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Brakes and Physics.



Ok Folks...
I got tired of the argument. So I've whipped out the Physics book. Any
ME's out there or ppl

that are better at ACTUAL REAL non-Relativistic or mumbo jumbo my ass
tells me... physics

feel free to pop in.

Disclaimer... most things exemplified here are in normal braking
conditions. ie. you have not

done two footed driving for say 20 or 30 min. or heavy braking to get the
fluid near the

boiling point.

#1. The brake linings in our cars are better now then ever before. If you
brakes are turing

to shit. Go buy race or near compound brake linings. You have to replace
em more often, but

they do work and they make big messes. The race linings will behave more
like ideal friction

surfaces than most.

#2. There is nothing else at all in the system that can expand or
compress. Period. As the

volume of fluid gets reduced in container A it goes into the other
containers ie. your wheel

clynders.

Basic PHYSICS lesson. (yes im on my soapbox)
A vehicle moving has inertia. It takes the same amount of WORK to stop the
vehicle in a given

length. ie. F=ma
if you solve for a then it is a = F/m

the m is constant or very near constant as a small change of less than .1%
is not going to

make a difference in this calculation.
So that means that in order to get a larger negative acceleration a larger
F is required.

Assumption. Your tires are not crap. Your tires are relatively sticky. ie
they have a decent

coeffienct of friction and maximum force point before they turn to
dust/liquid/gas.

so now you are trying to increase the force to increase the negative
accleration. no mind you

were are still living in the linear force section of the friction curve.

(FORCE lesson)
IF the force applied to the disc is constant. the ONLY method for
increasing the torque

applied to the rotating mass is to increase the distance from the center.

If you want to increase the force in the exsisting caliper and disc you
basic choices are.
-- depress the pedal farther but past the point where the master clyn is
empty.
-- increase the lever arm of the pedal (less force by you.)
-- move a larger volume of fluid. ie a larger master clyn diameter and the
same bore length.
-- longer bore length (more pedal travel) same diameter
-- or a combination of increasing bore diameter or length.
-- this whole master clyn description basically boils down to more volume
in the master clyn

so now you know that to get more force with the same pads, calipers, and
discs it takes a

bigger master clyn to get more force.

What does increasing the size of the rotors/discs do?
by using the SAME size calipers on a larger diameter disc with the same
CONTACT patch. ie.

the Force being applied to the brakes using the same master clyn and
caliper are the same,

but the distance from the center of the disc is now longer. so now with a
little simplified

physics magic. Im sure the ME's here will expand on the physics.

so there..

and fade can occur for several basic reasons.

* the amount of force at the wheel decreases due to losses in the system
  -- ie. the master clynder hits the stops and has no more volume of fluid
to press.
     -- losses can be due to a leaky master clyn, leaky wheel clyn.
     -- the rubber hoses expanding enough to lower the volume of fluid
transferred to the
          wheel clyn there by reducing the force applied.

* the coefficient of friction decreases at the disc/lining interface.
  -- get better pads.
  -- cool the system.

* the coefficient of friction decreases at the road/tire interface.
   -- drive on better roads <VBG>
   -- get stickier tires... and no complainin' metzler
          ME-1 CompK's last 1500 - 5000 miles(not a miss print) and are
150 - 200 a Tire.
	  but hey you can leave a thumb print in em after riding around
the block.
	  they actually pick up loose dirt. Ive gone thru two sets in a
riding season before

________speculation below ________________

does improving the front brakes alone make a difference.
I suppose its time to try it out.
we'll have to have everybody with all the diff combinations all get the
same pads.
change em. and bed them in properly. verify that all brake systems work
properly.
and do panic brake tests on the runway measuring distance. with different
drivers swapping

cars.

but my prediction based on the number of times ive panic braked on
motorclcyes where i get to

actually modulate the rear brakes seperately from the front is that as
long as the rear

brakes are adjusted properly according to the bently the larger brakes in
the front will

decrease the stopping distanc.

make more passes


brian