Text 26503, 53 rader
Skriven 2009-01-20 13:12:24 av Michiel van der Vlist (2:280/5555)
     Kommentar till en text av Björn Felten (2:203/2)
Ärende: The shoe chucker
========================
Hello Björn,

On Tuesday January 20 2009 11:40, you wrote to me:

 BF>    And I can understand that having a house pushing on the car can be
 BF> a real challenge, even if they have (drum?) brakes of their own.
 BF> Up-hill too can be rather challenging, I can imagine...

Uphill is a bit of a challenge but not as much as it would seem at first hand.
Just gear down and push the accelerator. Slopes up to 10% are no problem, above
that it can be a bit hairy if one is forced to stop. Such as when there is a
traffic jam. In Switserland uphill traffic has right of way.

Downhill is where the real problem is. Trailers with a maximum loaded mass over
750 kg or over half the mass of the (empty) tractor are required to have brakes
of their own. 99.9% of the recreational trailers are in that category.

I have never seen a trailer with disc brakes, they all have drum brakes. As the
speed of combinations is limited in nearly all countries between 80 and 100
kph, this is good enough... Except in the high mountains.

The only officially allowed system for trailers behind passenger cars is the
push brake system. When the car decelerates, the inertia of the trailer makes
it push against the car and that activates the brake. It is a pureley
mechanical system. Very reliable and it works with every trailer and every car
combination. The only problem is that it automativally activates when going
downhill on contstant speed. Even if you never touch the brakes and do it all
with the engine, the trailer brakes will still activate when going downhill. In
the high mountains, this is a sure recipe for overheating the brakes.

Several systems to prevent this have been proposed and been experimented with
but so far none of these have been found safe enough to replace the classic
push brake system. (I do not know if that is the right word, in Dutch we call
it "oplooprem".)

So far the only way is to stop at regular intervals, check the brakes of the
trailer and let them cool off if needed.

To help me, I have installed a light that flashes whenever the trailer brakes
are activated. It also doubles as a warning that the parking brake of the
trailer is on.


http://www.vlist.eu/mistlamp/index4.htm

Sorry, it is in Dutch..



Cheers, Michiel

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