trailer for truck

Hi all,

Currently we looking at our options wrt a flat bed trailer to tow behind the truck.
Doing the sums as to building it ourselves, possibly utilising this tray thats sitting in the yard. Of course if something suitable secondhand came up in the meantime would definetely look at it. Buying one new looks to be an rather expensive excercise, so wont be going down that road.

Recon 1.5 tonne max for actual trailer with 3t payload, to equal 4.5 tonne gross trailer mass would fit the bill nicely.
That should keep things within VSB-1 if I read the writing corretly. Also I hear the rego jumps up as well if one exeeds this, but havent confirmed this yet.

Looking at the specs a 70 mm ball would be the minimum required.
Current thinking is tandem setup with 65 mm round axles and cruiser stubs.
12 inch Electric brakes on all 4 with breakaway setup.

So spending a bit of time at present looking at stuff that already made, as in drawbar/sub frame sizing. Leaning towards 125 x 75 x 4 mm for the drawbar, however am definetely open to suggestions.

As for flooring dont recon we will go for full checkerplate, just a couple of wide strips running full length to line up with the tractor. Along each side would run a narrower piece.

Considering extending the tray a bit with a banana back so could get away with running shorter ramps.

So Yeah there is still a lot of research that still needs to be done.

I do know 1 thing about trucks that tow trailers...they shake the cr*p out of the drawbar of the trailer...so this needs to be very well designed etc.

I have also seen some hitches on trucks that have suspension built into them to try and eliminate this.

Post up pics as you go as I'd like to see how it pans out

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trucks that tow trailers...they shake the cr*p out of the drawbar of the trailer

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Yeah certainally not rushing into this and will be studying a lot of trailers and picking many brains before going any further.

Will be looking closely at things like axle placement. I know from experience that I would rather be towing a tandem, especially when there is fair amount of weight involved or long load. Seems to be a lot less rocking motion than a single axle. Of course good load placement never goes astray.

Rego in Vic is the same for all trailer up to 4500Kg. After this, it jumps into the semi-trailer territory and get charged at $550.00 per axle!
Have a look into Bartlett ball hitches. They're rated much heavier than a standard trailer coupling (and priced accordingly), but even though you only rate the trailer and register it at 4500Kg, there's nothing stopping you having higher capacity components on it.

Yeah I was talking to a bloke a while back who runs earthmoving equip wrt rego, he was saying similar things about the whole axle charge thing. Part of the reason why I wanna stick to no more than 4.5 ton.

Had a quick look at Bartlett ball a few weeks ago. For interests sake I see they come in 95 and 127 mm. From a quick look at their specs the 95 has a 7 ton rating. Have been turned off the ring pull from my AJ days, even the Rovers had them.

The one thing with a Ring type coupling, is that you can get a pintle hook that also has a 50mm ball, which allows you to tow an ordinary trailer as well as your heavier one. However, they're a bit unsettling with all that clunking felt through the towbar.
Even though the smallest Bartlett is 7Tonne, you only rate the trailer on its VIN plate at the weakest link.

As for the axles, see Melbourne Trailers or Al-Ko about their standard 3Tonne rated axles. This size is the next step up from 2Tonne axles unless you look at Melbourne Trailers 2.5Tonne Dexter axle. It runs the standard 12" Electric Brake, but a fairly unique Yank bearing set for the Dexter axle stub.

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they're a bit unsettling with all that clunking felt through the towbar

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Yeah my experience is pretty much what you describe. I really got turned off when it came to backing, even the smallest of trailers in the Army had this ring coupling.

Dexter axles - would bearings be off the shelf item? U know if I needed replacements. We have a few bearing stockists up here, but not much wrt trailer joints. Gotta think of this crap when u live miles away.

On the subject of hitches. As Yonee said pintles do have the ability to tow both ring and standard 50mm ball couplings if you choose the correct unit.
There is a coupling - 70mm I believe, that is an upscaled version of the standard 50mm ball. From memory it is rated at 4.5T and is quicker and more convenient to couple than the Bartlett setup.
My personal favourite of all couplings is the ringfeeder, (at its best with dog trailers admittedly), set the coupling, reverse in, hear the pin click home, drive forward to do a tug test, hop out check the safety lock, hook up lights, air and chains if need be and you're done.
Your target weight of 4.5T precludes a 50mm ball as you no doubt realise, but it would be good to still service this tpye of coupling, so maybe the pintle hook is your best option or perhaps an upscaled version of a Hayman Reese receiver that would allow you to swap hitches.
What sort of drawbar does your truck have? Drawbars are now a lot more tightly controlled than they once were and can be quite an expensive item in the higher ratings, ie, over 3.5T. Just something to add to your research list.
One other thought. Is your truck 12 or 24 volt? Most Brake controllers I have seen were 12V so you may need to consider a voiltage reducer for the lights, (yes you could run LED or 24V globes, but if you hook on someone elses trailer the results will be both bright and brief), as well as the brakes.
If I read this correctly and you wish to use this trailer only for carting tractors etc. than I think I would start from scratch rather than try to use the old tray.

Whatever you do, make sure that the drawbar, coupling and chains are adequate. We had an accident in Tassie last wednesday where a trailer came off a truck and struck a patient transport vehicle headed in the opposite direction. Attachment 232898 The result 3 dead and 7 critically injured. From what I can decipher from the photos, it appears to me that the coupling failed, (I can see the bolts still in the drawbar, but no coupling on them), secondly the safety chain either was not connected or failed - how many times do we see a rated chain attached with a mild steel shackle. The drawbar failed only when already detached from the truck. I believe that the trailer, a tandem, would have most probably been under the weight limit for breakaway brakes. One thing I am glad of - that I did not build or maintain that trailer.

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Originally Posted by Karl Robbers

Whatever you do, make sure that the drawbar, coupling and chains are adequate. We had an accident in Tassie last wednesday where a trailer came off a truck and struck a patient transport vehicle headed in the opposite direction. Attachment 232898 The result 3 dead and 7 critically injured. From what I can decipher from the photos, it appears to me that the coupling failed, (I can see the bolts still in the drawbar, but no coupling on them), secondly the safety chain either was not connected or failed - how many times do we see a rated chain attached with a mild steel shackle. The drawbar failed only when already detached from the truck. I believe that the trailer, a tandem, would have most probably been under the weight limit for breakaway brakes. One thing I am glad of - that I did not build or maintain that trailer.

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Ouch!!
I wonder though, whether it may have been a weld accross the top of the drawbar that has caused the drawbar to crack and eventually fail. You can clearly see in the photo that the drawbar has become detatched at that point. Being the driver's side that let go would have speared the trailer off in that direction while still attached to the tow vehicle via the coupling and the left hand side of the drawbar. As the trailer veered over, the front corner would have been in the path of the oncoming van (as seen by the bent side tailgate on the trailer, and the damage to the driver's side of the van rather than a front-on impact). The trailer would have peeled the open the van like a knife through a cardboard box, with catastrophic results. The resultant impact would then have been what tore the coupling from the drawbar. (I'm guessing the Bass Hwy would be 100k/mh zone, so a 180km/h+ impact...)
http://resources3.news.com.au/images...ie-tragedy.jpg


The bend in the road might not have helped if the van had drifted slightly towards the centre of the road, or the towvehicle starting to cut the corner...

That's a possibility Yonnee. The Bass Highway at that point is actually 110KMH so the impact could potentially have been around 210KMH.
I did notice that the bends in the gooseneck section of the drawbar were not reinforced in any way. Can't say I'm a big fan of goosenecks unless a lot of thought and design goes into them.
I will be very interested to find out exactly did go wrong.
It makes you wonder just what is coming towards you when on the road and I think back to some of the trailers that I have repaired over the years where well meaning handymen had welded across drawbars or had more slag then metal in the welds etc.
I can see the day coming where home built trailers will be a thing of the past. It is already here to some degree - you are no longer allowed to fabricate towbars without engineer certification yet you can build a trailer with comparatively few checks and balances other than a cursory inspection by somebody that often has no idea. I towed a trailer, (tandem box, 16" rims, overide brakes on 4 wheels, around 3.5X1.8M newly registered) recently. I thought this is a pretty neat looking trailer. UNTIL - I walked around to the side of the trailer and found the axles around 200mm forward of center! I later spoke to the owner and he said "I dunno what's wrong, the thing's a dog, gunna sell it. Wouldn't you love to tow that thing at 100K's with a load on. I actually wonder whether they welded the drawbar under the wrong end, (of course that would mean that the springs would also be back to front).
If I do find out what went wrong I will be sure to post it on the forum. I reckon that the story will take some time to surface - coronial inquests etc.
Imagine how the driver of the truck must feel plus the legal implications he may be facing.

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Originally Posted by Karl Robbers

If I do find out what went wrong I will be sure to post it on the forum. I reckon that the story will take some time to surface - coronial inquests etc.
Imagine how the driver of the truck must feel plus the legal implications he may be facing.

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Well, for anyone that is interested, I have done a little digging and this is the story so far.
The trailer was borrowed, not designed for the tow vehicle and the drawbar height was totally wrong for the tow vehicle. As an addition to the list of wrongs, the safety chains were not connected. The drawbar failed after impact.
It would not surprise me if the coupling was subjected to a lot of upward force, (remember incorrect drawbar setup) and the 50mm ball coupling suffered a failure in the locking pin, (I've seen these fail before), which was then unrestrained by the unconnected safety chains, thus leading to a 100KMH uncontrolled missile that unfortunately found a soft target.
If I hear more I will fill you all in.

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Originally Posted by Karl Robbers

Well, for anyone that is interested, I have done a little digging and this is the story so far.
The trailer was borrowed, not designed for the tow vehicle and the drawbar height was totally wrong for the tow vehicle. As an addition to the list of wrongs, the safety chains were not connected. The drawbar failed after impact.
It would not surprise me if the coupling was subjected to a lot of upward force, (remember incorrect drawbar setup) and the 50mm ball coupling suffered a failure in the locking pin, (I've seen these fail before), which was then unrestrained by the unconnected safety chains, thus leading to a 100KMH uncontrolled missile that unfortunately found a soft target.
If I hear more I will fill you all in.

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Just a follow up to this.
This matter has now been through the courts and the driver of the truck has been convicted and sentenced to 3 1/2 years jail with 2 1/2 years suspended, subject to appeal at present. The driver was charged and convicted based upon his failure to attach the safety chains, but no mention was made of the coupling failure, (I positively know the coupling failed through an acquaintance who was directly involved with the accident scene). Perhaps this is yet to come.
This all goes to show what a serious business trailers can be.

Thanks for keeping us updated. It is such a sad thing to have happened but hopefully this is a big wakeup call to anyone getting complacent with towing trailers

Yep its an oldie, but this pickup is showing promise.Normally would have run for the hills, but as soon as I saw how heavy the steel is on this thing, well it followed me home on the back of the truck. For $400 bucks (including fuel to get er home). Worst case I will cut er up for material for shop projects!!! A gentle touch with the grinder reveals that the rusty bit behind the guards is just surface. Think it was a running board thats been cut down.Its an interesting thing... like the springs and wheel choice are way underated for this trailer. Axles themselves appear to be solid, so will put these aside. For interests sake I drove the BA up onto the back at the shop. Wouldnt want to make it a flat deck, mainly cause of the extra weight. Has to be under 4.5 T.Thinkin something along the lines of a pair of 2.5 T braked (Dexter?) axles with Cruiser stubs. If I follow thru with this trailer would just buy complete axle setups. Of course would have to run a converter on the brake controller line for plug. LED lite setup will be able to interchange volts wise, so no issues there.No luck with a pintle hook on the truck. Truck's owner doesnt like em either it seems. Cant justify buying my own; purchase/running costs etc... So am investigating a 70mm ball setup. Havent committed funds yet until I come across something that one can swap the ball over with a 50 mm (hopefully something exists). Or at least a 50 mm that has a bolt the same diam as a 70.

Anyone seen something like this in Oz? Suitable for 70 mm as well naturally

Cant see why they would be a legit thing, but knows with some of these the rules around these days.