Thread: Chris' ute tub trailer build

Heres a photo of the tub and how i got it home. I think 5 pallets were enough, and it sat very well on the road, (despite my mates rusty lightweight trailer). I wanted to turn the tub over and sit on on 5 x 2" wooden cross members I had with me. This was going to make working on it and moving it around the garage easy, but figured the window bar would be too close to the ground. Luckily i had 2 plan 'A's.


20130116_193254-1.jpg


The tub came off a 1988 Mitsubishi triton single cab ute that a guy on Gumtree was wrecking. Got all the mounting bolts and key to the petrol filler. $200. In hindsight i should have got a 7 year old model triton single cab tub, never used (but a bit dusty) for $350 (delivered) from Utetubs Australia over in Dandenong. Especially now that i want to paint the inner surface of the tub.

Outer dimensions of the top of the tub 2340/2350 x 1600 mm, which, from what i can gather, is approximately the same size as the current model Hilux (05'-12') single cab. Older Hiluxes are narrower (1540 and 1520mm) and shorter (~2200 mm).

In terms of the load bearing surface, it was 720 mm from the wheel arch to the front of the tub, and 700mm to the back. Ive measured that if i place the axle at 1180 from the front of the tub i have ~ 10 mm greater distance from the axle centre to the front load area than the rear overhang.

Having a quick mockup to get an idea of the wheel clearance in the arch, so i could hone in on spring camber required.

20130117_091028-1.jpg

Turns out i recon i can get away with standard Eye-eye springs underslung and still have 100mm clearance to the top of the guard.

The underside of the tub has 8 mounting points. The top group of 2 are 1031 mm apart, the next ones 1110 mm apart and the bottom ones 990 apart. What were they thinking? When i first sussed the idea out i figured, by eye, that all mounting points would line up, and hence get away with a rectangular frame with drilled holes in it. Easy!

tub upside down.jpg

Underside of tub with the RHS frame roughly laid out. The top and bottom rows of mounting points will be bolted through a drilled hole in the top surface of the RHS of top and bottom runners. The RHS will have their opening outwards and ill get a 19mm ratchet wrentch in there to do up the nuts from the tub bolts. The two middle rows of mounts will have welded hangers (probably RHS cut at 45 deg as i have offcuts) from the side rails of the frame. They arent shown in the photo.

Given i had to buy probably falcon wheels for the trailer anyway, i had the idea to try to get wheels to match the car. The reason was initially asthetics, but then thinking about it, i will have 2 (or more) spares for the whole rig when out and about. Typically we'll do a 2500km trip North at XMAS and Easter... right when the tyre places are shut. Have a few extra spares certainly wont hurt!

Got these off ebay for $80 from Port Stephens whilst on holidays at XMAS. Could only get two home, the other two are in Sydney waiting for my next trip north. Only two of them had (barely) road legal tyres anyway.

wheels.jpg

They are 16" Subaru wheels off a 2001 GT Forester.

According to Understanding Tires and Wheels: FAQ, Subaru sizes, codes

most foresters wheels are: 16x6.5", 6.5jj, offset 48 with PCD 100. With metric 12mm 1.25 mm pitch wheel nuts.

And thats whats my Foz has, as its the standard Diesel model. The premium model has 17" wheels. As all wheel drive cars should have tyres with a similar tread depth on them, i will replace all 4 tyres on the car at the same time, when probably only one will be shot. They've already done 65,000 kms, so it wont be too long. Ill then get those old tyres onto the 4 spare trailer. Better still, the cars leased anyway, so it all helps my tax bill.

When i bought the rims, i got the bloke to measure the inner bore to be sure they would fit over a trailer hub. He told me 60 mm. Dean at Marshall Engineering (where i have ordered the trailer kit from) told me they need 56 mm clearance for 55-55.5 mm hub diameters. I measured the (steel) spare on my car and its bore was 56 mm, so i thought i was sweet and the purchase was low risk. However when i took a closer look, i discovered their is a lip thats used to hold the inner plastic "Subaru" cap, that was 52 mm diameter. The outer bore is 60mm at the front, but internally its 56 mm. It can be seen pretty clearly in the picture below.

20130123_085730-1.jpg

After a bit of an angry panic i got out a file and pretty easily took 2 mm off the ridge. It was an important lesson for me, and one of the reasons why i took on this project - i was probably assuming everything would just 'work' without having to actually solve problems.

The initial budget for the trailer didnt stretch to a canopy, but i had planned to get one eventually. A consideration into buying the tub was around finding (cheap) canopy to fit. I did a fair bit of research into tub and canopy sizes (i had the tape measure with me in the car and would pull over when i found a suitable candidate to measure..... yeah, it wasnt a great look.

As the triton tub was comparatively large, the common older Hilux canopies were going to be too narrow. I thought i was going to end up having to fork out ~ $400 for a second hand current model Hilux canopy, until i came across this on ebay. $62.50 and a drive to Taralagon (ive never been to Gippsland, so didnt mind it) and it was mine.


20130124_204456-1.jpg

Its dimensions are 2340 x 1575 mm. 50mm high at the front, 60 mm at the back.

Pity about the colour. Bodyshops i rang up want ~$400 to paint it white. Looks like its staying red.

Gas lifters were still working, has an internal light and sliding windows. One flyscreen needs replacing and didnt get any keys; even so i figured i had a bargain.

Should look very nice when it's finished.
Kryn

I bought a "DIY" trailer kit from Marshall Engineering Brakes over in Bacchus Marsh.

They are way way over the other side of town, but then again as a non-native mexican, i hadnt been there before and picked the gear up on the way home from the airport from a work trip (It was better than fronting up to work that day!). I spoke to Huntsman (they are closer to home) but they couldnt do the 5x100 PCD Subi hub pattern in their standard kits, even though they seemed a bit cheaper than Marshalls. Dean Marshall was really helpful, promptly answering my emails and was always on the ball when i spoke to him on the phone. Given i didnt yet know what i was doing... i figured ii was investing in their know how and experience if i got stuck.

I got their basic 750 kg kit, upgraded to:

1T per pair Eye-eye springs (5 leaf 60 mm wide)
1T 40mm square axle
The hubs with subi 5x100 PCD, 12mm 1.25 pitch studs
Coupling, coupling plate,
U bolts, fish plates bolts etc.
The 6 spring mounting bolts had nyloc nuts, the rest were with spring washers.

Plus:

6 m 5 core wire + flat coupling
2 yellow side and 2 forward white reflectors
Compliance plate (for $18 ###??)
2 x 60 cm 750 kg rated chain

For $369.

20130210_134808.jpg20130210_134757.jpg

Assembling the bearings was an interesting experience. It was explained to me a number of times by different people... without anything to look at. In the end i found a good Youtube movie showing how to do it. The first bearing sleeve (what are they called?) i installed i realised was around the wrong way.... luckily it was only 1/2 the way in and i could get it out. One nights work had them pushed in and freely rolling on the axle. I took one into work for one of our tool makers to inspect, and he gave me the thumbs up. I left the greasing until later, as i was trying frigging around with the axle placement and had the wheels on and off a lot. When i did pack them with grease... all went well except for the last cap.... was a right pain to get on.

I was trying to match the track of the original Triton ute, as i was worried about the wheel clearance in the arch. I measured the outer wheel dimension when i bought the tub:

20130116_193038.jpg

ie 158cm. We figured that meant i needed a 62" axle.

Note: remember to find and include that calculation.

After installing the wheels their outer separation was... surprise surprise... 158 cm!!

Based on reccomendations from around the place, and what a number of builds over at myswag.org, i went for 50 x 50 x 2 mm RHS for the frame, and 75 x 50 x 3mm for the drawbar (Thanks Yonnee).

I priced high tensile bolts to go through the RHS to the tub mounting points, and they were a fair bit of paint worth. I still had the original mounting bolts, so i decided to use those. I experimented with a number of ways to do that simply, and with the minimum amount of welds required (ie simple). Heres what i came up with:

20130124_231532.jpg

I got the steel from Melsteel Pty Ltd - Melbourne's most experienced Steel Sales and Fabricator whom where the cheapest i could find. The frame was basically 1 x 8m full length (including cutting). The drawbar 75x50x3mm were 2.45 m long. All up that cost me $100 ($50 less than my original budget!!!).

Laying it out:

20130210_134539.jpg

I was considering the location of the cross members. I wanted them to be located with the spring hangers, thinking it would help any torsional twisting. But that space at the front of the tub is just perfect to stick up a spare tyre and be well hidden. I wasnt sure if i was going to put it there, or on the A frame... or both as i have two.

20130210_134727.jpg

We deceided we would tack up the frame with everything bolted in place, so that the pre-drilled holes would easily line up. The next few photos show that, with metal washers as the correct height spacers as i didnt want to put the fibrous bush material in in case it got too hot. Also the M8's shown were just for the welding...i had already lined up the brakets with the 12mm tub bolts.

20130210_134548.jpg20130210_134556.jpg

This is how i did the 4 corner mounts. I wanted to keep the RHS square as i will buy plastic caps to keep the water and crap out. I did a lot of tests with 19 mm spanners to make sure it was possible to do them up..... I was.... but a bit painful and slow.

20130210_134608.jpg

Especially without the bushes (for welding) so that i couldnt use a ratchet ring spanner for most of the tightening.

The actual full bolt assembly looked like this:

20130210_134640.jpg

So there should be no metal-metal contact between the tub and the frame.

Once i figured out where i wanted the axle to be, the hard part was figuring where that meant the spring hangers went.

Also, i was concerned about the trailer height, and at one stage in my planning thought it need outback springs with the axle over slung to get enough clearance. In hindsight i was way wrong, but still dont know how. I figured these springs underslung would give me heaps of clearance and a perfecly flat trailer to match my tow ball.

The drawing was provided by Marshalls. I measured the springs and annotated on them.

20130211_001503.jpg

I determined the 409 mm number by laying out the spring sideways and using a large t-square to project back onto a flat inline with the hangers. I also then had the space between the hangers (but i didnt write it on that drawing!).

20130210_192333.jpg

Our alignment was the following:

We loosely did up the U-bolts and first checked the axle protruded from each spring the same amount (ie the axle should be sideways centred).

Then we measured from the center of the apex of the A frame (before the coupling was mounted) and measured from that point to a similar point on each hub... and adjusted accordingly until they were to within 1 mm of each other. 1 mm seemed to be the best we could do given the approximation of locating the same place on the hub (in fact we used a point on the grease cap, which may not have been the best place). We then figured the axle was then square to the center of the A frame.

But the holes in the coupling plate have about 1mm play.

So what would be a better way to align the center of the coupling (ie the ball center) to the axle perpendicular such that it tracks straight..... Any clues from the old hands?

One of the technicians at work is building his own independant suspension (with 4 independant airbags). He kindly offered to come teach me to weld. Even so, i was always going to make him to the critical welds (ie spring hangers, drawbar, coupling plate etc).

Placeholder for editing later

This is how we attached the chains. It seems like a good idea at the time, and i have to admit i hadnt thought about chain placement at all. (Note the photo is from the bottom)

20130210_183339.jpg

I was told one of those chains would be enough to comply with the ADR's for a 750 kg trailer. So why not have two!

The chains did seem to fall nicely and keep out of the way when attached to the car.

Any comments?

A quick update -

We got a little over excited. We did all the welding and assembly in 6 hrs. Then 3 of us managed to roll it over without squashing Alex my son... whom didnt seem to want to stay on the white tiles as per my instructions.
I wished i had photos of that.... the rolling i mean.

It just had to have a (short) road test hmm .... rego... wiring... remembering to tighten up wheel nuts....

Even so, it pulled remarkably well. No wobbles, tracked short turns well, seemed to pull straight (well from the passengers seat vantage point). Didnt rebound much when going over a gutter. Even though i think the A frame looks too long, it sure does reverse well.

I used bathroom scales under the wheels and then me holding the drawbar coupling - total weight 283 kg, including 17 kg down on the ball.

20130210_194910.jpg20130210_194929.jpg


20130210_195944.jpg20130210_200050.jpg

Originally Posted by drwormy

Once i figured out where i wanted the axle to be, the hard part was figuring where that meant the spring hangers went.

Also, i was concerned about the trailer height, and at one stage in my planning thought it need outback springs with the axle over slung to get enough clearance. In hindsight i was way wrong, but still dont know how. I figured these springs underslung would give me heaps of clearance and a perfecly flat trailer to match my tow ball.

The drawing was provided by Marshalls. I measured the springs and annotated on them.

20130211_001503.jpg

I determined the 409 mm number by laying out the spring sideways and using a large t-square to project back onto a flat inline with the hangers. I also then had the space between the hangers (but i didnt write it on that drawing!).

20130210_192333.jpg

Our alignment was the following:

We loosely did up the U-bolts and first checked the axle protruded from each spring the same amount (ie the axle should be sideways centred).

Then we measured from the center of the apex of the A frame (before the coupling was mounted) and measured from that point to a similar point on each hub... and adjusted accordingly until they were to within 1 mm of each other. 1 mm seemed to be the best we could do given the approximation of locating the same place on the hub (in fact we used a point on the grease cap, which may not have been the best place). We then figured the axle was then square to the center of the A frame.

But the holes in the coupling plate have about 1mm play.

So what would be a better way to align the center of the coupling (ie the ball center) to the axle perpendicular such that it tracks straight..... Any clues from the old hands?

You've pretty much got it spot on.

Originally Posted by drwormy

This is how we attached the chains. It seems like a good idea at the time, and i have to admit i hadnt thought about chain placement at all. (Note the photo is from the bottom)

20130210_183339.jpg

I was told one of those chains would be enough to comply with the ADR's for a 750 kg trailer. So why not have two!

The chains did seem to fall nicely and keep out of the way when attached to the car.

Any comments?

You've ticked all the boxes as far as regulations go, nothing wrong with two chains.

Thanks for the confirmation Yonnee re alignment and chains.

If i did the alignment again would there have been a better way? Ie taking hub off and measuring to the end of the axle? Also, people talk about 'pulling straight'. Technically what does that mean exactly (ie i assume it means the trailer wheels tracking with the towing vehicles) and how can i get a feel for it pulling the trailer? Should i have a mate follow me and make a movie or something?

Also, tonite I went going through VSB01 for a final check off before making my rego appointment.

Found the section on chains -

16.3 Drawbar Safety Chain Attachment Points

Caution - Drawbar safety chain attachment points should not come into contact
with the road surface when the trailer is disconnected.

I think through luck rather than planned measure my chains will comply.

But in the lighting section ive come up against something unexpected.

13.1 Front Position (Side) Lamps
These lamps indicate the presence and width of a trailer when viewed from the front.
Presence: Must be fitted if a trailer is more than 1600 mm wide and over 4 metres long, or over
1800 mm wide.
Number: 2.
Arrangement: At the front. S

When i measured the length of the trailer it came in at 4100mm, but is ~ 1603 mm wide. Measuring to the end of drawbar... its ~ 1750 long! I think i must have overlooked the protrusion of the 50mm coupling, and the exact location of the front spring hangers, as it wasnt meant to be longer than 4m.

Technically i need the Front Lights.... im wondering how crucial it would be if i skipped them. Can anyone suggest what type of light im going to need to comply with VSB01? Bit of a bugger actually, as now i have the extra hassle of getting wires in there.


Finally, i didnt put a A frame cross member on the drawbar as we ran out of time. I can detect some roll in the drawbar as it is, so will put one in. Should also serve as a place to mount the spare. If i had done more planning i would incorporate a bike rack here as well, but that will have to be a later addition. I have spare 75x50x3mm. On various trailers ive seen, some put the 75 mm in the horizontal plane, some in the vertical, and some more have a "T" arrangement, with a rail running from the centre of the cross member back to the front of the trailer frame (ie down the centre line).

What are the advantages of each of those 3 options? Does the centre member help with anything?

Cheers Chris.

Plus or minus a couple of mm won't make bugger all difference to the tracking on a single axled trailer. Even if it's out by 10-20mm, then all it will do is crab to one side slightly. But the closer you get it the better. It's a little more critical on a tandem, as the two axles try and fight each other if they're not pretty much parallel. Having said that, most trailer suspensions are pretty crude and have at least a few mm of slop when on the road, so it's never going to handle like a racecar.

Whenever I align the axle/s, I do it with the coupling bolted on, and run a tape measure from the front of the coupling. Check both front to rear alignment and side to side alignment each time you make an adjustment too...

As for your lights. The regulations changed a few years ago, and were re-written slightly to partly comply with European specs, but they only served to complicate how they're interpreted. Quite often you'll get an inspector who doesn't fully understand the reg's either, so it could possibly pass without them.
HOWEVER...
The onus to have the trailer ADR compliant falls on the manufacturer of the trailer, for the life of the trailer, as well as the onus of keeping it roadworthy falls on the owner. So in the event of an accident (particularly a fatality), all factors are investigated, including roadworthiness and compliance of the trailer. I personally have had a few near misses with trailers that could not be seen at night, and I prefer to have my trailer lit up like a Christmas Tree, so for the effort involved to get it right short term, will give you peace of mind long term.

It's because your drawbar is quite narrow for its length that you're getting some torsional twisting. A cross piece part way down its length, run in the vertical plain, will help reduce this greatly. As for an extra longtudinal section from this cross piece back to the front cross bar, this really doesn't help to do much at all, as the original triangle is quite sufficient. It will help stabilise a spare wheel on trailer with drawbars too wide for the tyre to sit properly.

Thanks Yonnee for the advice.

Originally Posted by Yonnee

It's because your drawbar is quite narrow for its length that you're getting some torsional twisting. A cross piece part way down its length, run in the vertical plain, will help reduce this greatly.

Is there a suggested distance for "part way". I am planing to put in such a cross member, and was looking at 1/2 way along last night, but suspect closer to the apex would be more effective? Any thoughts?

Also, i got the forward lights installed, compliance plate on, all wired up and got it rego'ed last week. (Had to drive 1 hr to Warragul as the local Vicroads had a 2 week wait for new Trailer appointments. A shame as the appointment took less than 5 minutes!!).

Took it for a good run (40kms) down the new Peninsula Link Freeway, and afterward checked for any bearing heat etc and tightened spring and U bolts. I had neeb asking around if anyone at work needed anything heavy moved this weekend, to test the trailer out underload, as its maiden real voyage is to Sydney and back next weekend.

Pretty happy with the outcome, except for the drawbar obviously looking too long. Im probably going to shorten it down the track.

Costs so far:

Tub $200
DIY trailer kit $369
Wheels $80 (for 4)
Wheel nuts $5
Steel $110
Rego+plate $63
Welding costs $125
Canopy $62
Jockey Wheel + front lights $64

So pretty close to $1K

Future plans are:

Drawbar crossmember (and maybe shorten it)
Paint the chassis (which means taking it all apart )
Build a bike rack in front of the tub for 5 bikes.
Mount a spare tyre under the front of the tub
Cut off the window bars off the tub to fit the canopy, and make up some brackets so i can bolt them back on when the canopy is off.
Start to fit out the interior to be camping friendly (ie raised floor, storage bins underneath, mattress).
Learn how to work with sheet metal and build a large front unit with slideout kitchen etc.