues as well - My Patrol tongue will fit Mate's 200 but not Son's Prado.
That is a good point as well.
The Prado has a lower towing capacity as far as I know so they possibly made the shank smaller to maybe save some weight.
The reason for the difference is more than likely because of the load path.
If you look at the higher rated diagram, the ball is almost on the centre line of the tongue so the load path in tension is almost a straight line, whereas the lesser one, the ball is well above the tongue centre line, so the load path is not straight. This will cause a drop in safe load capacity due to the additional moment being applied to the tongue.
The reason for the difference is more than likely because of the load path. If you look at the higher rated diagram, the ball is almost on the centre line of the tongue so the load path in tension is almost a straight line, whereas the lesser one, the ball is well above the tongue centre line, so the load path is not straight. This will cause a drop in safe load capacity due to the additional moment being applied to the tongue.
Great analysis Greg...I hadn't even considered that,but it is so simple,isn't it? Well done! Cheers
