yamaha master cylinder

Randy Grein randygrein at comcast.net
Sun Jul 11 21:54:29 PDT 2010

Um, volume can be ignored, as it is piston area times displacement. Or  
you can use it as a measure of leverage...

The complete question is a bit more complex - it also involves the  
coefficient of friction between pad and rotor, caliper/line flex  
(which reduces effective pressure), and pad skew from wear. However at  
the MC end lever configuration has an effect, as it changes leverage -  
and throughout the stroke for standard master cylinders. None of this  
is terribly relevant though, as MC diameter is the primary determinant.

BTW Jim, the leverage ratio of the hand can be found precisely by  
summing the leverage and force applied by each finger. It doesn't  
matter all that much unless you're comparing large hand/small hand,  
but even then position will be far more important. When I switched  
from stock to the EBC kit pads I had so much more stopping power I had  
to move the lever position out (closer to the switch pod) to reduce  

Randy Grein

On Jul 11, 2010, at 1:04 PM, wmontoya at znet.com wrote:

>> Technically you're dealing with pressure. Pressure is force divided  
>> by
>> area(P = F/A)...
>> Leverage is largely an issue of lever length (or distance from axis  
>> of
>> rotation), and should be constant so long as your hand is at the same
>> spot...
>   "yes" on the former, "partly yes" on the latter... volume is also an
> important factor in the "lever throw" result, with the volume of fluid
> pushed from the MC into the caliper having a significant impact on  
> how far
> the lever needs to be pushed (e.g. how much fluid volume the caliper  
> needs
> to push the pad against the rotor).. ...  so a smaller diam. piston  
> for the
> MC will require less force at the lever AND a longer throw at the  
> lever,
> even w/ lever length held constant.
>   volume displaced/tranferred is the "other factor" that must be  
> considered
> such matters.
> regards...   WM

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