Towing Hitch Height Adjustment

Submitted: Wednesday, Aug 04, 2004 at 09:48
ThreadID: 15285 Views:3438 Replies:3 FollowUps:3
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Looking for some advice or "tricks" about adjusting the height of my towing hitch.
I have a Hayman Reese Weight Distribution Hitch which I use with a Treg Coupling on a Coromal Seaka 505 dirt road caravan.
I have just had heavier springs and Bilstein shocks fitted to my 4wd. This has lifted the back of the car about 50 mm. I estimate the ball weight to be between 150 to 180 kg.
Do I now adjust the height of the hitch so that it is the same as the caravan when the draw bar is parallel to the ground (unhitched) or is it better to set it a little higher so that when the weight goes onto the car the van returns to a parallel position.
Or is it a matter of trial and error. ie hitch the van and install the torsion bars and then do an eyeball on the rig? Adjust if necessary.
Alll comment gratefully received.
Thanks

Rosscoe
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Reply By: MrBitchi - Wednesday, Aug 04, 2004 at 10:19

Wednesday, Aug 04, 2004 at 10:19
Rosscoe,
You should aim for being level when fully loaded and hitched up. It really is trial and error but as long as you don't have too much weight on the towball your torsion bars should take care of it. With the heavier springs you should get less sag than before to start with.
John
AnswerID: 71223

Follow Up By: Rosscoe - Wednesday, Aug 04, 2004 at 10:31

Wednesday, Aug 04, 2004 at 10:31
Thanks John,

I intend giving it a go on the weekend.

Rosscoe
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FollowupID: 331428

Reply By: duncs - Wednesday, Aug 04, 2004 at 10:36

Wednesday, Aug 04, 2004 at 10:36
Rosscoe,

When you adjust your coupling height be very careful not to have it too high.

I am not an expert about all the physics involved but I do know, from a rather scary experience that if you get it wrong the van will drive the car. I once loaded a box trailer with the aim of avoiding the back of the tow vehicle being too low. This meant that the weight was not evenly distributed ie too much at the rear of the trailer. This was OK until I was heading down a steep downhill with the right foot off the throttle, it dragged the car all over the road. If I baked it got worse and I was to scared to accelerate.

I know you are not talking about reducing your ball weight but simply having the coupling too high could have the same effect. For example if you are moving a loaded trailrer by hand it is easier to lift once the coupling gets above a certain height, usually horizontal. THis is because gravity allways pulls vertically down if the coupling is too high then the centre of mass is moved towards the rear of the trailer and this could casuse problems.

Like I say I'm not an expert buyt I do know how scary it is when the trailer takes over.

Duncs
AnswerID: 71229

Follow Up By: Rosscoe - Wednesday, Aug 04, 2004 at 10:59

Wednesday, Aug 04, 2004 at 10:59
Thanks Duncs,

Yes, I know what you are talking about.

I am aiming for a level rig. There's the separate issue of distributing the weight of the trailier. Rule of thumb says that ball weight must be between 10 and 15% of the total weight of the caravan. This means that you have sufficient downward force on the tow bar to maintain vehicle stability.

Fortuenately I've always had a very stable rig and with electric brakes which can be operated manually a quick touch on the manual without the foot brake will help to stabilise a wayward van

Regards,

Rosscoe
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FollowupID: 331433

Reply By: Gerry - Wednesday, Aug 04, 2004 at 10:51

Wednesday, Aug 04, 2004 at 10:51
Hi Rosscoe,
Full instructions on Hayman Reese website at www.haymanreese.com.au/consumer/products/wdh/WDH_Installation_Instructions.pdf

Cheers
Gerry
AnswerID: 71234

Follow Up By: Rosscoe - Wednesday, Aug 04, 2004 at 11:18

Wednesday, Aug 04, 2004 at 11:18
Ta gerry,

That's the "bee,s knees". Just what i was after.

Regards,

Rosscoe
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FollowupID: 331438

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