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Friday, April 9, 2021

More on quad vs dual brake system for MTB

Wheels of Happiness

Rizal Philippines
4.09.2021

Remembering the fall of Bataan.    (Reminds us that we should not give up Philippine territories - which we are doing without putting up a fight)

More on quad piston brakes:

1.  Marginal gains can be achieved of only 10%;

2.  We base on the surface area of brake pads, the  difference between the dual and quad brake piston is roughly 1 cm only.  Since we base the brake torque on surface area, surely gains can be marginal.






3.  The formula for calculating brake force (torque)

    Calculate the torque that the force of the road causes about the axle. Because torque equals force times its distance from the point of rotation, the torque equals the force of the road times the radius of the wheel. The force of the road is the equal and opposite torsional reaction caused by the brakes, so the braking torque is equal in magnitude and opposite in direction to the torque exerted by the road. If the Jeep's wheel has a radius of 0.25 meters, the braking torque equals 8,000 N * 0.25 m, or 2,000 Newton-meters.

Let us assume we need a force of 1,000 nM to stop the bike:

       For   160 mm.   R =  80 mm     .08 meter   =    80 nM

       For    180 mm   R=   90 mm      09 meter   =    90 nM

       For    203 mm   R = 101.5        .10 meter   =  100 nM

Unless we can show we are increasing the  force being applied (unless the brake lever increases in size, then the force is seen to be constant.    The pad force would be constant unless the area of the piston has increased.  

     

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