GRP151

The PRO'S and CON'S of the swivel wheel trailer

100 posts in this topic

I'm just getting ready to start another project. It has been described as a 'swivel wheel trailer', or even a 'Single wheeled trailer'.

 

Although I think I would prefer to call it my 'Supported Cargo Carrier'  SCC

I am hoping that with this terminology it will not be classified as a trailer, why you ask?

 

But first .... one definition implies this

'A box on wheels that is pulled by a car and is used for taking things from one place to another:
The car was pulling a trailer with a motorcycle on it.

The separate back part of a large truck'

 

 
I found it very confusing installing trailer lights on a car that was never designed for a trailer (my 2005 CDi's)
There is not a legal hitch or wiring harness that I have been able to locate for it .
And yes we have all seen Tolsen's boat, stone and wood carrying trailer, albeit its the same one, but not legal here.
 
I'm going to improvise and make this SCC.
I will not be using the standard trailer connections instead I will be using the 2 tow hooks as my stabilized connections
 
The advantage, no plates or lights required
 
 
 
 

SWR_18781.jpg

SCC.jpg

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Posted (edited) · Report post

A trailer contraption like that is dangerous except at walking speeds.

 

Attaching to rear towing eyes is not recommended as not very strong.  Particularly weak in fatigue.

DSC01384.jpg

My tow bar was originally screwed into towing eye threads on above aluminium extrusion bumper.  Fatigue cracks developed after a few days of towing and my tow bar became rather wobbly.  The wooden bumper above is one I had fitted whilst I was exploring how to fix my attachment problem.

 

DSC01398.jpg

My improved tow bar/ towing eye attachment.  8 mm thick marine grade steel plate held on with four M8 stainless steel bolts.  Short partly bored out and threaded stainless steel round bar is double TIG welded to 8 mm plate.

 

DSC01397.jpg

My solution for attaching the fourth bolt.  Note existing bumper only has three bolts each side.

I also beefed up the welds holding existing rear facing square plates of subframe to rest of subframe as these welds are rather poor.

 

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New bumper made out of square hollow steel section.

 

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Tow bar is held on with two special stainless steel bolts threaded to ACME 5/8 x 8 TPI.  These are not available in shops.

 

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I have also cut threads into the heads of the special bolts so I can fit my lowered standard Smart bike carrier whilst tow bar is still attached.

 

Edited by tolsen

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My cargo carrier is designed to carry a max load of 300lbs and to extend no more than 46" out from the rear of the car.

 

It is intended to replace the large and bulky need for a trailer without all the hassel of making bumper modifications to handle the mechanical stresses associated with a standard trailer connection. 

 

I'm not sure why your posting your trailer hitch design, although, since you started can you include the wiring diagram harness?

 

I'm sure you may have sparked an interest for those that would like that.

 

When I complete my project I will post it for those who have an interest.

 

 

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Posted (edited) · Report post

39 minutes ago, GRP151 said:

It is intended to replace the large and bulky need for a trailer without all the hassel of making bumper modifications to handle the mechanical stresses associated with a standard trailer connection. 

 

I wonder why you think that the standard soft aluminium 'towing' holes will be adequate ?

Thus the intent ( you missed ) of Tolsens's post.

 

Those are NOT towing holes, they are mounts for accessories ... like the bike racks.

There are plenty of stories circulating of very failed attempts at using them as 'towing' holes.

 

The front one .. is a 'towing' hole ... mounted in the steel front structural member.

 

I have an aftermarket towing setup.

It has a steel bumper replacement unit.

It also came with a relay box and a wiring diagram.

I can forward the wiring diagram, to you, but you will have to be good with electronics to create the necessary relay setups for the lights.

MyTreeAndTrailer.jpg

 

This picture is, however, just a 'setup'

smart+travel+trailer+75.jpg

 

 

Edited by cadillacman

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6 minutes ago, cadillacman said:

 

I wonder why you think that the standard soft aluminium 'towing' holes will be adequate ?

Thus the intent ( you missed ) of Tolsens's post.

 

Those are NOT towing holes, they are mounts for accessories ... like the bike racks.

There are plenty of stories circulating of very failed attempts at using them as 'towing' holes.

 

The front one .. is a 'towing' hole ... mounted in the steel front structural member.

 

I have an aftermarket towing setup.

It has a steel bumper replacement unit.

It also came with a relay box and a wiring diagram.

I can forward the wiring diagram, to you, but you will have to be good with electronics to create the necessary relay setups for the lights.

 

Yes I would like to see the aftermarket steel bumper replacement and if you would also include the wiring diagram that may be useful for another project.

I have no problems with the electronics, if required, to connect the associating relays.

Thanks

 

 

 

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6 minutes ago, GRP151 said:

Looks like their out of business

I wonder why?

 

yer a little slow arn't you ....

a business making good custom aftermarket parts for a car that never really sold well

 

I wonder why

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Why would you mention a company that makes this hitch that is now out of business? Who cares?

 

Anyway the point is I'm not making a trailer hitch.

 

 and 'If' the weak link here is the threaded inserts that is pressed into the aluminum bumper  then the solution would be to beef up that cavity

 or thread into the mounting plate under the bumper.

 

What I have done was rethread the acme inserts to 5/8 course SAE thread and weld on a stainless steel nut to a modified stainless steel plate under the bumper.

 

What this does is reinforces the attachment of the threaded rod into the rear tow hook threads.

 

...unless your a litle slow and prefer to buy a $500 out of business trailer hitch?

thats understandable!

 

 

 

 

 

 

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people really do try to help you

but you really really try hard at misinterpreting everybody's intent

Sorry that I tried now

 

Enjoy your 'whatever you call it'

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Regarding towing eyes. 

Handbook that came with my 2002 Smart 450 states rear towing eyes are for towing another vehicle and for mounting a base carrier. 

These rear towing eyes are far too weak for towing and I have never figured out why Smart ever stated they are suitable for towing. 

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Posted (edited) · Report post

I think the real reason why he want one of these swivel trailers is he can't reverse.  Come on GRP, admit it!  

Edited by tolsen

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Tow bar wiring.

DSC01414.jpg

Above photo shows where the multi core cable is wired in at left side of luggage compartment.  The box with blue disc is the audible alarm for operation of indicators, a UK requirement for towing. There must be either an audible or a visual indication that indicators on trailer are operational.

No need for bypass relays since there is no system on these cars to warn if a bulb has failed.

 

I did not use Scotch locks but tapped into existing wiring harness by soldering as seen in below photos:

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Gently cut insulation on cable that is spliced into.  Apply heat and pull insulation sufficiently apart.

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Twist and solder.

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Feeding heat shrink sleeves over cable requires the terminal to be pulled out of socket first.

DSC01427.jpg

 

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Multi core cable exits on left side just above left towing eye, see second photo in second post.  Multi core cable terminates in a 7 pin socket screwed onto my steel bumper bar.

 

A second multi core cable is attached inboard on rear panels.  Goes from 7 pin socket fitted in middle of rear valance to 7 pin plug that connects to 7 pin socket on bumper bar.

 

This arrangement allows me to remove rear panels without fiddling with electrical connections.  All I do is pull a 7 pin plug.

 

 

 

 

 

 

 

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Why rear towing eyes are weak:

SmartAluBumperBarLoaded.png

 

 

 

SmartAluBumperBarMk3.png

I made these sketches years ago to assist someone designing a certain cycle carrier.  All applies in principle to your swivel trailer attachment.    The easy way to eliminate local bending and fatigue cracks in aluminium extrusion bumper is to add an intermediate guide plate as shown.

 

Whilst looking for above sketches I found a photo showing my steel bumper bar:

DSC01400.jpg

 

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Posted (edited) · Report post

 

yes I get it, the reinforcement your showing is for the downward force on the pins not the lateral stress.

I don't think your able to grasp the load stress that this design will incur.

The swivel wheel will take the majority of the load as it will be in the center not the end of the carrier. The tow hooks will probably endure 30 - 40 lbs, if that on, a full 300 lb load

Once the inside plate nuts are welded onto the bumper mount there is no need for the aluminum inserts to function except to keep it level.

 

I think I made a mistake sharing this idea here, I was thinking I would get reponses from those that understand mechanical engineering. Instead I'm bombarded with %$@#! 's replies.

 

 

Edited by GRP151
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I am looking forward to the final design and road test.

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Posted (edited) · Report post

Now that looks familiar!!

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Edited by SMARTWRENCH
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The ultimate in trailer technology!

 

Try these manuevers with your trailer, its never going to happen!

 

After seeing this video you will rethink your opinion of this concept

 

 

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The Smart is not easy to reverse with a trailer attached due to the very short rear overhang.  No big problem in my opinion as one can always unhook and wheel the trailer.

 

I recently checked prices for these modern swivel trailers and almost fell off my throne.  Typically three times the cost of a standard trailer.  That will be expensive reversing if you work it out in terms of dollars per reversed mile.

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The 2 wheeled swivel is expensive but the convenience of carrying something large behind a trailer home for example is well worth the investment. The total length of this type of trailer is shorter than a normal trailer since there is no wasted tongue length.

 

As for expensive, I think not, if you have the skills to weld and construct projects as I do. It will cost me only for some welding materials, since 90% of this will be made from scrap material and recycled parts.

I like the low frame design for unloading a car or motorcycle behind the trailer home. The disadvantage  is the increased tongue weight 

 

AnthonyFull.jpg

s wheel 2.jpg

motor.jpg

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Make it large enough so you can carry full size 8 x 4 plywood sheets.

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On 3/3/2017 at 9:31 AM, tolsen said:

Make it large enough so you can carry full size 8 x 4 plywood sheets.

 

That's not the intention for this project. Making it over 46" long constitutes a trailer requiring lighting and plates.

 If  I were to make it larger I may consider making a camper

Like this one without the mirror finish.

As you can see from the channel steel chassis image you would just add the base sheet size for your requirements.

 

 

http://midtown.net/dragonwing/sears swt.htm

 

 

 

 

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Sears 1941 Spring.jpg

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Try to carry a 25 foot I beam in your 10 to 16 foot trailer.

Thats the beauty of the Swivel wheel concept

swivel2.jpg

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