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My custom 3 bike trailer
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TOPIC: My custom 3 bike trailer

My custom 3 bike trailer 7 years, 6 months ago #1646

There is a full version of this thread over on the trailrideraustralia forum;
http://www.trailrideraustralia.com/viewtopic.php?f=341&t=2516

but I thought I'd put a condensed version here for you guys to check out.

So I decided that I wanted a bike trailer for my dirt bike. I'm a mechanical engineer and like to design and make stuff myself, so I started searching the net for bike trailers to use as inspiration.

My requirements were simple, it had to;
* be light
* also be a box trailer
* convert from bike to box trailer quickly
* fit 3 bikes
* be 750ATM (QLD light trailer)
* have a spare tyre
* have LED lights
* have storage boxes
* look cool

So I found some KTM CAD models on the net, drew the fatter DRZ radiator shrouds onto them to get the right width, and laid out a basic trailer CAD model.



So that set the basic design. I then started getting all of the part, and drawing them as I went. That way I could update the CAD model and get more detail of how I wanted it all to work. So the CAD model ended up looking more like this once detailed.





My plan was to make this at my friends house as he has a rather ridiculous workshop set-up. He also has experience TIG welding aluminium, whereas I don't. So in order to make sure he does the right thing, and I don't have to explain everything in person, I made him a set of drawings. They need updating as we made a few little changes along the way, but these are mostly correct;

http://www.offroadvw.net/trailer/plans.pdf

Another friend decided he wanted one too, so we ended up making two at once just to make things more difficult. So we ordered all the parts and got going.

So before we got too far we had to get the Torchmate CNC plasma cutter going, as it was a new toy that hadn't been used yet. We had a few little issues, but got it cutting good enough to do what I want on the trailer






Most of the frame is 50x50x2 SHS. I have some 50x50x3 EA pieces for the bracing of the aluminium sides.


I bought some second hand commodore mags, got new tyres for them and a new set of wheel nuts for the weird 7/16" trailer hub studs.


I used a 75PFC for the draw-bar, with triangles cut out to save a bit of weight. It has very little effect on the strength and has basically turned the PFC into a truss.


We did the main folds for the aluminium deck. We had to call for extra help as my 60kg of body weight just wasn't enough to operate the pan break properly :)


It was decided that the draw-bar brace needed to be something different, something fancy. So here it is;


We folded it to make it strong. The weird shape above is what was needed to fit neatly into the PFC drawbar.


You can see here that I skipped the triangle draw bar cut-outs where we needed to bolt the jockey wheel.


We decided on a cage for the spare wheel, something the tyre can just slide into. And yes, there are Alpacas in the shed :)


Then we had to top work on the trailer to build an internal wall in the shed to separate the plasma from us, before the dust and fumes killed us :) We put in a sliding door and window so we can see it working.



This next part was done during Brisbane's non stop rain period. I would've liked to spray paint the chassis for the trailer, but I know it just doesn't work so well when it's raining. So we resorted to hand painting it with small paint sample rollers and brushes. I've gone for aluminium coloured Killrust as I know it goes down fine in any weather by brush, I know it smooths itself out pretty well, I know it works pretty well, and best of all it's very easy to reapply or touch-up. I will respray all the exposed parts once the weather clears up and I have a free day on a sunny day.







We had many hold ups on the project, like waiting on new plasma consumables to arrive from the US so we can cut more parts. Also my mate and I both have busy lives so it was hard to synchronous our time to work on the trailers.

I got all the axles fully bolted up, centered and aligned on the trailers. It took a lot longer than expected but now it's done. I've also had to do a few small changes as the axles are a little longer than they should be, but are still workable with some small changes.

Also started TIG welding the decks together and welding the 50mm end caps on. These help stiffen and straighten the ends of the deck, plus protect the steel frame in that area.







We got the end caps on the deck, cut all the piece for the front and rear gates for both trailers and the bits for the wheel arches. All the gate pieces were folded up and ready for welding out.

I also added some cool engraving on the gate infill pieces. These pieces face outside of the trailer, while the 3mm checker faces inwards. In this pic you can see an upside down 3mm checker gate piece folded, with the 2mm engraved aluminium infill piece sitting in it. Near the top are the little folded triangle pieces for the wheel arches, which are smaller and simply then what is in the current drawings and CAD images in this post.



Soon the trailer was basically a box trailer. The gates are all welded up, I still want to add a couple of little gussets later though. The wiring has been routed through the chassis which is a slow process, but it means the wires are hidden and protected.

I have designed the hinge positions so that the front gate folds down onto the draw bar and is then sitting flush with the deck. So if you want to carry something longer than the deck it works like a deck extension;


I simplified the wheel arch design to two triangles. You can see where the storage boxes will go;


The rear gate is mounted. It houses the numberplate. The LED tail-lights are mounted behind the rear panels, so that they are well protected from accident damage, the same as my car rear lights;


The license plate is mounted in the recessed part of the gate. The tail-light has LED's which point out to the side. So I put a long elongated slot on the gate, and drilled 4 holes to line up with the LED's in the deck;


I was a little unsure whether that plan would work for lighting up the license plate at night, but tonight I gave it a go and it works great.




So the next thing was to get the bike insert done so the trailer could move bikes. The insert gets held in by 3 bolts. 2 at the front that go down to tabs on the draw baw, they pass through the insert near the middle bike tie down lugs. Then one at the back between the side bike tie down lugs. I decided that once I get bikes on there I'll see if it all seems stiff enough or if it needs more gussets or something, but so far it seems good.







So after that was installed the trailer was ready for use. So on saturday I went dirt bike riding and took two bikes up to Beerburrum. Obviously the storage boxes aren't done yet so there is a gap infront of and behind the wheels.



The trailer tows great, the Baja pulls it no probs. The gates work well for loading and unloading.

And the dirt bike riding was good too! Here are a couple of pics another guy took of me playing on a jump.



Re:My custom 3 bike trailer 7 years, 6 months ago #1647

  • wayno
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WOW ? thats very good , i like it ...

Re:My custom 3 bike trailer 7 years, 6 months ago #1648

  • shanhard
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Nice post mate!

Nice trailer too, love the details.

Re:My custom 3 bike trailer 7 years, 6 months ago #1649

  • Kummo
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  • 2010 DRZ400E
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Thats grouse, How much did it end up costing you?

Re:My custom 3 bike trailer 7 years, 6 months ago #1650

about $2200, plus A LOT of labour :lol:

Re:My custom 3 bike trailer 7 years, 6 months ago #1651

  • Rocker
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  • Never enough time to ride.
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Well done mate thats awesome :cheer: looks bloody good as well.
4 wheels moves the body, 2 wheels moves the soul.
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