Box trailer build, alu or steel welds?

[rtbcomp]

I saw one that was made of chipboard and just bits of dexion up the sides units were bolted to the wood

A mate of mine had one like that - he bolted the suspension units directly to the chipboard floor. We ended up picking all the bits off the road and putting them on his back seat.

Re channel vs box, I'd use channel and weld strengthening braces across the channel in selected places. This adds strength, keeps it easy to clean and keeps the weight down.

Try to build triangles into the design, this adds strength.

 

[outofthefire]

OUTOFTHEFIRE why do you suggest channel over rectangular box section? would it not be weaker having only three sides instead of four?

my ifor trailer is all channel. Its probably for a few reasons, less messing about compared with box section for galvanising purposes and less likely to trap water when in use too. Also the suspension is bolted to the trailer not welded. I guess channel is better for this too as to bolt to box you have the void in-between to deal with. The torque on mine would surely distort the box over time and loosen? Depends on wall thickness I suppose.

With box you'd always have to sleeve any through bolts - whatever the wall thickness it'll flex and either fret itself away or loosen the bolts. With channel you can bolt to one side (sleeves would still be needed if you wanted to go all the way through though).

Pretty much what these guys say, have the open end of the channel facing to the back so it they fill up with crap.

 

[ddan1275]

When using indespension units bolted to plates that are welded to the channel, would you make an A shape frame to sit the rest of the box trailer onto, or the other way I have seen is the same (suspension onto plates mounted to a channel axle) but then a T shape coming from the centre of the channel axle full length to the coupling with a few triangles bracing the T to the axle.

I can't see a lot of difference as long as you have the triangle braces in place. The difference at the coupling end is either a plate welded bridging the two channels together or one centre piece to mount the coupling to.

Any preferences on channel thickness, it isn't cheap stuff?

 

[outofthefire]

Caravans generally have an A frame and i'm sure generally its only small trailers that have a T shape frame.

 

[ddan1275]

Does anyone know an easy way of working out the height of the trailer so it sits level when hitched to the car. My tow ball is around 17.5 inches from the ground.
The only way i can think of is to get the radius of the wheel and tyre, so 10" wheel with a 4" tyre would be 9" in total,
The depth of the trailer chassis ie (channel depth 4")
then the height of the indespension unit and drop link/arm but if this isn't much how else do you make up the extra height other than going up wheel sizes.

 

[octo0072000]

Drop plate on tow bar

 

[Spark plug]

Put a spacer under the hitch on the A frame.

 

[octo0072000]

13inch wheels also better to get tyres for than 10inch wheels

 

[octo0072000]

13inch wheels also better to get tyres for than 10inch wheels

or cranked A frame

 

[ddan1275]

It was just because my current car has a visible type tow bar at 17.5" but my old car had a detachable tow bar at 19" and you cant add plates to them. Seems the best idea is to keep it at the minimum height then i can always add parts to raise it up if required where as the other way you cant lower it.