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Old August 26th, 2018, 02:59 PM   #33
Mohawk
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Name: Chris
Location: Bristol, UK
Join Date: Feb 2016

Motorcycle(s): ZZR250, VFR800

Posts: 475
The most important thing is the M/C to pistons ratio. For a twin 4pot brake system the best power ratio is around 33/1. When you reduce this to a single 2 piston calliper, then the sweet spot ratio is around 8.5/1. A lower first number will make the lever feel stiffer & require MORE pull by your fingers for any given brake effect. A bigger first number will make the lever feel softer, but will result in an increased brake effect for less pull by your fingers, but a longer lever travel.

To work it out do the following.
Piston diameter divided by 2, times the answer, times 3.14 will give you the area of ONE piston be it brake or master cylinder.

So the stock Ninja front calliper has 2x27mm pistons & IIRC a 14mm M/C.
So calliper = 27/2=13.5, so 13.5x13.5x3.14 = 572.3mm2, as there are two pistons, we double this number (x2) to 1144.6mm2. This is the total piston area.

The M/C is 14/2 = 7, 7x7x3.14 = 154mm2. So if we devide the piston area by the M/C area we get a brake ratio of 7.43/1 which is on the stiff side of optimal.

Say we changed to a 12.7mm M/C then 1144.6 / 126= 9.04, which is on the soft side of optimal, but will produce a nicer feel & a more easily modulated brake.

So optimal woul be a 13mm M/C if you can find one.

YMMV

Last futzed with by Mohawk; August 26th, 2018 at 11:40 PM.
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