Friday, Feb 15, 2013 at 14:38
There is a very good reason whey we have brakes on all wheels on driven vehicles that has to do with handling and controll,
If a driven vehicle relied on only front brakes, it would understeer in may situations of heavy braking and oversteer in others.....if reliant on rear brakes only it would also oversteer under heavy brakes and the braking would be compromised due to forward weight transfer.
In short driven vehicles would be far far less safe with brakes on only 1 axle.
Trailers only follow and on close grouped axles there is not the consiquence of weight transfer or oversteer there is is a driven vehicle
In heavy vehicles the load is directly related to the number of axles..typically 6 tonnes on a single wheel axle and 9 tonnes on a dual wheel axle.....to have sufficient braking power for the load carried brakes are required on each axle.
On light trailers it is possible to fit brakes that have far more braking power than required to stop the mass capable of being borne by the single axle or the pair of wheels fitted to it will bear.
For example a typical pair of 10" x 2 " electric drums will stop at least 2 tonnes may be 3.......but it is very common to step to dual axles over 1.5 tonnes and lots of 2 tonne trailer have dual axles.
If stepping to tripple axles it would be entirly workable and safe to have brakes on only the front 2 axles for a 3.5 tonne trailer.
Its far from silly.
As for the ADRs and rear wheel carriers.
If you sit down a rear ADR specifications for the various lights and the angles which they are required to be viewed, you will see why it is plain and clear why extra lights are required for fitting a lot of certain spare wheel carriers and bullbars.
There is a very good reason for everything in the ADRs.....but there are plenty out there without the willingness to understand.
If you realy want to know...it helps to actually go an read the ADRs...then read the explanatory statements and other supporting documents
cheers
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