Is there any real gain in a pedal bias box, or will a proportioning valve do the same job for a lot less money?

Hi there

For road use, a proportioning valve is just as good. Some benefit in competition to get the best set up and maximum braking for both wet and dry.

That said the adjustable bias pedals do look good!

Cheers

Ian

spot on advice

and a cheap source of proportioning valves is old fiesta's. They screw into the master cyclinder.

Is that a proportioning valve or a residual pressure valve?

(I don't know, that's not a loaded question!)

The way I read it, it's a pressure limiting valve to the rear circuit.

Marcus

Mondeo one is better bet --- higher pressure setting than the Fiesta

The ones off cars are not adjustable though,R they

A bias box will give you the correct front rear bias for one set of conditions, ie the wet or dry. If you go from a grippy surface to a slick surface then you would have to alter the bias for each surface.

The proportioning valve (as sold by AP) will allow the correct bias for all road conditions. The amount it limits is proportionate to the line pressure. At low line pressures it does not limit but at high line pressures it does.

At low grip you brake less hard so there is less weight transfer so you need more braking to the rear, on ice it would be close to 50-50. On very grippy tarmac it could be closer to 90% front and 10% rear.

So ideally you need both a bias box or proportioning valve.

John

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Originally posted by gjs
The ones off cars are not adjustable though,R they

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