Does the Cerbera have a brake bias valve?

[Brummmie]

Cant remember seeing one, but is it integral somewhere? Just thinking on trackdays etc it would be nice to have more control of its braking behavior.

[ff5317]

Mine has, but it's defo not an original fitment.

[Ireland]

I haven't seen one anywhere on mine.

[trackcar]

ff5317 said:

Mine has, but it's defo not an original fitment.

There can't be many 5 litre cerberas about so I reckon it's probably one that i've fitted.

[Brummmie]

trackcar said:

ff5317 said:

Mine has, but it's defo not an original fitment.

There can't be many 5 litre cerberas about so I reckon it's probably one that i've fitted.

So Jules...does that mean they do not have one as OE, even one that is built into the brake system anywhere? Cheers Brum.

[brogenville]

the workshop manual states that there isn't a brake bias valve- it's all just preset based on piston areas etc

[brogenville]

the workshop manual states that there isn't a brake bias valve- it's all just preset based on piston areas etc

[GreenV8S]

brogenville said:

the workshop manual states that there isn't a brake bias valve- it's all just preset based on piston areas etc

That can't be right.

[Brummmie]

GreenV8S said:

brogenville said:

the workshop manual states that there isn't a brake bias valve- it's all just preset based on piston areas etc

That can't be right.

So you think there must be?

[GreenV8S]

Brummmie said:

So you think there must be?

I know TVR have produced some pretty bizarre brake setups over the years but I would like to think even they would stop short of selling a car without a bias valve. It is physically impossible to balance the brakes properly without one and it's hard to see how they would ever have got it through type approval like that.

[JonnyW]

I don't have one and the car is stripped bare! I run six pots on the front and standard on the back, all vented though and I outbrake most Porsches and Ferraris! Don't bother!!

[GreenV8S]

JonnyW said:

I don't have one

So are your brakes balanced right for hard braking, or light braking? They can't be right for both.

[longbow]

There is no bias valve as standard - as previously mentioned the bias relies on piston size and disc area, so changing the front for bigger discs etc will move the bias forward.

[Byker28i]

GreenV8S said:

JonnyW said:

I don't have one

So are your brakes balanced right for hard braking, or light braking? They can't be right for both.

erm - don't understand this. The only time we ever changed brake balence in the race caterham was on wet setup, to put more braking to the rear.

[GreenV8S]

Byker28i said:

erm - don't understand this. The only time we ever changed brake balence in the race caterham was on wet setup, to put more braking to the rear.

The mechanical / hydraulic leverages determine the ratio of braking front/rear under very light braking. Usually this is set up to more or less match the static weight distribution. As you apply the brakes more heavily weight is transferred forward so the ratio of front/rear braking needs to change. The theoretically ideal relationship is a curve that has the rear braking effort tapering off (relative to the front) as you brake harder and harder.

If you rely on the static brake distribution only, then you have no way of compensating for weight transfer. This means you have to decide whether you are going to set your brakes up to be correctly balanced under light braking, or heavy braking. It cannot be right for both. If you set it up so it is right for hard braking then under light braking you will have too much effort at the rear. If you set it up so it is right for light braking then under heavy braking you will have too much effort at the front.

For a racer where you know in advance what the conditions are going to be, don't know enough (or can't afford to spend the time) setting the brake balance up properly, or just have more important things to concentrate on, that's fine. But for a road car the balance needs to be right all the time and you can't expect the driver to be fiddling with valves and so on as they're slithering around the roundabout trying to avoid that HGV.

[trackcar]

Most cerbs I have worked on do have a small limiter built into the rear line .. it's a cylinder screwed into the rear Tee piece that splits the single rear line into two to goto each rear caliper. I dont know how it works as ive never had one apart, but you can see its action when you test the rear footbrake at MOT time .. the line pressure is limited so there's only so much rear effort you can generate no mater how much pressure you put on the pedal.

Edited by trackcar on Saturday 11th October 21:02

[Brummmie]

trackcar said:

Most cerbs I have worked on do have a small limiter built into the rear line .. it's a cylinder screwed into the rear Tee piece that splits the single rear line into two to goto each rear caliper. I dont know how it works as ive never had one apart, but you can see its action when you test the rear footbrake at MOT time .. the line pressure is limited so there's only so much rear effort you can generate no mater how much pressure you put on the pedal.

Edited by trackcar on Saturday 11th October 21:02

I know exactly where you mean, so eliminating this and then installing an independent control would give me more control. However if this is just a restriction as opposed to a controlling valve then all it does is take initial "snatch" out of brake application?

[TT Tim]

Not sure about a bias valve, but a line lock looks like a lot of fun!

Lock brakes at 1:15, car full of smoke by 1:28

http://www.youtube.com/watch?v=sUWy2yOYLxI

Would be a great way to warm tyres on a sprint.

Tim

Edited by TT Tim on Saturday 11th October 21:57