gts rotors
09-13-2012, 09:46 AM
#121
Addict
Rennlist Member
Rennlist Member
tv... i have disagreed with mark on several discussions, but he is correct here..
I cannot understand how you can ignore the tires....
tyres ARE the limit of braking.... all breaks will lock up tires.. to say that modern street cars are not near the limits is ludicrous.. Their brakes WILL absolutely have the power to lock up the tires.
tires have EVERYTHING to do with stopping. it is the tires that link the car and braking system to the road surface. The kinetic energy to heat transfer is limited to the grip of the tire. it is the grip of the tire that keeps the rotor turning against the friction of the pads. The friction of the tire/asphalt has to exceed the friction of the pad/rotor to keep the tire turning. if the friction of the pad rotor exceeds the friction of the tire/road the wheel stops and the tire slides, greatly increasing stopping distance.
to try and ignore the component of tire grip when discussing brakes, is like ignoring gravity when discussing parachuting....
rpetty2
quit embarrassing yourself, your father and Mark.......
when you are acting like an idiot, then using Breaks when talking about brakes, and continuing to use the wrong word after being corrected makes you sound like an idiot, and therefore treated like one...
your dad comes here,and i think he would be very embarrassed with your behavior here.
Also Mark Gets far too much unjustified grief here.. now him being friends with you will be used against him.... you are acting like a tool and people will give HIM grief for it....
if he is really a friend, you should straighten up as your behavior is affecting him here..
I cannot understand how you can ignore the tires....
tyres ARE the limit of braking.... all breaks will lock up tires.. to say that modern street cars are not near the limits is ludicrous.. Their brakes WILL absolutely have the power to lock up the tires.
tires have EVERYTHING to do with stopping. it is the tires that link the car and braking system to the road surface. The kinetic energy to heat transfer is limited to the grip of the tire. it is the grip of the tire that keeps the rotor turning against the friction of the pads. The friction of the tire/asphalt has to exceed the friction of the pad/rotor to keep the tire turning. if the friction of the pad rotor exceeds the friction of the tire/road the wheel stops and the tire slides, greatly increasing stopping distance.
to try and ignore the component of tire grip when discussing brakes, is like ignoring gravity when discussing parachuting....
rpetty2
quit embarrassing yourself, your father and Mark.......
when you are acting like an idiot, then using Breaks when talking about brakes, and continuing to use the wrong word after being corrected makes you sound like an idiot, and therefore treated like one...
your dad comes here,and i think he would be very embarrassed with your behavior here.
Also Mark Gets far too much unjustified grief here.. now him being friends with you will be used against him.... you are acting like a tool and people will give HIM grief for it....
if he is really a friend, you should straighten up as your behavior is affecting him here..
Max decelleration governed by tyres (and their contact with the road which thus includes suspension damping etc.)
Max useable repeatable brakng force (we aren't discussing the one off braking olympics here) governed by ability of the brake system to dissipate heat.
09-13-2012, 10:16 AM
#122
Drifting
If a car's brakes are big enough so that they are not the limiting factor in stopping but the tires are, then stopping distance cannot be improved by making the brakes larger or making them out of a different material because the brakes are not the limiting factor. If you slam on your brakes driving on black ice, you think you will stop faster if you upgrade to bigger brakes or ceramic brakes??
Dan
'91 928GT S/C
475hp/460lb.ftWe have made some progress here. Now everyone admits that the brakes are doing the work and tires are the ultimate limiting factor.
Wally I already stated pages back -- wider tires are better for cornering, less effective for stopping and going relatively. (look back at my first long post about the tire patch)
Black ice and flying thru the air ---- really --- I have already used the term red herring.
And finally, tires being the limiting factor and different brake material making no difference. Like some have said here "all brakes can lock-up tires so its the tires that are the limiting factor", right?
WRONG
The F40 with 335/35 ZR 17 tires stops in 122ft
The Chevy Z06 with 335 rear tires stops in 93 ft
If all brakes have all the power they need since they can lock-up the tires and since these tires are the same huge steamroller tires, why are they 30 FEET apart on stopping ability. (it doesn't matter that 1 has 13" cast iron and the other has 15.5" ceramics, because it's the tires, right?)
Some rules to learn;
1) Clamping force has nothing to do with stopping
2) Tires have not reached their limit yet
3)ability to lock-up has nothing to do with ability to convert kinetic energy to heat
Some of you will never get it, put F1 tires on a drum braked ****box and it still won't stop well, but it will corner. (note to Kibort - Tesla has 14" brakes in front and 14.4" in back)
09-13-2012, 10:42 AM
#123
Nordschleife Master
09-13-2012, 11:32 AM
#125
Race Car
And finally, tires being the limiting factor and different brake material making no difference. Like some have said here "all brakes can lock-up tires so its the tires that are the limiting factor", right?
WRONG
The F40 with 335/35 ZR 17 tires stops in 122ft
The Chevy Z06 with 335 rear tires stops in 93 ft
WRONG
The F40 with 335/35 ZR 17 tires stops in 122ft
The Chevy Z06 with 335 rear tires stops in 93 ft
Science class. If you want to make such an experiment, you must make all variables constant except the one you are testing. So you would have to take two identical F40's or Z06's, fit one with 13" cast iron brakes and the other with 15.5" ceramic brakes without changing ANYTHING ELSE. Then you could use such test results to try and prove your argument.
And now the real kicker: a stock F40 has 235/45-17 tires in the front, whereas a stock Z06 has 275/35-18 tires in the front. You are using rear tire size to compare stopping distance
Dan
'91 928GT S/C
475hp/460lb.ft
09-13-2012, 11:50 AM
#126
Drifting
Really digging in your heels on this aren't you? Fighting the laws of physics all the way.
2 passenger cars share the record of 60-0 in 93 ft the Z06 and the Scud!
The Scud's front tire --- Tire Size, Front: 235/35ZR19
Still Laughing?
You are NOT battling me you are going against proven science, i am just the messenger.
09-13-2012, 07:31 PM
#129
Rennlist Member
Really digging in your heels on this aren't you? Fighting the laws of physics all the way.
2 passenger cars share the record of 60-0 in 93 ft the Z06 and the Scud!
The Scud's front tire --- Tire Size, Front: 235/35ZR19
Still Laughing?
You are NOT battling me you are going against proven science, i am just the messenger.
2 passenger cars share the record of 60-0 in 93 ft the Z06 and the Scud!
The Scud's front tire --- Tire Size, Front: 235/35ZR19
Still Laughing?
You are NOT battling me you are going against proven science, i am just the messenger.
now below! oy boy! you use the wrong tire size for the ferrari. they dont use 335s up front! however i do and they stop much better than if i had 275s up front. entirely different arguement!
why do they stop 30 feet apart?? abs. setup, center of mass, etc etc. driver , conditions, etc etc!! its not the ceramic brake rotors, there could be a little issue with the F50 in the area of tire size. they have 235s up front ,while the x06 has the 335s up front. that is the difference.. its done ALL the time! there is no advantage of cf brakes, only in heat dissipation, after multiple braking activity, and certanly racing laps
note to YOU TV, clamping force, at any temp absolultey determines stopping distances. its what gives you the Acceleration (or deceleration) in A=F/M.
if you cant develope the force, you cant make the deceleration. the tire, again, is the conduit. its the transmission. all tires need a certain slip to be optimal. without it, too little or too much, you dont stop as quick. this is where ABS, a good one, will come in to play , OR, the driver with a skilled foot.
IF the brkae sytem can handle and generate the same clamping force,even though it might require more pedal pressure, and the tires are the same, the car will stop the same with a skilled foot. this is KNOWN logic and fact. try and prove this wrong. get your facts straight!!!!!
The other main point of above, and what is key, is that CAN YOU generate the same clamping force with two different brake systems, one with CF, one with cast iron. yes, BUT, its tempurature related. this is why im pushing you to look at what happens with differnent brake pads and rotors. the cast, at high temps will not be as effective, after a few stops. pads, same thing. too hot, they dont work. too cool, they dont work. in many cases cast works better , especially during a cold stop run. both can disappate the heat when starting at ambient. only one can disappate the heat after they start at 700 degree F. this is KEY KEY KEY@!!!!!!!!!!!!
We have made some progress here. Now everyone admits that the brakes are doing the work and tires are the ultimate limiting factor.
Wally I already stated pages back -- wider tires are better for cornering, less effective for stopping and going relatively. (look back at my first long post about the tire patch)
Black ice and flying thru the air ---- really --- I have already used the term red herring.
And finally, tires being the limiting factor and different brake material making no difference. Like some have said here "all brakes can lock-up tires so its the tires that are the limiting factor", right?
WRONG
The F40 with 335/35 ZR 17 tires stops in 122ft
The Chevy Z06 with 335 rear tires stops in 93 ft
If all brakes have all the power they need since they can lock-up the tires and since these tires are the same huge steamroller tires, why are they 30 FEET apart on stopping ability. (it doesn't matter that 1 has 13" cast iron and the other has 15.5" ceramics, because it's the tires, right?)
Some rules to learn;
1) Clamping force has nothing to do with stopping
2) Tires have not reached their limit yet
3)ability to lock-up has nothing to do with ability to convert kinetic energy to heat
Some of you will never get it, put F1 tires on a drum braked ****box and it still won't stop well, but it will corner. (note to Kibort - Tesla has 14" brakes in front and 14.4" in back)
Wally I already stated pages back -- wider tires are better for cornering, less effective for stopping and going relatively. (look back at my first long post about the tire patch)
Black ice and flying thru the air ---- really --- I have already used the term red herring.
And finally, tires being the limiting factor and different brake material making no difference. Like some have said here "all brakes can lock-up tires so its the tires that are the limiting factor", right?
WRONG
The F40 with 335/35 ZR 17 tires stops in 122ft
The Chevy Z06 with 335 rear tires stops in 93 ft
If all brakes have all the power they need since they can lock-up the tires and since these tires are the same huge steamroller tires, why are they 30 FEET apart on stopping ability. (it doesn't matter that 1 has 13" cast iron and the other has 15.5" ceramics, because it's the tires, right?)
Some rules to learn;
1) Clamping force has nothing to do with stopping
2) Tires have not reached their limit yet
3)ability to lock-up has nothing to do with ability to convert kinetic energy to heat
Some of you will never get it, put F1 tires on a drum braked ****box and it still won't stop well, but it will corner. (note to Kibort - Tesla has 14" brakes in front and 14.4" in back)
09-13-2012, 07:45 PM
#130
Rennlist Member
What is that? How can you compare just two data points on two completely different cars that were designed DECADES apart? What brand and tread tires are on both cars? What kind of ABS program is being used on both cars? What is the suspension setup on both cars? What is the weight distribution of both cars? On what kind of surface were these cars tested? What was the ambient temperature? What was the temperature of the surface?
Science class. If you want to make such an experiment, you must make all variables constant except the one you are testing. So you would have to take two identical F40's or Z06's, fit one with 13" cast iron brakes and the other with 15.5" ceramic brakes without changing ANYTHING ELSE. Then you could use such test results to try and prove your argument.
And now the real kicker: a stock F40 has 235/45-17 tires in the front, whereas a stock Z06 has 275/35-18 tires in the front. You are using rear tire size to compare stopping distance
Dan
'91 928GT S/C 475hp/460lb.ft
Science class. If you want to make such an experiment, you must make all variables constant except the one you are testing. So you would have to take two identical F40's or Z06's, fit one with 13" cast iron brakes and the other with 15.5" ceramic brakes without changing ANYTHING ELSE. Then you could use such test results to try and prove your argument.
And now the real kicker: a stock F40 has 235/45-17 tires in the front, whereas a stock Z06 has 275/35-18 tires in the front. You are using rear tire size to compare stopping distance
Dan
'91 928GT S/C
475hp/460lb.ftexactly. TVs facts are all over the map. i do remember the F50 and F40 brakes are 14" rotors. if the zo6 is 15" rotors, then fine. its not an advnatage for a 1 or two stop comparison. this is seen ALL the time in the cup car races. never do you see this kind of advantage for any of the cup cars with differnet brake rotors. some CF some cast. only in fade during a race , will the CF perform better. talk to a REAL brakes guy and ask these questions. race guy, not your kragen auto shop cashier.
09-13-2012, 08:08 PM
#131
Race Director
Okay comparing a 1990 tech F40 do a Z07 (carbon package remember) just isn't fair.....want to know why the Z07 out stops the LIGHTER F40.....TIRES....plain and simple......tire technology has advanced quite a bit since 1992...... Put identical tires on an F40 and try it again.....I do think the Z07 will win, but it say 93ft vs maybe 98.....
09-14-2012, 09:06 AM
#132
Drifting
The unenlightened side has said all along that all cars are over-braked, that it is tires, tires and tires. Yet you few have already conceded that the better tired mid-80's Formula cars with the softest grippiest tires didn't brake as well as todays less tired F1 cars.
The Scud has 235's upfront yet stops in the same 93 ft as the Z06 with 285's.
The tires stop cars crowd now wants to grasp at the ABS straw. If I walk into the Goodyear store today and ask for the ABS feature on their tires, how many will they have. Where is the ABS on the tire?
You post conflicting piece after conflicting piece clinging to the tire all the while forgetting that stopping is the conversion of energy, which the tire does not do, in fact ABS PREVENTS the tire from converting energy. Brake materials, Brake size, and to some extent ABS (part of the brakes system) have all improved. That is what stops cars. Put CRC brakes in place of CRSiC and gain another 20 feet. I could go on with more interesting info I have learned on this subject, but it is a wasteful enterprise.
The Scud has 235's upfront yet stops in the same 93 ft as the Z06 with 285's.
The tires stop cars crowd now wants to grasp at the ABS straw. If I walk into the Goodyear store today and ask for the ABS feature on their tires, how many will they have. Where is the ABS on the tire?
You post conflicting piece after conflicting piece clinging to the tire all the while forgetting that stopping is the conversion of energy, which the tire does not do, in fact ABS PREVENTS the tire from converting energy. Brake materials, Brake size, and to some extent ABS (part of the brakes system) have all improved. That is what stops cars. Put CRC brakes in place of CRSiC and gain another 20 feet. I could go on with more interesting info I have learned on this subject, but it is a wasteful enterprise.
09-14-2012, 08:57 PM
#133
Rennlist Member
tv.
you have used the term red herring several times... but all are incorrect usages...
"A red herring is a clue which is intentionally or unintentionally misleading or distracting from the actual issue.[1] The term is mostly used to claim that the argument of another person is not relevant to the issue being discussed"
we were using analogies.... they were not attempting to mislead ot distract, they were used as analogies to compare similarities in different scenerios.
black ice is a VERY good example as to why tires are the limiting factor of brakes... if tires make no difference as you have claimed, then you can stop a car on black ice as fast as you can on asphalt. if the friction of the tire on the road makes no difference then there would be no difference between the tow scenarios. After all, the ice would not have any effect on the rotor/pad function.
Mark did not say wider tires were better, he said better tires would stop you faster.
wider tires/skinnier tires are not what is important.. the friction of the contact patch is what matters...
you are being too narrow sighted focused on energy transfer.... come on, use some common sense....
first, the tires DO transfer heat.... take the tempp of a tire before and after a HARD braking from high speed.... it will raise in temp. so is is a heat sink to a small degree..
second, without the frction of the tire there would not be any energy transer.... if the tires have very little grip, the pads cannot exert much friction on the rotor therefore converting kinetic energy to thermal energy.. you will have no delta T...
the friction of the tire on the road surface is the link that allows any transfer. the stationary pad exerts friction on the rotating rotor.... what is the rotating rotor linked to... what is feeding the kinetic energy into the rotor..... DUH, oh my goodness it is the hub.... what is feeding the energy into the hub.... whell golly geee... the rim......
whell what is supplyint the energy to the rim..... holly Moses the tire......
when you apply the friction to the rotating rotor, why does it not stop instantly??? the rotating mass of the tire/wheel assembly? nope...
could it be the momentum of the car... bingo.... well lets think for a minute... what actually connects the momentum of the car (the kinetic energy) to the braking system... the friction of the tire to the road...
if there is no friction of the tire/road contact patch, you CANNOT stop the car.....
the more friction between the tire/road.. the more friction can be applied to the turning rotor by the stationary pad... the friction is the method of transferring the energy from kinetic to thermal.... why is this so difficult to comprehend?
the greater the friction between the tire/road, the more friction can be applied by the pad, therefore converting more energy...
you are totally correct in the energy conversion, but you are missing the most important link in that chain
the law of conservation of matter (energy) says that matter (energy) can neither be created nor destroid... it simply changes form....
what YOU are claiming is that you some how magically create and store energy in the rotor, and the rotor/ pad friction convert it to energy.....
it is the friction of the tire/road that allows the kinetic energy of the car to "travel" into the rotor
if you still think that tire friction is not the limiting factor, you are beyond reason, and like an ostrich with his head in the sand... the physics don't lie... i minored in physics....
without the rotors being driven by the tires there is no energy transferred into the rotors... the energy turning the tires is the energy of the car..
but i still love you.... even though you are wrong.....lol
you have used the term red herring several times... but all are incorrect usages...
"A red herring is a clue which is intentionally or unintentionally misleading or distracting from the actual issue.[1] The term is mostly used to claim that the argument of another person is not relevant to the issue being discussed"
we were using analogies.... they were not attempting to mislead ot distract, they were used as analogies to compare similarities in different scenerios.
black ice is a VERY good example as to why tires are the limiting factor of brakes... if tires make no difference as you have claimed, then you can stop a car on black ice as fast as you can on asphalt. if the friction of the tire on the road makes no difference then there would be no difference between the tow scenarios. After all, the ice would not have any effect on the rotor/pad function.
Mark did not say wider tires were better, he said better tires would stop you faster.
wider tires/skinnier tires are not what is important.. the friction of the contact patch is what matters...
you are being too narrow sighted focused on energy transfer.... come on, use some common sense....
first, the tires DO transfer heat.... take the tempp of a tire before and after a HARD braking from high speed.... it will raise in temp. so is is a heat sink to a small degree..
second, without the frction of the tire there would not be any energy transer.... if the tires have very little grip, the pads cannot exert much friction on the rotor therefore converting kinetic energy to thermal energy.. you will have no delta T...
the friction of the tire on the road surface is the link that allows any transfer. the stationary pad exerts friction on the rotating rotor.... what is the rotating rotor linked to... what is feeding the kinetic energy into the rotor..... DUH, oh my goodness it is the hub.... what is feeding the energy into the hub.... whell golly geee... the rim......
whell what is supplyint the energy to the rim..... holly Moses the tire......
when you apply the friction to the rotating rotor, why does it not stop instantly??? the rotating mass of the tire/wheel assembly? nope...
could it be the momentum of the car... bingo.... well lets think for a minute... what actually connects the momentum of the car (the kinetic energy) to the braking system... the friction of the tire to the road...
if there is no friction of the tire/road contact patch, you CANNOT stop the car.....
the more friction between the tire/road.. the more friction can be applied to the turning rotor by the stationary pad... the friction is the method of transferring the energy from kinetic to thermal.... why is this so difficult to comprehend?
the greater the friction between the tire/road, the more friction can be applied by the pad, therefore converting more energy...
you are totally correct in the energy conversion, but you are missing the most important link in that chain
the law of conservation of matter (energy) says that matter (energy) can neither be created nor destroid... it simply changes form....
what YOU are claiming is that you some how magically create and store energy in the rotor, and the rotor/ pad friction convert it to energy.....
it is the friction of the tire/road that allows the kinetic energy of the car to "travel" into the rotor
if you still think that tire friction is not the limiting factor, you are beyond reason, and like an ostrich with his head in the sand... the physics don't lie... i minored in physics....
without the rotors being driven by the tires there is no energy transferred into the rotors... the energy turning the tires is the energy of the car..
but i still love you.... even though you are wrong.....lol
09-14-2012, 11:51 PM
#135
Race Car
I see that you sir, have also stepped into the RED HERRING!
Is it also a red herring that with max performance tires, any given car's stopping distance is longer when the temperature outside is 40 deg F as opposed to when the temperature outside is 90 deg F? Surely if it is all in the size of the brakes, stopping distance should be the same?
Dan
'91 928GT S/C 475hp/460lb.ft
Is it also a red herring that with max performance tires, any given car's stopping distance is longer when the temperature outside is 40 deg F as opposed to when the temperature outside is 90 deg F? Surely if it is all in the size of the brakes, stopping distance should be the same?
Dan
'91 928GT S/C
475hp/460lb.ft