optimum trailer angle

Submitted: Thursday, Nov 24, 2011 at 20:03

ThreadID: 90268 Views:3437 Replies:5 FollowUps:8

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ross

Hi I just bought a flat top tandem trailer trailer to tow my camper box around.
I want a choice of either having it on the trailer or on my landcruiser ute,depending on my trip.
The trailer tows terrible behind the landcruiser ,presumably because the tow hitch on the landcruiser is too high.
It tows great behind my commodore with a tow hitch that is about 100-150mm lower.
Behind the commodore the trailer tilts down slightly,behind the landcruiser it tilts up.
Im going to get a welder friend to do some mods,so is there an ideal angle for a tandem trailer or should I just make it the same as my commodore?

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Reply By: disco driver - Thursday, Nov 24, 2011 at 20:35

Thursday, Nov 24, 2011 at 20:35

Ross,
Rather than re constructing the trailer drawbar to suit, why not go to a caravan place and buy either a compromise tongue (one that is mid way between the draw bar height of both vehicles) or buy 2 separate tongues, 1one a bit higher for the Commodore and another a bit lower for the Cruiser .
This would ensure that your trailer tows at the best level regardless of the tug.

It may be a bit dearer than a mate welding something up, but will definitely be safer.

Disco.

AnswerID: 470837

Follow Up By: Member - MUZBRY(Vic) - Thursday, Nov 24, 2011 at 21:09

Thursday, Nov 24, 2011 at 21:09

Scuse me Disco
His mate could be a mil spec welder or better .

Muzbry
Great place to be Mt Blue Rag 27/12/2012

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Follow Up By: ross - Thursday, Nov 24, 2011 at 23:59

Thursday, Nov 24, 2011 at 23:59

The welder is a qualified boilermaker and has done jobs for me before which I was extremely happy with.

My landcruser is tongue is a permanently fixed affair .It would be easier to cut and reweld the landcruiser toungue but I woulld prefer to alter the trailer as cutting and rewelding would make the drawbar straight all the way to the hitch.It currently has a"drop" in it.
Im not too much worried about the commodore for towing,I only tried it out today to see how it towed at that angle.

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Follow Up By: Nomadic Navara - Friday, Nov 25, 2011 at 00:29

Friday, Nov 25, 2011 at 00:29

Does your welder mate have the where with all to get the modifications approved? Does he know the specifications for towbars?

PeterD
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Follow Up By: ross - Friday, Nov 25, 2011 at 09:36

Friday, Nov 25, 2011 at 09:36

Im not modifying the towbar,Im going to modify the trailer.
It was custom built in 1984 and no one knows what it looked like when new.
I suspect I will be taking it back to how it originally looked.

Ive never known anyone to go and get the welding approved on a drawbar in WA.
Neat welds speak for themselves

FollowupID: 745393

Reply By: Dust-Devil - Thursday, Nov 24, 2011 at 21:38

Thursday, Nov 24, 2011 at 21:38

Why not just give the trailer a 'spring over' and whilst doing so, change the spring packs for ones with an extra leaf or three.

DD

AnswerID: 470845

Follow Up By: Dust-Devil - Thursday, Nov 24, 2011 at 22:06

Thursday, Nov 24, 2011 at 22:06

Ooops! just came to mind that the axle design on your trailer may preclude you from doing that.

If it was me doing something about your predicament I would most probably change the axles for solid 50mm with parallel bearings and matching hubs in the first instance (raises your trailer Mass chitloads) and allows for the use of matching vehicle wheels (always a plus re spares etc) plus greater ground clearance.

And the other option above re an adjustable height hitch always helps.

Another thing to check to ensure better towing behavior is that your trailer has some 'ball weight' i.e. the load is slightly forward of the balance point when unhitched requiring a jockey wheel to support it and get it onto the vehicle.

To enter a dialogue re the intricacies of the subject of 'ball weight' on this forum, is akin to pouring a bucket of petrol over ones self and lighting a match. So other than to say it is a major factor in successful towing of trailers and/or caravans I'll leave it at that.

What I will say though is that by utilizing the axle upgrade raising of the allowable trailer mass, you could put a very nice custom made storage box across the draw bars of the trailer, in which you could store your fridge on a roll out system etc etc. This would have the effect of moving some weight forward of the aforementioned balance point.

You may even be able to do this without the axle upgrade. Just a bit of 'food' for your thoughts.

Regards

DD

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Follow Up By: ross - Friday, Nov 25, 2011 at 00:08

Friday, Nov 25, 2011 at 00:08

Suspension works great as it is and Im firm believer in "if its not f@#$,dont touch it".
Its not for offroad purposes,I plan to put the box on the ute when I want to go offroad.

The alloy box already has a fridge slide(80 litre weaco) ,AGM 100a battery and Outback Camper Deluxe camper and kitchen,I dont really need anymore space.If I do it can go in the ute,under the canvas

I know about the ball weights and the debates it causes,iwhich is why I didnt mention it. ;)
It feels ok when I tow it,loaded or unloaded ,so I think I will level the hitch and towball off at the same height as the commodore

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Follow Up By: Dust-Devil - Friday, Nov 25, 2011 at 01:49

Friday, Nov 25, 2011 at 01:49

Sounds like a plan and gGood luck with all

FollowupID: 745381

Reply By: Member - Michael P (QLD) - Thursday, Nov 24, 2011 at 22:24

Thursday, Nov 24, 2011 at 22:24

Optimum Trailer angle?

Level !

AnswerID: 470853

Follow Up By: ross - Friday, Nov 25, 2011 at 00:48

Friday, Nov 25, 2011 at 00:48

Thanks,Ive found some sites with pics and explanations

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Reply By: The Bantam - Friday, Nov 25, 2011 at 13:43

Friday, Nov 25, 2011 at 13:43

The optimum trailer angle is such that the line of the chasis of the trailer is slightly down at the front.....level may be tolerable but never up at the front.

the thinking is thus.

under brakes, if the chasis is pointing up at the front the weight tranasfer will tendancy to push the rear of the tow vehicle up..in extreeme situations this will lift weight off the rear of the tow vehicle considerably compromising its stability....there are some compounding factors with this occurance.

With the plane of the chasis level or better pointing slightly (SLIGHTLY) down, the force will tend to be far more directly forward and if anything slightly down.

If the trailer is set up well, regardless of drawbar weight or distributing hitches the whole rig will behave predictably
.
This slightly down at the front situation is far far better than pointing up as there are a number of compounding factors that tend to help stability this way.

I have discused only braking which is the most predominant issue, acceleration and sway stability are all affected badly by an upward pointing attitude.

Remember there is a standard range for the nominal height of trailer couplings.

If the towbar on the landcruser is not a hitch reciever type, it will not be rated anywhere near the towing capacity of the vehicle.

I seem to remember the point is 1.2 tonnes or near.......anything over that has to be a hitch reciever type tow bar if it is fitted to a pasenger car or light commercial.

If you have a hitch reciever towbar, there are all sorts of hitches that can be pluged in at will to solve these problems.

cheers

AnswerID: 470906

Reply By: vk1dx - Friday, Nov 25, 2011 at 15:49

Friday, Nov 25, 2011 at 15:49

We purchased two tongues when we had the van. One for the van and one for the trailer.

Where are you? I don't use either now. Don't tow anything. However they are NOT hayman reese styles.

Phil

AnswerID: 470919