Para 37


Peter W Jones MInstP.

Photograph of Stabiliser and Tow Ball

Below is a photograph of the  same stabiliser that I published on >


March 9th.


This time I have removed the tow ball cover so that the size of the


 tow ball relative to the circular part of the stabiliser can be


.seen.The tow ball is a standard 50mm in diameter.

Inside the circular part of the stabiliser are TWO friction pads of
100mm diameter, with a circular space in the centre of 50mm

diameter where there is no friction material.

Readers who have remembered their GCSE Maths will be able to calculate the area of the friction material available in my now obsolete Scott stabiliser ( but similar stabilisers are still on sale) and compare that with the area of friction material available inside the ALKO stabiliser which is still on sale as a “retro fit” and as a standard item on most of the used caravans in dealers’ show spaces.

However, do not give up if you lack a GCSE Maths textbook because the difference in size between the area of friction available with the Scott Stabiliser and the ALKO stabiliser is so great that it is apparent from my photograph below and it is hardly worth doing the calculations.

For readers who are not familiar with ALKO stabilisers I must point out that this device uses friction between a tow ball free from grease and a “cup like” device which fits over the tow ball.

The force of friction generated by your cars’ brakes is not only in direct proportion to the area of your discs (on the brakes), but in direct proportion to the force applied to the brake pedal (this is of course not quite true if you have abs or a similar electronic system.)

My Scott stabiliser has a nut which can clearly be seen in the photograph and this is used to take up wear and keep the correct force on the friction plates. To the best of my knowledge the only way that owners of the ALKO friction based stabiliser can allow for wear on the friction pads is to replace them.

If ALKO engineers had viewed the matter in the above light they would not have made this type of stabiliser as it is clearly inferior to the type it has now managed to almost completely replace. I would give the ALKO device full marks for smartness of design and appearance, but very low marks for effectiveness in reducing snaking of trailers/caravans with over run brakes.

Details of my test for friction based stabilisers are in Section 18a.They are also further on in this blog (or in the archives). The duplication is due to the fact that seems to be “off line” a great deal of late.




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