STABILISERS

[Lutz]

Hi Mike,

Interesting comment which I guess could be true for a post 2000 caravan.

OK, about 50%!. No, I do not tow with HGV. I tow with a 2005 Jeep Grand Cherokee Overland 2.7 ltr diesel with a gross vehicle weight of 2506 kg and kerb weight of 2235 kg. The caravan weight is 950 kg and the maximum laden weight is 1200 kg. It has a body length of 17ft 6 ins and an overall length of 20ft 6ins which by today's standards is probably short for a twin axel van. You are right in that the stabiliser has (fortunately) little to do horizontally but is useful to dampen pitching on minor roads.

The weight of the caravan is the reason for my comment regarding the difficulty in finding a replacement caravan as today's twin axel vans seem to be much heavier and longer.

Best wishes for happy caravaning and safe towing.

David

I think you may be surprised how stable modern single axled caravans are. The second axle is an awful lot of extra deadweight to tow around so if one can by with a single axle, so much the better. The caravan manufacturers seem to be thinking along those lines, too, as there are now already several 1800kg single axles on the market.

With all technical improvements being made and market demands for ever more luxurious caravans, coupled with the high cost of motoring forcing people to tow with smaller cars, I am sure that we shall see a general trend towards higher weight ratios in the future. I predict that 95-100% weight ratios will be commonplace within the next 10 years.

 

[ProfJohnL]

Hi John,

Exactly as you stated, the University of Bath research report clearly shows that a resistance stabiliser increases the zero stability speed - the speed at which the car and caravan are tipped on the point between positive stabilaity and instability.

But it is also clear the stabiliser device continues to operate in a perfectly linear way above that speed, so your conjecture that the car and caravan would suddenly become unstable - like a spring that snaps - is wrong.

The beneficial effect of the stabiliser is to increase the zero stability speed to way above the UK maximum speed limit for caravans, and better yet, for people towing at acceptable and legal speeds - the car and caravan are better able to resist external effects - like side-winds or passing trucks.

Bath Uni quoted an improvement of 15% in these areas - which was much more than the improvement from correct nose-weight loading of the caravan - which they tested from the legal minimum to maximum nose-weight - and achieved a measured 5% increase in stability.

I certainly agree that optimising our use of safety devices, correct loading, and sensible driving are additive - every thing that we do to improve safety is beneficial.

Can't agree with George's comments that modern safety devices (like a stabiliser) contribute to caravan accidents. This has the logical conclusion that we'd all be safer if the car air bag was replaced by a 10" steel spike.

Robert

Hello Rob,

I have ttied to find the Uni.of Bath research papers without success, can you give a a full WWW address?