Brake master cylinder ratio info

[THE STUFF 187]

Thought this might be helpful to some of you.


While reading a post on a Ducati forum noting issues with using Panigale (1199) calipers with other master cylinders; I came upon the following general info. concerning MC vs. Caliper sizing. Enjoy!

When you design a hydraulic system it's important to have good feedback from the lever as to how much lever force to apply to achieve a desired braking rate. Having good feel, sensitivity and control is the major factor influencing braking quality.

The main factor in designing good braking modulation characteristics is the ratio of the total area of the caliper pistons to the area of the master cylinder.

The Panigale calipers have a total piston area of 5655 sq. mm and has a master cylinder area of 201 sq. mm. This gives a hydraulic ratio of 5655/201 = 28.1.

The RCS brake master cylinder has an area of 284 sq. mm. Used with the Panigale calipers you get an hydraulic ratio of 5655/284 = 19.9.

A general design rule-of-thumb for twin rotor brake systems is as follows:

30:1 - soft feel
27:1 - sweet spot for design
23:1 - firm feel
20:1 - wooden feel

http://forums.13x.com/attachment.php...3&d=1350328035


Thank you,
Justin Torres

Owner of

Adrenaline cycle

2595 GAR Highway

Swansea, MA 02777

Phone. 1-508-379-0100

Fax. 1-508-379-0113

Web. Adrenalinecycleinc.com

&

Adrenalinecycleinc.net

[Kurlon]

Note, there is more to it than just ratios. Rotor diameter, rotor count and radial vs traditional pumps alter the target ratio ranges.

[Eric Baker]

As well as lever ratio. Good little chart though.

[THE STUFF 187]

These #'s are all for radial caliper newer bikes, which have a very similer braking systems. I have swapped 19x18 & 19x20 brembo masters on the same bike. The brake lever feel was so much different between the two. This gave me a better understanding of how my brake lever would feel after making any changes. Just thought it was interesting & helpful

[Paul_E_D]

So, if i have a wooden feel at the lever, do i go smaller at rhe mc?

[The Snowman]

So, if i have a wooden feel at the lever, do i go smaller at rhe mc?

No, you get a stiffy.

[THE STUFF 187]

You would go with a smaller master cylinder with less overall area or calipers with smaller pistons with less area

[wiggeywackyo]

Actually, you want smaller master cylinder or larger pistoned calipers.

[THE STUFF 187]

you are correct my typo

[Paul_E_D]

OK, but to throw things off, I would be going from a regular coffin type MC to a radial... I guess I just have to try one and see.

[SVRACER01]

OK, but to throw things off, I would be going from a regular coffin type MC to a radial... I guess I just have to try one and see.

im thinking of doing the same on my KTM

[Paul_E_D]

I guess there's a brembo 18 x 20 that is supposed to work well. I just don't know what the hell the #s mean. lol

[csmutty]

I guess there's a brembo 18 x 20 that is supposed to work well. I just don't know what the hell the #s mean. lol

Paul, I used a 16x18 brembo radial on my motard with the 4 piston motomaster caliper and it worked awesome. It wasn't overly stiff and it provided great feel.