The Truth about FOX FRONT BRAKES!

93 teal terror · Feb 18, 2004

Mustang5L5 said:
Ok lets try this....

F = pressure x area

F = 1000psi x 12 in^2 (rough estimate of max brake pressure and stock rotor surface area)

F = 1000 psi x 11in^2 (area of crossdrilled rotor)

Fsolid = 12000 lbs
Fdrilled = 11000 lbs

F is our normal force N

Now we use this equation Fk = Muk * N (Mu is a symbol that my computer can't generate but you engineering guys should know what i am talking about.

Fk is the frictional force
Muk is the coefficient of friction
N is the normal force from above

I have the Coeff of friction of leather on metal is 0.50. I have no idea what the actually MuK is so we will use that number since it's the closest i could find to brake pad on metal

.5 X 12000 = 6000 lbs-F (Frictional Force on solid face rotor)
.5 X 11000 = 5500 lbs-F (frictional force on drilled rotor)

I may not be 100% right on units, but that's what i have to prove that a larger contact area of a pad will give you more stopping force.

Does that check out with any of your other engineering/physics guys?

Your right except that theres more load on the drilled ones.......

The brake pad delivers whatever force the piston produces no matter what. With the drilled rotors you have less contact area with the rotor so lets say the Distributed load on the solid one is 50N/mm and the drilled one is 61N/mm
multiply that time surface area to get equivelant loading. So lets say the Suface area of the drilled is 984mm^2 and the SA. of the nondrilled rotor is 1200mm^2. When you multiply 50N/mm^2*1200mm^2 you get 60,000N. When you multiply 984mm^2*61mm^2 you still get 60,000N. Conservation of engery. When you calculate friction, you have to use the equivelant loading. So its the same Ffr no matter what. All less SA. is doing is increasing the pressure on the rotors. Does that make sense Mustang5L5?

93 teal terror · Feb 18, 2004

chaka said:
Well went to class and was thinking. So you have the force of friction turning into heat.
So now ForceFriction=MassRotor*(acceleration of Rotor). now assuming you decceleration is constant and it is is from V to 0. and without all the angular stuff.

Now the decceleration is related to the (acceleration of rotor) So the smaller the mass of the rotor the larger the (acceleration of rotor) must be which is directly related to the energy release. So they would heat up quicker, which has been proven since they are more likely to warp and crack (I know this is also in part with the holes) And why most roadracers try to route as much airflow over the brakes.

Does that make sense you physics buffs. I am a little rusty.

Yes they will heat up faster b/c of the increased pressure per mm^2 or in^2 whichever you like. All drilling holes in it is doing is increasing distributed loading.

Sicarius428 · Feb 18, 2004

It's all about drum breaks... They have the most surface area.
Kevin

Mustang5L5 · Feb 18, 2004

I think it's time we give this thread a break and move on.

I'm doing way too much thinking and not getting paid for any of it

horseplay91 · Feb 18, 2004

Mustang5L5 said:
How do these holes grab better? Explain this to us.

And answer this...if the holes allow you to grip better, why don't we drill our flywheels? Why did i go spend $$$ for a high performance clutch to increase grip when i would have just whipped out my trusty sears 18V cordless and went to town on my flywheel. I mean if your "holes in rotor increase grip" thoery is true, it should work on flywheels too right?

i know what your saying but that isnt really an apples to apples comparison. like mentioned earlier the friction caused by braking is dynamic. whereas in your example, would be static.

chaka · Feb 18, 2004

Mustang5L5 said:
I think it's time we give this thread a break and move on.

I'm doing way too much thinking and not getting paid for any of it

Same here. Time to think about all the projects that are piling up

chaka · Feb 18, 2004

DirtyD916 said:
actually chaka the smaller the rotor the smaller the acceleration. the velocity or acceleration of the rotor is all dependent on what point of the rotor your measureing. is it the outside edge of the rotor or is it the center? I mean its like a merry go round, the people on the outside section of the merry go round feel the greater acceleration and under go the greatest velocity because of there further distance from the center.

I didn't want to bother with the angular acceleration yet. Figured it would have just added more confusion. But this thread is done.

maverick0716 · Feb 18, 2004

Wow! This thread is hilarious! I also love how Custom89Stang ignores all the good points people are proving about the NON slotted/drilled rotors. And about the "holes" making the pad grab the disc better? Gimme a friggin break! Thats some major bull crap your spewing out there

One more point - If slottled/drilled rotors are so much better than why don't all the high performance cars have them? Have you ever seen the discs on an Audi S8? 14 inches, NON slottled/drilled.

miamifiveoh · Feb 18, 2004

maverick0716 said:
One more point - If slottled/drilled rotors are so much better than why don't all the high performance cars have them? Have you ever seen the discs on an Audi S8? 14 inches, NON slottled/drilled.

You can't use that argument around here Maverick, because it will be countered with, "Drilled/slotted is obviously better because Porsche uses them..."

maverick0716 · Feb 18, 2004

miamifiveoh said:
You can't use that argument around here Maverick, because it will be countered with, "Drilled/slotted is obviously better because Porsche uses them..."

I'm aware of that. And I do agree that they stop better/faster after normal non slotted drilled would start to fade (as in race applications) But if you take the same size rotors, non slotted vs. slotted/drilled and do a braking test from say 60 or 100-0 mph you would find the non-slotted will actually brake in less distance.

IndyBlk5.0 · Feb 18, 2004

Ok guys, this can be dragged out forever becuase of two simple facts. 1) people have their own independant opinions. 2) some people disagree with others just to disagree. I am taking no sides on this issue. It is simply user preferance, if you think they will be better than stock, then do it, if your conscience tells you no, then dont do it. Plain and simple, and quite frankly that is more than likely how it is going to end up happening anyways.

custom89stang · Feb 19, 2004

Mustang5L5 said:
How do these holes grab better? Explain this to us.

And answer this...if the holes allow you to grip better, why don't we drill our flywheels? Why did i go spend $$$ for a high performance clutch to increase grip when i would have just whipped out my trusty sears 18V cordless and went to town on my flywheel. I mean if your "holes in rotor increase grip" thoery is true, it should work on flywheels too right?

You've said this about 5 times already so why don't you explain it to us why holes in rotor increase it's stopping ability. Feel free to use as little actual fact as possible.

cuz ur a dumb'Kiss Me''Kiss Me''Kiss Me''Kiss Me' is why u spent it. i dont know enough about the mechanics/physics of a flywheel to tell u

custom89stang · Feb 19, 2004

Wow You Guys. Love The Controversy. I Am Reading Some Of The Points. Glad You Guys Think You Know Everything. I Actually Think Its Hilarious, But Alas I Think Everyone Is Right. Screw This Thread.

91BlckGT · Feb 19, 2004

custom89stang said:
Wow You Guys. Love The Controversy. I Am Reading Some Of The Points. Glad You Guys Think You Know Everything. I Actually Think Its Hilarious, But Alas I Think Everyone Is Right. Screw This Thread.

And screw you too. I've only managed to make it three pages in, but you've come across as arrogant and a know-it-all. I believe the title of this thread should be: "My opinion about FOX brakes".

I'll this thread for now, just to give me a chance to catch up on the reading. If I actually find some valuable tech in here, I'll leave it up, but thus far, I've only seen a combative stance from most...

**EDIT**

Well, I'm leaving it locked. I liked all this friction / stopping force talk, but it all comes down this:

Stock fox brakes do indeed suck. Upgrade them.

Slotted or cross-drilled do not provide any performance benefit whatsoever on the street. All they do is generate more brake dust.

Why do people add slotted or cross-drilled? Because they look sweet. At least that's why I put them on.

The Truth about FOX FRONT BRAKES!

93 teal terror

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That is…until I whipped out my Bissell

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