Brake Bias

[Exige77]

Can someone please explain how different brake master cylinders can give a different brake balance between front and back ?

Many thanks

Ex77

[Mr Sparkle]

I thought you would usually use a balance bar or proportioning valve to do this. But as I understand a larger cylinder will displace more hydraulic fluid but at a cost of greater force required for the same pedal travel.

Do you have a specific problem you are trying to solve?

[Exige77]

Just fitted an AP Motorsport master cylinder which is supposed to move the brake bias to the back. You need to use this in conjunction with a bake bias valve which I have so you can move it slightly forward again to achieve the desired balance.

I would like to understand how the single master cylinder sends more torque to front or back ? How is the force distributed ?

Thanks

Ex77

[Nick1point9]

Different area pistons for front and rear circuit will generate different pressures.

[Nick1point9]

Repost, stupid phone.

[Exige77]

Nick1point9 said:

Different area pistons for front and rear circuit will generate different pressures.

Think the bore is the same throughout its length.

Ex77

[Nick1point9]

The bore will be the same but there will be a rod/shaft running the length of the cylinder and by changing it's diameter you change the area of the piston.

[one eyed mick]

EH!!!!!!!

[Evoluzione]

1. Ring AP, it's their product.

2. Report back here and put us out of our misery.


In the past I have found them to be very knowledgeable, helpful and forthcoming with information about their own products, including even sending me working drawings.

[Mark_r33]

The original cylinder doesn't have a bias valve built in, does it?

Never seen a Lotus one, but Chapman always liked simplicity, and having everything in the cylinder may, perhaps, be described as that!

[Kozy]

Is it a tandem cylinder, with a diagonal split circuit?

If so, I'm not sure the cylinder will have any effect on bias.

You normally need twin cylinders for that. The smaller the cylinder, the more pressure it supplies, the more brake force the axle it feeds delivers.

[FrogPower]

Exige77 said:

Can someone please explain how different brake master cylinders can give a different brake balance between front and back ?

Many thanks

Ex77

By having differential bore sizes/swept volumes within the respective areas that feed front/rear lines, but they aren't very common as a standard fitment, it's easier to manage bias with calipers or bias valves. (FYI - Porsche 944 master cylinder has different cylinder bores)

Edited by FrogPower on Tuesday 25th June 20:54