OT Trailer ground clearance.

Yes, its Landrover OT, except its going to be a landie pulling it on its trials, but I have just been offered a project to design and build six plus pieces of kit that will be hauled around on their own custom trailers, then, when they arrive on site, they are lowered through the floor of the trailer and sit on the ground surrounded by their support gear in the rest of the trailer but isolated for vibration purposes from it.

For technical reasons, I want the ground clearance of the towed rig to be "as low as possible". The question is what IS permissible ? Is there actually a legal limit ?

Ta

Steve

Reply to
steve Taylor
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dunno but you need to calculate the height of the average bit of road debris and weigh up against the sensitivity of kit and repair issues.

4 inch plus a thou.... (house brick and a bit!)

Of course you could develope an evil streak and build in some deliberate design flaws (I can say that as it's very on topic!) ;0)

Lee D

Reply to
Lee_D

Are you going to have suspension on the trailer or will the wheels be solid mounted? And is it possible to have an axle full width across the trailer?

Reply to
EMB

Its a pretty delicate cargo, so suspension will be important. Axle across ? Possibly. Is that better than separate units ?

Steve

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Reply to
steve Taylor

What I'd do is use duratorque suspension units (I assume they're available in the UK - or at least something like them) as they let you get close to the ground and still have good suspension.

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If you use a full width duratorque axle you can mount it on an eccentric and make it rotate on a couple of hydraulic rams to drop the entire trailer to the ground when it's stationary. I've drawn a horrible usenet picture below - hope it makes sense (end on view of axle - same setup both ends)

II

Reply to
EMB

On or around Thu, 18 Aug 2005 20:06:59 +0100, steve Taylor enlightened us thusly:

don't think so. there are practical limits, of course - for a wide-track trailer, I'd aim at 6" in the centre, minimum. by wide-track, I mean 6' plus.

Reply to
Austin Shackles

In my younger and some would say sillier days I used a very low trailer designed specifically to tow a car whilst the tow vehicle was setup with a camera rig for TV commercials.

It basically had a wheel in each corner, using a rubber monobloc suspension with stub axles.

The deck was lower than the centre of the axles to give the impression that the vehicle was on the road and being driven. There was the ability to raise and lower the deck by the use of four motorcycle style shock absorbers as well.

The front wheels steered by means of the drawbar and various linkages which somehow we connected to the vehicle on the trailer steering so that the "driver's steering wheel" turned (to make it real - bear in mind that the advertising agencies were overrun with "art directors" back in the

80s).
Reply to
Roger & Lorraine Martin

On or around Thu, 18 Aug 2005 22:07:56 +0100, steve Taylor enlightened us thusly:

Separate units can be changed more easily in the event of a failure. You can also do more with mounting them to minimise height - for a smooth ride, you want to be looking at largish wheels, at least 14", in addition to speccing the suspension units right for the job. In order to get the floor height lower you may want to look at mounting the units the wrong way up or the wrong way 'round. normally, the arms are trailing and point downwards at 30-45 degrees, but I see no reason why they have to, as such. Might want to look at ratings if you mount them otherwise, although the movement is not all that great anyway. funny mounting of axles is easier with separate units, but of course alignment is important... axles in one piece are easier to align but do have a straight tube all the way across at a bit more than hub centre height (unless you mount 'em upside down I suppose).

dunno why I'm telling you all this, mind, 'cos one of my many hats is "trailer-builder", when I can find people prepared to pay for 'em. Most people instead go for a rusty old heap and then spend alsmost as much as it'd have cost 'em to have me build one in repairing it...

Reply to
Austin Shackles

You have that problem too - it's obviously a worldwide syndrome.

Reply to
EMB

On or around Fri, 19 Aug 2005 09:43:26 +1200, EMB enlightened us thusly:

Indespension or Peak in this country. simialr system though.

that's what my big trailer does, except that the axle beam is mounted in circular things and the beam just rotates. >

Reply to
Austin Shackles

On or around Fri, 19 Aug 2005 09:55:57 +1200, EMB enlightened us thusly:

people are strange... as they said in the song.

chap up the road spent 600 quid on an unsuitable trailer (too heavy for the car) with a rotten floor, dubious mechanicals and no gates. He then paid me about 100 quid to repair the floor and make new gates (livestock trailer) and paid someone else to fix the brakes and replace the tyres. For about

200 quid more total he could have had a purpose built one which would have been a lot better suited to the job...
Reply to
Austin Shackles

Steve

Have a look at these two sites. The NTTA one is good reference.

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Mike

Reply to
Mike Derrick

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Reply to
steve Taylor

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