Brake Master Cylinder Lesson Needed

[Chriss]

Hi,

What's the difference between a radial master cylinder, and a... normal one? Secondly, when it comes to sizes, what does 16x18 etc mean? How would you choose the best one to suit your bike? Or is it just down to which ones fit the bike?

Massive thanks in advance.
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TheShaggyDA: I've got 3 or 4 pairs that predate my wife, so at least 11.5 years old.

[Wafer_Thin_Ham]

A normal M/C is mounted parallel to the lever, whereas a radial one is mounted 90 degrees to it.

16 x 18 or whatever is the ratio of the M/C. So how much it increases the force you put in at the lever end.

Some increase the force loads, but have very little feel, whereas other increase the force less but have more feel.

At least I think that's right.....

Radial:

https://www.superbiketoystore.com/sport/images/uploads/brembo-clt-mc.gif

Normal:

https://www.randakks.com/Nissin%20Master.jpg

See the difference?

I know AP Racing do an M/C with adjustable ratio, unsure how much it is though.
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[Chriss]

General rule of thumb = As power increases, feel decreases?
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TheShaggyDA: I've got 3 or 4 pairs that predate my wife, so at least 11.5 years old.

[Frost]

To some extent yes.
Often there are things that reduce both however, things like air in the brake lines, boiling fluid, weak hoses etc.

[MaybeGuy]

i always thought the 16x18 was bore size, not power ratio. and if 16:18 was the ratio, the bike wouldnt stop very well at all unless you had superman grip!

length x width.

some of them are different sizes for twin or single calipers as more fluid is required to move twins.

same with 4 or 6 pot calipers.

i THINK of the top of my head, 16x18 is best suited for 4 pot twin calipers. or so i read somewhere.
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Blue_SV650S wrote: it was a sh1te wheelie, but it proves that he can get it up in 3rd and can do angles. In summery, mattsprattuk is a gobby little sh1tebag, dopehead tw4t, but sadly for all of us, he probably isn't THAT full of sh1te!!
Kickstart wrote: Hi I tend to agree with Matt. All the best Keith

[Kickstart]

Hi

The numbers on a radial master cylinder refer to the 2 different things that affect the ratios. One is the master cylinder bore (so affects the hydraulic ratio between the master cylinder and the caliper pistons), the other is the distance from the lever pivot point to where it presses on the master cylinder (well, simplified it is).

In a perfect system (ie, no air, etc), more lever movement will give you the same braking force for less lever pressure. Similarly less movement will give you the same power for more lever pressure. More pressure tends to mean less feel.

Not sure there is any real basic difference in radial and non radial master cylinders, just that radial ones tend to use far larger pistons and a far smaller distances from the pivot point to the piston. Suspect that they just have a better choice of these ratios.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Fisty]

[Wafer_Thin_Ham]

[BanditsHigh]

[Kickstart]

Hi

The stroke is pretty much determined by the size of the caliper pistons. The ultimate stroke should (hopefully) never be an issue.

This might give you a few details:-

https://cyclebrakes.com/html/brembo_cylinders.html

Agree that the amount of fluid pumped is important. Put a master cylinder designed for a pair of 6 piston calipers onto a bike with a small single piston caliper and there would be negligable lever movement and stuff all feel.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing