Car trailer - dimensions for custom made one?

I'm currently getting a trailer built to my own specifications; basically I want it as large as possible but still be able to stand up on its rear end in my garage and fit through the door, for storage - that is a fairly severe constraint, 77.5" max. Question is, what dimensions can I get away with for (a) the length of the towing coupling and (b) the width of the trailer? Obviously if (a) is too short and (b) is too long, then the corner front of the trailer will hit the car when I turn a corner or reverse. If I err to far on the side of safety then I waste volume of the trailer.

Isn't there a 'standard' answer for this? I can't find any info about it anywhere on the web or usenet.

At the moment, I'm going for a 48"-square trailer (excluding coupling)

- does that sound OK?

Thanks David

Reply to
Lobster
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| I'm currently getting a trailer built to my own specifications; | basically I want it as large as possible but still be able to stand up | on its rear end in my garage and fit through the door, for storage - | that is a fairly severe constraint, 77.5" max. Question is, what | dimensions can I get away with for (a) the length of the towing | coupling and (b) the width of the trailer? Obviously if (a) is too | short and (b) is too long, then the corner front of the trailer will | hit the car when I turn a corner or reverse. If I err to far on the | side of safety then I waste volume of the trailer. | | Isn't there a 'standard' answer for this? I can't find any info about | it anywhere on the web or usenet. | | At the moment, I'm going for a 48"-square trailer (excluding coupling) | - does that sound OK?

Mine is 5ft by 3 ft and stands on its (lights) end in the garage, with the towbar inside the roof structure. It takes up little room like that.

Get yourself a tape measure, and a large sheet of drawing paper, (or a CAD program) and plan the job properly.

Dave F

Reply to
Dave Fawthrop

I don't know about any published rules, but I have just measured my Daxara trailer. That has a body length of 59", and the hitch length - to the centre of the towball - is about 28", making the overall length about 88" - which would seemingly be too long for your purposes. I think that 28" is reasonable for the hitch length, though. Any less, and you're in danger of the trailer hitting the car on tight turns. That would seem to fit ok within your 48" body length and 77.5" overall length suggestion.

I presume that 77.5" is the height of your garage ceiling? The trailer may have to be less than this in order to fit - depending upon whether the effective pivot point on the back, when in the process of standing it up, is at the same height as the hitch when the trailer is horizontal. If it isn't, you'll have to cater for a diagonal, and will need to invoke our old friend Pythagoras.

Axle position is also important. To make it easier to reverse **, the axle needs to be as far back as possible. However, if you put it too far back, too much of the trailer's load will be imposed on the towball rather than on the trailer's axle. You should aim at a hitch load of about 7% of the trailer's fully laden weight - provided this doesn't exceed your towbar's max. permissible hitch load.

I believe that all trailers these days have to be fitted with a plate which specifies unladen and fully laden weights (and maybe other things?). I presume that you are getting your one-off trailer plated, in order to comply with the regulations?

** If you're interested in the mathematics of trailer reversibility, see
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trailer of the dimensions you are contemplating is going to b****y difficult to reverse compared with (say) a caravan].
Reply to
Hitch Lock

"Lobster" wrote

Hello David,

I built a trailer based on a caravan chassis when I used to go banger racing.

Before I did, I went to the library (no internet in them there days) and found a book, which was published by Indespension, for home builders of trailers using their parts. This had several plans for trailers, and gave an enormous amount of advice.

It is especially critical to make the A frame at the front sufficiently strong, and I remember there was a table showing the strength of steel and dimensions required according to the weight of the towed vehicle and other factors.

Personally, in your situation I would find a trailer of the type you require, ask the owner if you can go over it with a measure, then build it to the same sizes.

-- Regards, Vince

Truck Driving In Russia-

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Reply to
Knight of the Road

Well basically I've already done that... the dimensions I've quoted above (a

77.5" long trailer overall, with a 48"-square load area will fit fine in the garage (77.5" is the garage door height; can't go any longer than that as the garage is too full so I will have to stand it up just inside the doorway). That gives 29.5" for the coupling length. If I draw out a plan of the trailer hooked to the car, then yes, I'd be able to work out the max possible angle between the car and trailer when turning a corner; however I don't know what that angle ought to be to be safe. That's my query in a nutshell, I suppose.

David

Reply to
Lobster

An afterthought . . Have you considered making the whole thing longer by using a de-mountable hitch? It this hinged into the upright position, or even folded away underneath, before standing the trailer on end - but locked solidly into the horizontal position for towing - the body length rather than the overall length could then approach your ceiling height limit.

Reply to
Hitch Lock

I built a trailer some months ago and like you I could not find any information on the web, well not for free any way, everyone wanted to sell plans. My trailer is slightly bigger than you want at 93 inches overall but is absolutly rock solid on the road The dimentions are, Body width, 42 inches. Body length, 61 inches. Body hight, 16 inches. Drawbar including towhitch, 32 inches. I would advise shrinking yours down to the size you want *proportionatly* (the drawbar of my trailer could have been 2 inches shorter but no more than that and I would have moved the axle back a couple of inches for stability) as you dont want a trailer that is wider than its length, You sugest a width of 48", depending on the wheels you fit you could end up with a trailer that is as wide or wider than your car which means you clipping the kerb at every corner. I have emailed you a (bad) drawing, hope I have helped If you want me to send a photo of my trailer let me know (via group unless you can work out my spamtrapped e-mail address)

Reply to
Drew

You could always try bringing in the front corners a little, so that you maximise space and minimise the crushing situation.

Pete.

Reply to
Pete Smith

You can always hit the trailer reversing.

If the tow coupling is at least half the width of the car, I think it unlikely that you would be able to cause the trailer to hit the car whilst going forward.

It helps if you can see the trailer from one of your mirrors otherwise reversing may be difficult if not impossible.

I store my trailer on its side, the mudguards are strong enough.

Michael Chare

Reply to
Michael Chare

Why not make the drawbar removable for storage?

Reply to
SimonJ

You might try Towsure - I'm sure they had a booklet you could buy which gives all sorts of information about building trailer, inc regulations etc.

They also do chassis etc in different sizes & capacities - these tend to have a single drawbarrather than an"A" frame.

To get some idea of dimensions - go to B & Q or Halfords and measure their trailers.

Also think in terms of what would happen if you turned a tight corner, - would the drawbar be so short that the trailer body would hit the car?

have fun.

Reply to
Richard Murphy

Contact Indespension. IMHO (and experience) they know *far* more about trailer building than Towsure.

BOL Richard

Reply to
Richard Savage

Interesting.

I am looking for a small (5' x 3' or 4' x 3') trailer for moving computers. It must have soft springing, perhaps the old fashioned leaf design.

Any suggestions, anyone, on where to get such a beastie?

Reply to
Alasdair Baxter

============================================= Get a Welder to make you the box section, then go to a srap yard and take the Back wishbone of a Mini.

Reply to
Grouch

| On 21 Feb 2004 05:31:41 -0800, snipped-for-privacy@hotmail.com | (Lobster) wrote: | | >I'm currently getting a trailer built to my own specifications; | | Interesting. | | I am looking for a small (5' x 3' or 4' x 3') trailer for moving | computers. It must have soft springing, perhaps the old fashioned | leaf design. | | Any suggestions, anyone, on where to get such a beastie?

The springing on *all* trailers is IME too hard for computers, *without polystyrene packaging*. Both my small leaf spring trailer, and my ALKO torsion rubber spring van are IME too hard, for computers. I always carry computers, in the car, on a seat, and strapped in.

There are *lockable* box trailers, available, which could be made suitable with additional padding.

Dave F

Reply to
Dave Fawthrop

You sugest a width

[T] Em, you don't *have* to clip the kerb at every corner Drew ;-)

I tow a two wheel camping trailer behind my motorbike and obviously the trailer wheels are wider than the wheel track on the bike. You just have to remember you are towing (as you would remember you were in a wide vehicle). The body of the trailer is infact 2" narrower than the bike with it's touring cases on so filtering in traffic isn't any more of a problem with the trailer than without!

I built my first trailer to my own design many years ago to tow behind my Messerschmitt bubble car. It had to be *very* light and had a flat wooden (T&G) 'bed' and used motorcycle suspension units (they gave a much softer ride than any commercial suspension unit for the weight / load of the trailer).

My next was a 1/2 ton, braked box trailer starting with the 6' 6" x

48" Indespension chassis and going from there. I still have and use that over 25 years on ;-) (It was built as a 1m high 'box' then got cut down to 18" high to be general 'goods')

The other trailier (that *won't* clip the kerb) is the single wheel one we tow behind the tandem cycle ;-)

A final tip (depending on what you are likely to use the trailer for) is I fit 4 screw eyes through the bottom of my trailers right up against the inside of the sides and at about 1/3 and 2/3 down the length of the trailer (often into a crossmember or at least the frame). This allows the use of straps to say hold down a motorbike in the trailer without having to go round the outside or round mudguard irons etc.

All the best ..

And tow safe ..

T i m

Reply to
T i m

[T] Wishbone? Do you mean subframe and you don't want the hydrolastic suspended one!

As Dave mentioned I don't think you will *easily* make a trailer with a soft enough ride to carry computers (well, depending what size of 'computer' we are talking about ..PC's or PDP11's ).

You can get 'Softride' suspension units from Indespension (used to be called Flexitor units I believe) but they would still shake the PSU out of a single PC (ie unloaded) in the trailer.

I bought a trailer off a bloke who wanted to use one to carry clothes on a rail. No matter what he tried they were all on the floor of the trailer when he got to the other end? ;-(

The only trailer I know that is 'really' smooth is the type we tow behind the motorbikes. These are Squire D10's and have independant leading link wishbones using rubber in compression (rather than torsion like on most designs) and tiny hydraulic dampers.

They really do 'float' along and the laptop survives in them ok ;-)

All the best ..

T i m

Reply to
T i m

I would never move anything as fragile or valuable as computer equipment in a trailer - the bumping a jarring is certain to do some internal damage.

CPU's go on my back seat, strapped in and/or padded.

Screens ditto, but the CPU is what counts. Even a laptop in a padded case.

Reply to
Richard Murphy

i'd have to agree , given that LDV ( when still either leyland daf vans or even freight rover ) decided one way to increase their return on the investment in air suspension for the sherpa300/400 was to sell it for movin computers and other technology equipmentas well as to give a reduced loading height in Ambulance / welfare bus use

Reply to
Martyn Hodson

Hello Alasdair

Um, tricky. Small trailers are all hard springing IME. The only way you get them to bounce smoothly is to make them extremely heavy - over a ton before you get a decent ride. It's the same with a car, and they have much more sophisticated suspension, plus with a trailer you as a driver are quite insulated from what it's doing and your speed may creep up over bumps that lead to the trailer flying. (Very easy done with a light trailer).

Maybe for short distances over good roads, you could weight the trailer down with blocks to smooth it, but I wouldn't personally like to do this given the high value nature and fragility of the cargo.

Reply to
Simon Avery

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