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How Effective Are Stabilisers?


Desperado

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A couple of weeks ago I went down to Cheddar for a long weekend.

 

Following un hitching my van one of the side friction clamps on my ALKO 2004 stabiliser fell onto the floor.

 

On close inspection the circular pad had broken away from the pin that holds it into place.

 

I was a little concerned on my return trip back up the M5 that the caravan would be prone to swaying as I was now without an effective stabiliser.

 

I was relived to find I felt no difference to the stability of the rig so it got me thinking how effective they really are.

 

Can a few square millimetres of plastic clamped to a metal tow ball prevent 1500kg of caravan from swaying?

 

I have since bought a replacement for the broken part so I’m not fully convinced in my argument, however I will be interested to here

 

from any engineers out there on their thoughts.

 

Desperado

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As laymen we can't actually demonstrate the effectiveness of stabilisers.

 

A sensibly loaded caravan towed by an appropriate vehicle in normal conditions should be inherently stable. So none of us should notice a difference, on or off, in normal circumstances and none of us would deliberately put ourselves in an extreme situation willingly.

 

I'd suggest that any caravanner who can detect a difference on his own outfit between stabiliser on or off is either towing an inherently unstable outfit or has the talent to eclipse Michael Schumacher!

 

It's a bit like ABS brakes - careful drivers never normally get it to function but it comes in very handy in unexpected emergencies.

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As Roger says - the stabilizer should not be required in normal use - but only in exceptional circumstances. Ie: when the heavy goods vehicle passes too close to the van When you exceed a sensible speed on a downward slope. Or the van meets a sudden crosswind. Regard your stabilizer as the tightrope-walker regards his safety net. Only there for emergency use.

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The only time I have noticed any difference is when I reversed with the stabilizer on. Its much easier to reverse with the stabilizer off!!

 

Even easier with a caravan mover.

 

 

Pete

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I agree with Roger and John, never had a stabilizer until we bought one with an alko fitted, the only time I feel the effect is from a sudden cross wind!!

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If you have no stabiliser you'll know when a HGV overtakes you then you'll realise how important they are or when you overtake an HGV or other large vehicle. Their effectiveness should not be under rated. They are not really just there for emergencies, they work 100% of the time whilst you are towing. I agree that sensible loading of the car and caravan to within agreed specs goes a long way to providing a stable outfit. The stabiliser gives you that extra comfort, extra re-assurance that whatever the circumstancesyou are as stable as you can be.

 

navigator

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I feel an uncommon urge to agree fully with Roger!!! and others for that matter. ..these are there for the exceptional moments not the ordinary.

 

Speaking of the exceptional Desperado. ..did you stop at the new CC site in Cheddar?

I only ask as I wonder how the warden 'Lou' is doing??

gary1s.gif

 

Arc Systems are specialist Carver caravan product repairers, committed to providing a comprehensive service as well as spare parts for these popular heaters.

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Unlike other safety systems which only opertate in an emergency or over zealous use of something, stabilisers are working all of the time, most of which you could say they were not needed to control stability in a well balanced outfit so we don't really know at what points they have 'usefully' kicked in and out so to speak.

 

Wonder if you are any better off at all with one fitted say in a tyre deflation situation?

 

Something that I can't rationalise is the relative effectiveness of say the Scott design where you have something a bit more like a small car clutch as opposed to the AL-KO, which grips around a ball of much smaller diameter and area.

 

Griff.

Stay safe - Griff.  :ph34r:

Wheels at the front Green Oval Towing Machine

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Something that I can't rationalise is the relative effectiveness of say the Scott design where you have something a bit more like a small car clutch as opposed to the AL-KO, which grips around a ball of much smaller diameter and area.

Griff.

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The side arm stabilisers give lateral damping through the friction discs, and longitudinal damping via the spring arm or rubber in compression. They are able to reduce both swaying and pitching. They also offer a degree of levelling, by causing a small transfer of weight from the rear to the front axle of the towcar, whilst at the same time increasing the down force on the tow ball.

 

The friction hitch design is most effective in reducing side movements (sway) since the pads slide around the tow-ball, but have less effect on reducing pitching since the pads simply rotate on one spot of the tow-ball. The full trailer noseweight has to be supported by the rear axle of the towcar.

 

Make sense?

Gordon.

Fourwinds Hurricane 31D Motorhome. Also MGTF135 1. 8i Roadster (fun) & Volvo V70 3.2Ltr LPG (everyday car)
Unless otherwise stated, my posts will be my personal thoughts and have the same standing as any other member of Caravan and Motorhome Talk.

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The side arm stabilisers give lateral damping through the friction discs, and longitudinal damping via the spring arm or rubber in compression. They are able to reduce both swaying and pitching. They also offer a degree of levelling, by causing a small transfer of weight from the rear to the front axle of the towcar, whilst at the same time increasing the down force on the tow ball.

 

The friction hitch design is most effective in reducing side movements (sway) since the pads slide around the tow-ball, but have less effect on reducing pitching since the pads simply rotate on one spot of the tow-ball. The full trailer noseweight has to be supported by the rear axle of the towcar.

 

Make sense?

Gordon.

41822[/snapback]

 

Gordon

 

How, exactly does a blade stabiliser reduce pitching? The 'spring effect' is only in one direction. The only friction damping I can perceive is as the blade slides through the caravan bracket and this is designed to reduce friction - not increase it. I am not convinced that it reduces noseweight by any degree. Explanations please.

 

Mike

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Gordon

 

How, exactly does a blade stabiliser reduce pitching?  The 'spring effect' is only in one direction.   The only friction damping I can perceive is as the blade slides through the caravan bracket and this is designed to reduce friction - not increase it.   I am not convinced that it reduces noseweight by any  degree.   Explanations please.

 

Mike

41894[/snapback]

 

I think Gordon's spot on Mike, and a spring must act in both directions. .."for every action theres a reaction", it's nothing to do with the blade sliding that's simply there for cornering. The Friction he speaks of is in the pads but that's against sway.

However this tranfer of weight at least permanantly is open to debate?, I tend to think it's akin to standing in two buckets and trying to pick yourself up but during actual pitching it has to have something of this effect.

Having said that, I have always believed an Alko type hitch could not out do a blade type for effectiveness, it's just a darn sight easier and cleaner to use.

gary1s.gif

 

Arc Systems are specialist Carver caravan product repairers, committed to providing a comprehensive service as well as spare parts for these popular heaters.

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Gordon

 

How, exactly does a blade stabiliser reduce pitching?  The 'spring effect' is only in one direction.   The only friction damping I can perceive is as the blade slides through the caravan bracket and this is designed to reduce friction - not increase it.   I am not convinced that it reduces noseweight by any  degree.   Explanations please.

 

Mike

41894[/snapback]

 

Mike.

 

I agree with Gordon and Gary.

 

Here's the earlier thread on exactly the same subject with a quotation from Hobbybod explaining the principle.

 

http://www. caravantalk. org. uk/forums/index. ..wtopic=2039&hl=

 

Frank

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Guest Hobbybod
Mike.

 

I agree with Gordon and Gary.

 

Here's the earlier thread on exactly the same subject with a quotation from Hobbybod explaining the principle.

 

http://www. caravantalk. org. uk/forums/index. ..wtopic=2039&hl=

 

Frank

41902[/snapback]

Thanks for the 'quote' Frank. I've posted about stabilizers on so many threads in various forums I forget what I've posted where!!

 

But this posting mentions most of the salient points pertinent to the discussion here.

 

Somewhere?, I have posted a piece about the dynamics of stabilizers, particularly the blade type, and also the German electronic stabilizer systems (works through the caravan's brakes) called LEAS. see here and a similar one by Reich.

 

Suffice to say that with a correctly towed, well balanced outfit you'll never notice the stabilizer, UNTIL some 'emergency' happens. And then boy are you glad it's there.

 

This has happened to me on just two occasions;

1) With the double blade Tunesi Stab 330 stabilizer.

Going down hill (~50mph) on a left-hand bend on a N road in France, a doddering froggie decides to exit his field in his 2CV without looking at all. So I have to do an emergency stop, on a bend, downhill, to avoid hitting him. The outfit behaved impeccably with not the slightest hint of jack-knifing. I shudder to think what might have happened in such circumstances towing 'unstabilized'.

 

2) With the Winterhoff on the Hobby.

I have posted this before but can't find the thread!

Towing on the inside lane of the M25 (near to jcn27ish) at ~60mph. I see in my mirror I'm being overtaken by an old (high floor pan) LHD Jeep Cherokee.

This jeep driver seemed totally unaware of my car and pulled over right in front of it, whether through ignorance, or deliberately, I don't know!

I had to swerve into the emergency lane to avoid an accident.

This swerve initiated a violent snake; I backed off the accelerator, only momentarily braked and 'locked' my arms on the steering wheel, keeping the steering wheel as still as I could. After 3 large oscillations the 'van steadied down and I carefully went back into lane 1.

Heart was going 19 to the dozen!

 

Again, I would not like to do that 'unstabilized'!

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