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miggit



Member Since: 12 Jul 2014
Location: Milton Keynes
Posts: 3657

United Kingdom 

I'd be careful using box section for the hitch, the original is solid bar, if you wanted to use box section you'd have to put an incert in it where the pin goes through to spread the load Thumbs Up Yesterday I couldn't spell Engineer... Today I are one!
Inventor of the 'Guide-o-Matic automatic wheel alignment tool'
Former long term L322 owner, Up/Down graded to a Classic Tractor!

Post #366789 13th Jan 2016 1:27am
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Zirconblue



Member Since: 16 Apr 2015
Location: Kent
Posts: 1277

United Kingdom 2005 Range Rover Vogue 4.4 V8 Cairns Blue

miggit wrote:
The ffrr hitch is too low full stop, and there is no height difference between the swan neck and the 'Multi hole' farmers hitch in height. For some inexplicable reason the the adjustable hitch goes down rather than up Shocked I had to resort to a ladder hitch to get the correct height to comply with EU height regulations,


With mine in the middle pair of holes it's spot on for the recommended height for my 2006 ifor williams, it does sit slightly nose down, but it's supposed to do this to improve stability (according to Ifor Williams). It's obviously much more nose down when empty because there's no weight to compress the trailer suspension. My little Erde box trailer looks stupid when empty, but levels out to a much more sensible attitude when loaded. (the middle holes are the same height as the swan neck)

It's not really a 'regulation', it's simply an agreed standard, so in theory car manufacturers and trailer manufacturers will all make their hitches to the same height. If you have an older trailer then there was no real standard height, so it could be anything. If i recall when looking up the spec before, the specified height still has a fairly wide range, and the standard range rover hitch is towards the bottom of the range, top hole on the hitch is towards the middle. The following links say it should be between 350 and 420mm, so thats about 13-16 inches. With the trailer hitch slightly higher (so it's nose down when coupled)
http://caravanchronicles.com/guides/unders...ll-height/
http://www.pfjones.co.uk/towball-heights.html

One thing to note with spacer blocks and adjustable hitches is they should be type approved - there aren't many adjustable drop plates that are. Type approval was brought in to stop people making up home brew tow hitches from bits of scrap and welding them to inappropriate bits of the car, i mean just look at the rubbish homebrew trailers you see people doing tip runs with! In practice the non-type approved ones should be fine, but if you should be involved in an accident, your insurer might use it as an excuse to avoid paying out.

Post #366834 13th Jan 2016 12:23pm
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miggit



Member Since: 12 Jul 2014
Location: Milton Keynes
Posts: 3657

United Kingdom 

Sorry to burst your bubble but you are incorrect,

IVA O1-O4 Inspection Manual, Couplings 50A, Revision: 4 Date: 29/10/2013

States that,

7. With the trailer horizontal and resting on a level surface, Class B coupling heads must be attached so that the coupling point of the trailer is 430+/- 35mm above the ground. ( see notes 3 & 4 & figure 1)

It can all be found here https://www.gov.uk/government/uploads/syst...ailers.pdf

So that is a height range of 395 mm to 465 mm 15.5" to 18.25", roughly 17" ave. Which strangely enough is the recommended height for a tow hitch.

And FYI nose down trailer hitch is totally incorrect as it pushes all the weight forward on to the front axle, it will make for a very noisy tow as the trailer will be trying to lift up all the time and in extreme cases could cause speed wobble Shocked

It should all be level and there should be a 75 to 100 kg nose weight (heavier at the front). Although this is not required on a single axle trailer or tandem leaf sprung set ups, but is an absolute must if your trailer is equipped with Indespension type axles, to maintain even loadings on the tyres and reduce the risk of the trailer getting the wobbles at speed.

Now what you have to bare in mind is that not all range rovers sit at the same height, in fact it would be more accurate to say that it is unlikely to find 2 at the same height, except when they first leave the factory. As far as I'm aware my car has not had the height played with, and with the standard L/R hitch it is hard pushed to make the minimum height requirement let alone the average. I tow other peoples trailers for a living, so I must have hitched 100's of different trailers to my car, and I can honestly say that my hitch is too low, and that is why I had to add the ladder hitch to gain height. Yesterday I couldn't spell Engineer... Today I are one!
Inventor of the 'Guide-o-Matic automatic wheel alignment tool'
Former long term L322 owner, Up/Down graded to a Classic Tractor!

Post #367011 14th Jan 2016 12:18pm
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Zirconblue



Member Since: 16 Apr 2015
Location: Kent
Posts: 1277

United Kingdom 2005 Range Rover Vogue 4.4 V8 Cairns Blue

No bubble burst. If you look at the links I posted above they both agree and disagree with your last comment.

They agree in that the trailers hitch should be those distances above the ground when the bed is level.

However there is a different height specification for the ball hitch on the car, which the car does comply with.

The post you've made relates to trailer manufacturers and the specification the trailer should be built to. The heights for the ball hitch are lower than those for the trailer, so that the trailer has a slightly nose down attitude when towing.

Post #367014 14th Jan 2016 12:29pm
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miggit



Member Since: 12 Jul 2014
Location: Milton Keynes
Posts: 3657

United Kingdom 

It doesn't matter what height the hitch is if your only towing a single axle trailer, it makes absolutely no difference to the way that the trailer tows.

However this is not the same for a twin axle setup, if the trailer is old then there is a good chance that it is on leaf springs with a tandem pivot link in between the springs, which will compensate for any height difference between front and rear. But when it comes to the Indespension axle twin setup, getting the trailer as near to level as possible is a must. This will ensure that the trailer weight is evenly distributed over the tyres and will aid stability when towing.

If you tow an Indespension too low it will bounce and try to level its' self all the time, makes for a very uncomfortable tow and can put unnecessary stress on the hitch, if any thing this type of trailer tows better with the hitch high so that it is pushing down on the car more. Of cause this is all relevant to the nose weight of the trailer, the more nose weight the less you'll notice the nose down effect. But if you can lift the nose of the trailer when it's uncoupled it should be towed level or slightly up, and if the nose weight is negative then you should reload the trailer, to bring the weight forward, otherwise it's a new underpants job Shocked

The trailers that I tow have liquid in the tanks, so level is an absolute must, otherwise your in a whole world of pain Thumbs Up Yesterday I couldn't spell Engineer... Today I are one!
Inventor of the 'Guide-o-Matic automatic wheel alignment tool'
Former long term L322 owner, Up/Down graded to a Classic Tractor!

Post #367023 14th Jan 2016 1:07pm
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Zirconblue



Member Since: 16 Apr 2015
Location: Kent
Posts: 1277

United Kingdom 2005 Range Rover Vogue 4.4 V8 Cairns Blue

Yeah that's true it probably makes no difference to a single axle. Mainly because generally they don't weigh very much compared to the weight of the tow car. Unless perhaps you had an old mini with a 500kg trailer on it.

But the key point here is that the reason Land Rover "get away" with having the tow hitch the height it is, is because it's with in the spec (assuming the cars suspension is calibrated correctly). It's the same height as pretty much any car you can buy these days. Unless you have a really old trailer then the trailer and hitch should be perfectly compatible.

Although Ifor Williams for example say the trailer should have a slight nose down attitude they don't specify an angle. I suppose what they're getting at is its better to have it slightly nose down than nose up so the tail doesn't wag the dog. Nose weight is key though, thé trailer should never be nose down due to the weight on it. It also comes into how the trailer is loaded, the majority of the load should be on the trailer axles not the hitch.

Post #367035 14th Jan 2016 2:03pm
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Alistair



Member Since: 11 Feb 2011
Location: Peterborough / Bordeaux / Andorra
Posts: 7921

United Kingdom 2013 Range Rover Vogue SE SDV8 Santorini Black

Majority on the axle - but you still want 7-10% on the nose

So I'd argue that it's OK to be nose down due to the weight distribution - it's much safer to be nose heavy than more evenly loaded.

Post #367037 14th Jan 2016 2:14pm
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Zirconblue



Member Since: 16 Apr 2015
Location: Kent
Posts: 1277

United Kingdom 2005 Range Rover Vogue 4.4 V8 Cairns Blue

no that's true, i didn't word that very well. The nose weight should never be noticeably pushing the back of the car down (bearing in mind the Range Rover has self levelling suspension). if i recall correctly the Range Rover can take 150kg on the tow hitch, or 250 if you have an empty boot. So if you had a 3.5ton trailer with 10% on the nose it will be overloading the tow hitches downward load by 100kg and the arse of the car will be likely sitting on the floor.

When you see caravans with the arse up in the air and the tow cars headlights pointing at the sky they've definitely over done it!

Post #367065 14th Jan 2016 4:33pm
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Alistair



Member Since: 11 Feb 2011
Location: Peterborough / Bordeaux / Andorra
Posts: 7921

United Kingdom 2013 Range Rover Vogue SE SDV8 Santorini Black

The FFRR is pretty good at self levelling Thumbs Up

I would tend err on the side of slightly overloading the nose than the other way around - I've learnt the hard way and believe me a violently wagging trailer at 60mph is no fun at all Embarassed

I probably had >250kg on the nose here - but that's like 2 fat blokes standing on the tow bar.....

Post #367082 14th Jan 2016 5:28pm
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miggit



Member Since: 12 Jul 2014
Location: Milton Keynes
Posts: 3657

United Kingdom 

I think it's safe to say that if you can unhitch your loaded trailer without the hitch jumping up to chin you, you should be ok to tow. If you've too much on the front then you will struggle with the jockey wheel, and if you've too much on the back then the coupling will be a pig to release, and the obvious mind your chin bit Shocked

I take a mental note of the rear tyre state of bulge before loading, if it looks the same or more bulging then all is ok, but if the tyres look like they have just been over inflated (perfectly round) be warned you is ass heavy and you will need new underpants at some point in your journey Shocked

As for the tail wagging the dog, there are 2 causes, too much weight on the front axle ( which is why I say that level is best) and too much weight on the rear of the trailer that will cause negative nose weight and lift the rear wheels on the car. Not to the point that it will pick up the back, but enough to reduce traction on the rear wheels Shocked

FYI if you find yourself in the unfortunate situation of a wobble, do not try and correct it or drive through it as it will end in great tears, slow down, it is the only safe way to get out of a wobble. If it's really bad then you'll have to be brave and brake, trust me it will end in tears if you try to fight it, you normally only need to slow down 5 mph and it will come good all by it's self Thumbs Up Yesterday I couldn't spell Engineer... Today I are one!
Inventor of the 'Guide-o-Matic automatic wheel alignment tool'
Former long term L322 owner, Up/Down graded to a Classic Tractor!

Post #367148 15th Jan 2016 12:13am
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miggit



Member Since: 12 Jul 2014
Location: Milton Keynes
Posts: 3657

United Kingdom 

Oh I forgot to say, a word of warning to all you chaps who load cars, diggers and the like on your trailers, apply the trailer hand brake before loading / unloading......... Many years ago a chap I knew was unloading an excavator from a trailer with the pickup and trailer pointing down a hill, as the excavator got to the rear of the trailer, it caused massive negative nose weight on the trailer. The net result was car trailer and excavator, with him still inside, all when off on a jolly down the hill Shocked Yesterday I couldn't spell Engineer... Today I are one!
Inventor of the 'Guide-o-Matic automatic wheel alignment tool'
Former long term L322 owner, Up/Down graded to a Classic Tractor!

Post #367149 15th Jan 2016 12:22am
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