Increase max towball weight

Submitted: Friday, Jun 11, 2004 at 04:54
ThreadID: 13679 Views:4402 Replies:5 FollowUps:2
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Vicroads have told me I can legally increase my maximum towball weight. All I need is an engineers report stating that the stability of the vehicle(2003 Mitsu Triton) will not be compromised and also that allowances be made with regard to the rear axle load. Too easy, right? Can anyone recommend an engineer as I can't find one locally. I have been to caravan, trailer and towbar manufacturers; but if it's not their product they are unwilling to help. ARB dropped me like a hot potato when I aproached them, even though it is an ARB hitch...

Any help appreciated
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Reply By: Wayne (NSW) - Friday, Jun 11, 2004 at 06:59

Friday, Jun 11, 2004 at 06:59
I would have thought that it would be the vehicle that whould be limiting factor in the ball weight. If dual wheels were to be fitted to the back of your ute then you might have a case bur apart from that I can not see how the back of your vehicle can take tha extra weight. If the springs were beefed up that would only mean that the back would not sag as much, it does not mean that the vehicle can carry more weight. The other thing that would have to be looked at is stopping the vehicle. If more ball weight means towing more weight than the brakes would have to be looked at. Extra weight on the back would also mean the steering and braking on the front wheels would also be effected.

AnswerID: 62749

Reply By: Member - Pesty (SA) - Friday, Jun 11, 2004 at 08:44

Friday, Jun 11, 2004 at 08:44
The very moment an engineer puts his name to anything like that he becomes liable if something goes wrong, and you are the user which he has no control over, mitsubishi engineers are the only ones that could do that and they have already done it, its on the compliance plate, so you wont find one.
AnswerID: 62757

Reply By: The Banjo - Friday, Jun 11, 2004 at 08:56

Friday, Jun 11, 2004 at 08:56
If you get onto Cameron Caravans SA (08 8276 5444) they can put you onto a bloke named Tom Olthoff - he's a consultant and trainer in all matters towing.
Tom may be able to connect you with an engineer in this game in Vic....he's very much into the caravan industry.
AnswerID: 62761

Reply By: Andrew - Friday, Jun 11, 2004 at 13:59

Friday, Jun 11, 2004 at 13:59
Hello Blue

Not sure if I completely understand what you want to do, however the following may help.

The towing capacity of a vehicle is set by the vehicle manufacturer. The capacity of the towbar is set by the towbar manufacturer and has to be stated on the bar.
If the bar is rated differently to the vehicle then you go with the lower figure.

The vertical weight allowed on the towball for towing is usually between 5 & 10% of the trailer weight. Outside this range you are normally into load levelling systems etc.

The towbar itself is manufactured to take up to half its rating on the towball, however this is a strength requirement, not a figure you would use for towing. This is to take into account the strength of the vehicle attachment and structure as well as the bar strength. It also allows for the dynamic loadings which the bar designer has to take into account.

If you want to increase the towing capacity of the vehicle then an engineer will usually have to upgrade your suspension system and vehicle structure to allow it to be re-rated. This can affect axles, wheels, tyres, springs and mounts and require subframes or other structural modifications.

VicRoads can send you a list of recognised engineers if you fax a request to them on Fax 9854 2668


AnswerID: 62790

Follow Up By: Bluegeorge - Friday, Jun 11, 2004 at 16:12

Friday, Jun 11, 2004 at 16:12
good to get a solid response... This all started when we were given a caravan and it's towball weight (145kg) exceeded that of the triton (100kg). I am aiming for a situation like the Navara. Nissan allow you to increase your towball weight up to around 240kg as long as you reduce your actuall vehicle load accordingly.

How do you calculate the effect of load levelling devices? Do they actually reduce the towball weight?

Will contact Tom from SA and see what he has to say.

Thanks guy's
FollowupID: 324076

Reply By: itldoo - Thursday, Jun 17, 2004 at 23:42

Thursday, Jun 17, 2004 at 23:42
With my experiences with tow bars, you can't increase the pulling weight of the tow bar. Hayman Reece fabricate the tow bars to the pulling capacity of the vehicle. But you can increase the ball weight with their weight distribution hitches.You want to tow more than the tow bar is rated too. Buy a bigger vehicle.
AnswerID: 63683

Follow Up By: Bluegeorge - Friday, Jun 18, 2004 at 19:41

Friday, Jun 18, 2004 at 19:41
G'day itldoo

I don't need to tow more, I just need an extra 50kg of down force on the tow ball taking it from 100kg to 150 kg. This is to cover the van I inherited after I'd already bought the vehicle. I figured after seeing a mate get away with 4" body lift, 4" suspension lift and replacing the cruisers split rims with sunnies carrying 35" BFG's, how difficult could it be to fullfill my request... It seems adding the 50kg to a towball is far more likely to produce a legal stouch than the previously mentioned Tojo.

If I ever find the answer I'll post it, thanks for the input.

FollowupID: 324955

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