Thread: draw bar/chassis wall thickness

I would not use less than 3mm for the drawbar.

Also, for the size and carrying capacity, 3000Kg is an "in-between" rating for your axles. "Slimline" bearings (Falcon inner & outer) will give you 2800Kg. If you option "Parallel" bearings (Falcon inner bearing used as the outer as well), you get 3200Kg. The Coupling is 3500Kg rated, as is a 50mm towball. Ideally, you go the highest rating for the trailer, using the lowest rated item.

Thanks Yonnee,

Im thinking 3mm all around, just wondering if that would be an overkill especially considering your adding 40-50% more weight as a result. That coupled by the doubling of the chassis due to the tipper makes one heavy trailer.

In terms of the 3t rating, our local supply company has the parallel axles rated at 1500 each, so that will be the lightest of the whole setup. Its also the tow limit of the vehicle ill be using so it seems to be the best fit.

Parrallel axles are 1500Kg each if machined on 45mm square, and 1600Kg if machined on 50mm square. Seeing all the rest of the parts are the same, your axle supplier shouldn't be a great deal extra dollars to go the 50mm sq.
It doesn't matter that your tow vehicle only has a 3000Kg limit, you might update that vehicle in a few years, but you'll still have the trailer. For the extra couple of dollars now, it's almost impossible to uprate the trailer's registered ATM at a later date. Not trying to spend your money, but just giving food for thought.

The drawbar is the only part of the trailer that has the stresses it does (being held at both ends and bent in the middle). You could still go 2mm or 2.5 for the rest of the trailer. At 1.7Kg/M difference between 75x50x2.0 & 75x50x3.0, there will only be 10.2Kg in 2 x 3 metre drawbar rails.

Derr...
Let's try that again. There's only 2.1Kg/M difference between 100x50x2.0 and 100x50x3.0, so only 12Kg difference in the drawbar....

Thanks for your replies Yonee.
I have decided to go with 3mm all around on the word of a metal fabricator. His advice was not to go any less then 3mm, that way your guaranteed the strength. The build has begun.

Very interested in how you go and where you got or how you made up your plans as I wish to build one similar
Cheers rob

Some update pictures

Just wondering on the trailer build standards. This trailer is over 2.1m wide, so will i need white lights at the front? I was thinking of side clearance lights, two at the front on either side and another two at the back. If these stick out so that the amber is seen from the front, would this be sufficient?

Originally Posted by harmful81

Just wondering on the trailer build standards. This trailer is over 2.1m wide, so will i need white lights at the front? I was thinking of side clearance lights, two at the front on either side and another two at the back. If these stick out so that the amber is seen from the front, would this be sufficient?

The new changes to the reg's have made it extremely confusing as to how many lights are required for any given size.
Technically, you can only combine the front and side markers if the trailer is 2100mm or less.
If the trailer's less than 6000mm, then you only need one side marker, either at the front or rear. But you can option more.
However, one of the confusing points is the requirement for end outline markers, front and rear, as high as possible, for all trailers over 2100mm wide. I can understand additional lights for a Caravan or Horse Float or enclosed trailer over a certain height, but there's no height limit given, particularly if the trailer is low, like a flat top or box trailer or car carrier, there's no provision stated for combining with other groups of lights.

thanks for your reply yonnee,

I have reread the VSB-01 and there is two options under 13.8 for side clearance lights. the second option would only require clearance lights at the back. Still not sure on the white ones at the front, so i have emailed the WA branch of the transport department for clarification, hopefully they can shed some 'light' on it

Originally Posted by harmful81

thanks for your reply yonnee,

I have reread the VSB-01 and there is two options under 13.8 for side clearance lights. the second option would only require clearance lights at the back. Still not sure on the white ones at the front, so i have emailed the WA branch of the transport department for clarification, hopefully they can shed some 'light' on it

OK, I think I've got my head around this a little more, but there's quite a range of if's and but's, so I'll just concentrate on yours, being over 2100mm wide.

Front lamps:
2 x White lights facing the front.
You can only combine this light with a side marker when the trailer is under 2100mm wide.

"Either Option 1 or Option 2 must be met. Option 1 is based on an international standards arrangement (an option may be chosen even if it results in no side-marker lamps having to be fitted to a particular trailer)."

Side lamps, Option One:
Trailers under 6M long must have minimum one light on both sides, either in the front third, or the rear third. If at the front corner it can either be Red/Amber, or Amber only. If at the rear corner, it can either be Red/Amber or Amber only, or, if the rear taillight if it is visible from the side, this can suffice as the rear side marker.
You can have a light at both ends, but they must all be Red/Amber, or, Red at the back if using the taillight, and Amber at the front, or Amber at both ends.

Side lamps, Option Two:
Trailers under 7M long only require one pair of side lamps at the rear corner. This can either be Red/Amber or Red (if it's the taillight), or Amber as above.

Thanks for that info Yonnee.

From what your saying, i have no choice BUT to have the front white lights. I guess since the wiring is going past there it wouldn't hurt to put side clearance lights at the front corners then, and seeing as the rear lights will not be visible from the sides, i will need to put them on the rear corners as well. If i do this i guess Ive covered all bases.

It will still be interesting to see what the Department of Transport says in relation to this when they decide to get back to me, no doubt they will try and make it more confusing than it already is.

Originally Posted by harmful81

Thanks for that info Yonnee.

From what your saying, i have no choice BUT to have the front white lights.

Correct!
"For trailers 2100 mm wide or less, may be combined with 2 side-marker lamps that have been fitted, this being in accordance with Option 1 or Option 2."
Narrower than 2100mm, and you can eliminate the white, and have a Red/Amber on the front corner, but wider, they must be white.

I guess since the wiring is going past there it wouldn't hurt to put side clearance lights at the front corners then, and seeing as the rear lights will not be visible from the sides, i will need to put them on the rear corners as well. If i do this i guess I've covered all bases.

While they're not required, the reg's state that you can option as many additional side clearance lamps as you like, as long as they're evenly spaced. So your trailer will be covered if you put either the front two, or the rear two side lamps. But having them at both ends would be my preference.
As a fellow road user, I dont particularly like not being able to see a big trailer in the dark.
When I finally get around to build my own car carrying trailer, it will have one side lamp at the front corner, one at the front of the guard, one at the rear of the guard, and one at the rear corner.

It will still be interesting to see what the Department of Transport says in relation to this when they decide to get back to me, no doubt they will try and make it more confusing than it already is.

I too would be interested in their interpretation... if they themselves can get their head around it.
In my opinion, while some of the changes they made to the reg's made sense, others made it confusing and added too much "grey area" and open to interpretation depending on who's reading it.

well... the department of transport has been kind enough to respond to my online email query. The first email advised me to Refer to the Vehicle Standards Bulletin 1, which of course is what we are finding confusing. I told them that much, so they contacted their Technical section on my behalf, who referred me to a information bulletin link. http://www.transport.wa.gov.au/media..._VS_IB_129.pdf

I'm pretty sure that what Yonnee has suggested more than satisfies the criteria, so i will not be pursuing this matter with the transport department any further.