Car transporter chassis that comes apart...

[BOOF]

Afternoon all - First post on here so be gentle!

OK So I'm planning to build a mini car transporter, thats a small one that will carry a mini, nothing larger. I am also looking to make it sectional, IE so I can take it apart and store it behind the garage.
(Yes I'm well aware of the legalities of self-building and IVA testing a trailer)

First question is strength - Would 80x40x3mm be chunky enough for a car trailer chassis?

Secondly, connecting sections together, I intend to have some flanges cut from 8mm plate steel, and weld one to the end of each section, then 6 bolts around the outside to attach 2 sections together.
Is this likely to be a week point? (IE the weld of the square tube end to the flat flange)

 

[Robotstar5]

Secondly, connecting sections together, I intend to have some flanges cut from 8mm plate steel, and weld one to the end of each section, then 6 bolts around the outside to attach 2 sections together.
Is this likely to be a week point? (IE the weld of the square tube end to the flat flange)

A smaller box section which could be plug welded/bolted inside one piece then slipped inside the second would be a stronger connection.

...and welcome to the forum.

 

[Kent]

You might find a hinge that works upwards to fold easier to handle?. As for strength a lot depends on were the forces are, the section you suggest might take the weight of three minis if it were in the correct relationship to them but you see it depends, look at the chassis of some modern trucks its not all about how chunky it is.
If your not sure get it calculated or just copy something

 

[BOOF]

Thanks - Yes ive been re-thinking this, I'm now thinking that i can hinge the entire back half of the trailer so that it can be folded up and onto the front half (ie the wheels are then right at the back)

This is what ive come up with for a hefty hinge that should allow this, imagine this being half way along the SIDE chassis member, above the axle.

The thing i was worrying about was the forces when loading would be massive at that point.

 

[rikrobson]

Is this not being a bit over engineered? A mini would not weigh about 700KG tops i would have thought. Your trailer will end up weighing more than the payload. I'd make the trailer as light as possible. A simple frame of 20 or 30mm box and and an A frame to the hitch (40mm Box) two channels for the wheels to run up (ally checker plate in angle iron) and some sides made from 20mm angle. you could make the A frame to the axle and bolt the carrier frame on top, which could be in two sections for storage. the trailer will neet to be braked so you will nne to have the hitch and axle commected in one piece. you could make different tops for the A frame to carry too for a modular trailer.

 

[T0rnado69]

the last time i rented a car transporter trailer to move two cars.
before i took it back, i took loads of pics of it and measurements of each piece.
and it was fully galvanised and all bolted together.
i assume with HT bolts.

now what did i do with that folder.......

 

[BOOF]

Oh it might be over-engineered, but my god its not going to fall apart! looking to weight about 150-200kg all in.

plans are afoot...

 

[winchman]

I would have thought something like this would have done the job?
Its Angle iron and box section, light weight but strong enough for the payload.
Its easy to make it so the axle base and sides just unbolt.

The loading ramp slides under the base

 

[Kent]

You can handle heavy loads on items better with good design than you can using bigger sections. I don't fully get your "fag packet " type drawing so cant say much more.

Completely separate loading ramps are commonly used for this sort of task, if you view them they are strong by virtue of the design not the material thickness. Think how thick and heavy an RSJ might need to be if it was in a solid block

 

[winchman]

I think the Fag Packet drawing is to show the hinge so it can be folded.
As you say good design will make it light but strong, I would use angle rather than box as its cheaper and lighter.
Remember every Kilo you add to the trailer weight its a kilo less load you can carry.
I assume you have the towing weight of the vehicle you are using to tow it and have calculated the final weight the trailer mustn't go over?

 

[Rig Pig]

What about a towing dolly instead?

 

[Wendelspanswick]

What about a towing dolly instead?

That reminds me of the towing dolly I had, have you ever tried to reverse with one! I soon got shot of mine.

 

[Rig Pig]

That reminds me of the towing dolly I had, have you ever tried to reverse with one! I soon got shot of mine.

I've never used one, a mate has just bought one, it will be intresting to see how he gets on with it. I have a small trailer and that's a pig to reverse

 

[Wendelspanswick]

I've never used one, a mate has just bought one, it will be intresting to see how he gets on with it. I have a small trailer and that's a pig to reverse

The one I had the cradle pivoted round the centre of the axle beam so when reversing the trailer would jackknife round the ball hitch, the cradle pivot and the towed vehicles steering!

 

[BOOF]

A dolly is only legal for use when pulling a car for recovery (i looked at that first!)

 

[winchman]

A dolly is only legal for use when pulling a car for recovery (i looked at that first!)

I had to check this my self as I thought it was only A frames but as you say both are unsuitable
Heres the chapter and verse.
https://www.gov.uk/government/uploa..._data/file/408927/a-frames-and-dollies.pdfThe
A frame issue is you will not be able to achieve the required lighting and braking efficiencies.

 

[T0rnado69]

link don't work....



it wasn't said, but i don't know if the OP

wanted me to post the pics and sizes page of this trailer
i rented before i returned it.
its a bit bigger then what he plans to build.
think it was a 22ft or so trailer..