Building a heavy duty trailer and have some planning Qs?

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Rogers Cruiser
Part of the furniture
Posts: 1327
Joined: January 3rd, 2014, 8:04 pm

Building a heavy duty trailer and have some planning Qs?

Unread post by Rogers Cruiser » June 24th, 2014, 7:37 pm

Hi all,

Im going to build a heavy, single axle box trailer for some 4x4 applications. And I have some questions regarding the plans.

Does anybody know what the weight restrictions are for a single axle?

Or length for a single axle trailer?

Or to save time does anybody have a copy of the RTA (NSW) guide to home built trailers or whateva its called. I had a hard copy years ago but i cant find it!

Thanks.
'98-'06 - FJ-45 Ute fell over one day and didnt survive
'06-now - HJ-47 Troopy, restored and now daily driver.
'13-now - HJ-47 Ute, Farm fresh rust bucket, needs a restoration. viewtopic.php?f=22&t=152811

now - Off Road Box/Camper Trailer. viewtopic.php?f=134&t=153968&p=1792444#p1792444

Dont listen to me, Ive got an opinion on everything!

hotgemini
Here and there
Posts: 67
Joined: December 15th, 2008, 3:41 pm

Re: Building a heavy duty trailer and have some planning Qs?

Unread post by hotgemini » June 29th, 2014, 10:21 am

So, the bible for all of this is "Vehicle Standards Bulletin 1 - National Code of Practice - Building Small Trailers" ('"VSB1") published by the Department of Infrastructure, Transport, Regional Development and Local Government.

You can view it online and download a PDF copy of it here http://www.infrastructure.gov.au/roads/ ... etin/vsb1/

Strictly speaking, the only limit on what you can do on a single axle under VSB1 is that it only covers trailers up to 4.5t aggregate trailer mass ("ATM"). In practice, if you're looking to use typical light trailer components, then you'll be limited by those first.

Your gross trailer mass ("GTM") on a single axle trailer will be limited to the lowest of the ratings on your:
Tyres
Rims
Axles
Suspension

Once you go over 750kg ATM you'll be required to fit 'efficient' brakes.

Once you go over 2000kg ATM you're no longer permitted to run over-run brakes and you must have a brake-away system which will apply the brakes for 15 minutes in case of the trailer becoming disconnected,

From the 1st of July 2014 (eg. this coming tuesday), once you go over 3500kg ATM you will be required to either:
* Fit ABS
* Fit a load proportioning brake system
* Demonstrate that the trailer meets the unladen braken performance requirements without a load proportioning brake system

Maximum length is 12.5 metres (assuming you're setting this up as a pig trailer, not as a semi-trailer).

Hope this helps.

-Adam.

Rogers Cruiser
Part of the furniture
Posts: 1327
Joined: January 3rd, 2014, 8:04 pm

Re: Building a heavy duty trailer and have some planning Qs?

Unread post by Rogers Cruiser » June 29th, 2014, 11:24 am

gemini, thanks that is exactly what I was looking for. !
'98-'06 - FJ-45 Ute fell over one day and didnt survive
'06-now - HJ-47 Troopy, restored and now daily driver.
'13-now - HJ-47 Ute, Farm fresh rust bucket, needs a restoration. viewtopic.php?f=22&t=152811

now - Off Road Box/Camper Trailer. viewtopic.php?f=134&t=153968&p=1792444#p1792444

Dont listen to me, Ive got an opinion on everything!

axialmark
Here and there
Posts: 22
Joined: May 20th, 2014, 10:14 am

Re: Building a heavy duty trailer and have some planning Qs?

Unread post by axialmark » July 9th, 2014, 1:31 pm

Roger
One thing if you haven't picked it up from the RMS site is that in NSW if the trailer is over 350kg unladen it will require annual rego check.
I built a trailer a few years back to match my Ford RTV ute using a BA tub with RTV flares and wheels.
A couple of things to consider during planning
Select the rim you want to use ( if different to tow vehicle ) and order your axle with the hub to hub measurement required to have trailer track width match tow vehicle it should not cost any extra $ and particularly if going off road it is much better to have trailer wheels follow your cars wheel tracks.

Figure out what height you want trailer to sit in relation to your car and work your spring hangers around that ( I set up my trailer so that the ute and trailer tubs were level when the trailer was loaded with camping gear )

If you have a ute or wagon with drop down tailgate try to set the tow ball height on your bar so that the tailgate doesn't hit the hitch when you lower it and then match the draw bar height to this with the trailer sitting at desired angle (level)

On my trailer my draw bar is separate to chassis and is welded to the drop box for front spring eyes and also the front cross member of the chassis.

This may sound like a no brainer but there is nothing worse than not being able to lower your tailgate with the trailer hooked up and if you have a Hayman Reese style receiver hitch you have a massive choice of tongue height's to select from to suit your application.

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