Frine: Intrebari & Raspunsuri Options

[f1anatic]

INTREBARE: Am Bugatti Veyron dar in curbe, pe circuit sau pe strada, vecinul cu Ferrari Enzo FXX frineaza intr-o distanta mai mica. Ce pot face sa reduc distanta de frinare a masinii ?
RASPUNS: Multe. Depinde cit de mult timp, efort si bani doresti sa investesti si ce anume doresti sa obtii.

Nu toata lumea are nevoie de performante la frinare care sa rivalizeze o masina de Formula Unu. Pe de alta parte, cunosc persoane care au pus un "Big Brake Kit" pe a lor masina si se pling ca nu frineaza la fel de bine ca atunci cind masina era stock.

In primul rind, ca am mentionat Formula Unu, uite citeva date despre
2000 Jaguar R1 Formula One (Road & Track, October 2000)
Brakes: Front & Rear 10.9 inch vented discs with 6 piston lithium alloy calipers, carbon discs and pads
No Brake Assist
BHP > 800 @ 17,500
Weight ~ 600 kg including driver and engine/transmission fluids (not including racing fuel)
Acceleration:
0-60 mph (~100kph) @ 2.7 sec
0-120 mph (~200 kph) @ 4.8 sec
1/4 mile @ 181 mph @ 9.4 sec
Braking
From 60 mph (~100 kph) @ 72 ft (~22m)
From 80 mph (~130 kph) @ 118 ft (~36m)
0 mph to 100 mph to 0 mph @ ~ 6 sec

Nu cred ca vreunul dintre noi sa aiba o masina de F1 in garaj sau ceva cu performante relativ apropiate si nici Superlicenta de Pilot F1 nu avem (adica pregatire de curse profesionala)...dar cred ca toti sintem curiosi cam la ce distante de frinare sa ne asteptam. Distanta totala parcursa este mai mare insa - deoarece exista si un timp de reactie (in care percepi pericolul, si actionezi cu piciorul pe frina).

Un grafic de pe website-ul BBC


Iar daca ai timp si te plictisesti, atunci poti arunca o privire si poti descoperi capatul internetului vizitind situl
National Highway Traffic Safety Administration
http://www.nhtsa.dot.gov/
si folosind cu incredere functia de cautare.

Inarmati cu atitea grafice si detalii, sa ne indreptam in sfirsit atentia la FRINE.

Primul lucru care trebuie facut pentru a imbunatati frinarea masinii este sa schimbi cauciucurile
De ce ? Well cauciucurile sint cele care sint in contact cu asfaltul. Coeficientul de frecare intre cauciucuri si asfalt dicteaza cit de bine va frina masina.

1) Cauciucurile de curse/autocross/ de vara
La F1 se foloseau "slicks"; iar in mai toate seriile profesioniste, toate cauciucurile de uscat sint netede. Acum, cauciucurile tip "skicks=netede" acestea sint bune numai pe asfalt uscat si fierbinte, si sint moi si se tocesc repede si opereaza eficient numai la temperaturi ridicate. De ce credeti ca plotii de F1 cind sint in turul de incalzire sau in spatele la Safety Car trag de volan stinga-dreapta si frineaza puternic ? - Pentru a mentine temperatura ridicata (optima) in frine si cauciucuri. Cind aveti posibilitatea, comparati un cauciuc de vara cu unul all-season. Si cauciucurile de vara se apropie prin design de "racing slicks" chiar daca au canele: forma si directia canalelor este diferita si nu sint adinci sau late. La rindul lor, cauciucurile de vara...sint bune mai mult in conditii de uscat si cind e cald.

2) Cauciucurile "all season" sint mai dure, au canale pentru a disipa apa si preveni hidroplanarea si opereaza pe o plaja larga de temperaturi. In functie de stilul de condus, pot fi bune cca 25-30,000 de mile.

3) Cauciucurile de iarna au alta constructie, sint mai moi, au canale mai adinci si opereaza bine la temperaturi coborite. In mod normal tin 2-3 ierni, dar daca le folosesti cind temperatura asflatului este in medie peste 5-7 grade C atunci se vor toci foarte repede si nici nu "presteaza".

Cam la fel stau lucurile si cu "upgrade" la sistemul de frinare
Putem incerca o clasificare sumara in functie de modul de condus.

STREET
- condus moderat, nu agresiv, frinari lente, de la viteze mici
- placutele de frina au viata lunga, nu fac zgomot si praf
Ca upgrade cel mai bine este sa utilizeze placute de frina cu coeficient de frecare ceva mai ridicat (ca OEM) si cu o plaja a temperaturilor de operare cit mai larga (-20 pina la 250 C).

STREET TOURING
(imi plac numele astea in engleza) Stilul acesta de condus este pentru cei ce se cred zei ai strazii/autostrazii, caracterizat prin frine lungi si dese si bruste de la viteze ridicate.
Ca upgrade cel mai indicat sint
- placute de frina performante, care opereaza bine la temperaturi mai ridicate
- lichid de frina cu temperaturi de fierbere cit mai ridicate (DOT 4+)
- discuri de frina cu slot/gaurite (pentru disiparea caldurii)
- stainless steel brake lines (mai greu de explicat...dar tot ce pleaca de la master brake cylinder/servo frina si pina la etriere trebuie sa fie teava de metal. Orice este din cauciuc sufera de expansiune cind este aplicata presiune prin el)

COMPETITION
Numele spune totul nu ? Este nevoie de frine care sa opreasca masina de la viteze mari, des, si fara sa dea semne de oboseala. Tot ce este enumerat la STREET TOURING este valabil si aici, dar bineinteles putem vorbi de Big Brake Kits care in general contin
- discuri ma mari ca diametru (gaurite/slotted)
- discuri mai groase (pentru disiparea caldurii)
- etriere cu multe pistonase permitind o suprafata de apasare pe disc mai mare si mai uniforma
- placute de frina care opereaza bine numai la temperaturi inalte

Vreau sa imi schimb placutele de frina. Ce gasesc pe piata ? Cum sa le aleg ?

1) Durata de viata
2) Coeficient de frecare
3) Praf/Zgomot
4) Temperatura de operare

E greu de gasit ceva care sa combine cele 3 calitati. Placutele cu durata de viata lunga sint mai tari, frineaza mai prost, nu fac praf, au plaja temperaturilor de operare medie (si la frig, si la cald). In schimb ce frineaza bine dureaza putin, face praf, zgomot si nu tine decit la cald. Cum o dai nu o nimeresti.

Pentru mersul pe strada e clar ca trebuie ceva care sa "tina" si la frig...si la cald. O plaja a temperaturilor intre -20 C si 250 C este probabil optima.

Ce lichid de frina imi trebuie?
Simplu: lichidul de frina cu cel mai ridicat WET BOILING POINT ! Lichidul de frina absoarbe umezeala de aceea cind completezi lichidul de frina sau cind il inlocuiesti complet, trebuie sa folosesti o sticla noua. Umezeala si apa in lichidul de frina dau frinelor senzatia de "moale" (bineinteles si/sau aer pe traseu)
Exemplu: Motul RBF600 sau ATE Super Blue

Ce e aia stainless steel brake lines si chiar imi trebuie
Chiar mergi la curse ? Iti schimbi etrierele ? Mai mult ca sigur nu ai nevoie...
Exemplu: Cobb SS Brake Lines

Care-i vraja cu Big Brake Kits
Nu-i nici o vraja. Insa daca tot ce faci este sa mergi pe autostrada si prin oras, chgiar la viteze mari; NU ai nevoie de ele. Daca esti un serios pareticipant la curse si ai de gind sa ii respiri lui Schumi in ceafa ore intregi pe circuit, atunci ai nevoie de ele.
Exemplu: RalliTEK/AP Racing 6 Piston Big Brake Kit

Ceva in plus despre discurile de frina ?
Pai slotted vs. drilled. Slotted este un fel de "autoventilate" cu 2 suprafete unite intre ele de niste nervuri prin care poate sa intre aerul. "Drilled" sint gaurite. Acum, pot fi gaurite din turnare...sau gaurite ulterior. Sint scumpe, bune dar nu mereu fiabile.

Ok atita vorbaraie, saracia omului. f1anatic oare ce are pe masina ?
Eu sint sarac si cinstit. Nu am decit Cobb Street Formula Brake Pads si rotoarele erau bune - doar resurfaced. Cred ca mai merg un an. Si sint "slotted" (adica practic se autoventileaza) si dupa cum am mai mentionat sint destul de babane in diametru. DOT 4 Castrol brake fluid - cind imi voi face revizia tehnica la 30,000 atunci ii schimb eu si lichidul de frina, tot, complet cu ce am spus mai sus. Mai am juma de an pina atunci.

O alta treaba pe care am observat-o eu si o recomand este ca frinele cit si turbina (la masinile turbo) trebuie sa se raceasca in sarcina, nu imediat oprita masina dupa efort.

[f1anatic]

Un website excelent, sursa acestor informatii pe care le atasez mai jos. Daca sint nelamuriri sau se necesita o traducere din Engleza in Romaneste, va rog sa ma contactati.

http://www.raceshopper.com/

For general information on how disc brakes work - Read This:
http://www.brakeinfo.com
or
http://auto.howstuffworks.com/disc-brake.htm

Brake Pad Bedding-in:
For optimal use of any given brake system, the pads and rotor have to be compatible with each other. The bed-in procedure establishes that compatibility between the pad and rotor. This is achieved by a combination of rubbing speed, temperature, line pressure, and Inertia. Bed-in is also influenced by pad and rotor material chemistries. It is always recommended that only compatible pads and rotors be used in any given application.

Bedding in advantages:
1. Gradually heat treats the rotor and eliminates any thermal shock in the rotor.
2. Burn off volatiles and moisture from the resin that is near pad surface.
This will eliminate “green fade.”
3. Establish a layer of transfer film about a few microns thick on the rotor surface. Shearing of the film during friction is an effective source of friction force. Otherwise, when using a freshly ground rotor without the transfer film, the main friction force would come from cutting, plowing, or scoring the asperities on the rotor surface. This leads to inconsistent braking effectiveness.
4. Mate the two surfaces to a near perfect geometrical match, so that the contact area is high, and therefore the friction force is increased.
5. The performance of a fresh rotor/fresh pad system would be inconsistent. This is due to ever-changing structures and properties of the two mating materials. Bed-in of pads and rotor will form a stable transfer film.
6. If bedding in procedure is not applied, a stable transfer film may not be established for a long time. In other words, the rotor surface would have to be constantly regenerating a film that is not quite stable for a long time. This effect would reduce the performance and increase the wear.

Hawk Brake Pad Installation Procedure
Step 1:
Install Brake pads properly. Be sure pads are securely positioned in the caliper.
Step 2:
Flush system with fresh brake fluid.
Step 3:
Check all hydraulic parts for excess wear and tear.
Step 4:
Check disc for proper thickness, parallelism, and lateral run-out.
Step 5:
Check disc for scoring or grooves over .012" depth. If either applies, resurfacing or replacement is required.
Step 6:
If disc does not need resurfacing then contamination from the previous brake pads must be removed. Sand discs with Garnet sandpaper using moderate pressure. Use soap and water to clean off disc surface after sanding and machining. Discs should be free and clear of oil, grease, and brake fluid.
Step 7:
Inspect calipers for freedom of movement. Lubricate where necessary.

Hawk Brake Bedding-in Procedure
Step 1:
Make 6-10 slow-downs from approximately 30-35 mph to 5 mph. applying moderate pressure. Do not come to a complete stop.
Step 2:
Make an additional 2 to 3 harder stops from approximately 40-45 mph. to zero.
Step 3:
DO NOT DRAG THE BRAKES! (after stopping - do not leave your foot on the brake pedal)
Step 4:
Allow 15 mintues or more for the brake system to cool down.
Step 5:
Your new Hawk pads are ready for use.

Ferodo Brake Bedding-in Procedure
Rofren Brake Pad Bedding-in Procedure
(see website)

SP Performance Rotor Installation Guide
Download SP Performance rotor installation guide here (PDF)

NOTE: SP Performance Rotors are direct-replacement parts.
They are the same size as the FACTORY ORIGINAL parts.

If you are looking for rotors that are different diameters, thicknesses, bolt-patterns, etc. than the ORIGINAL part for the car....
We recommend that YOU determine what vehicle (year, make, model) has the rotor size that you are looking for.
Otherwise, you may want to take advantage of our Consulting Service.

Our Telephone Support/Technical Assistance Policy:
Let us be very clear about this -
If you're planning on calling us to ask questions like :

- How does your product compare to XYZ product that you don't sell?
Why is your product better than XYZ product?
We don't answer questions relating our products to those which we haven't used ourselves or don't sell. We have more technical information regarding the products we sell on our website than almost any other manufacturer or distributor. Please read it - then you'll know.
If not, we recommend calling the other company or vendor and asking them the same question.

How long (many miles) is this product going to last on my car?
The short answer is: If you don't drive the vehicle - they'll last forever.
Otherwise, brake component life expectancy is dependent upon:
How you drive, What you drive, and the Conditions under which you drive your
vehicle. Brakes are supposed to wear out!
All of the components we sell should last as long, if not longer, than any normal stock component - and perform better during their life expectancy. In many cases- our customers report anywhere from 150% to 300%+ greater
mileage than from stock components.

Our advice, and the answers to 99% of your questions are available for reading below:

How can I Improve my vehicles braking performance?
Brake performance will be positively impacted by improvements in the following areas:
#1) Better Tires
#2) Better Brake Pads
#3) Larger Diameter Rotors (more brake torque)
Assuming that you have good tires on your vehicle- the simplest, and most cost effective improvement comes from BETTER BRAKE PADS.

What brake pads are the best? (Our Number #1 Asked Question)
The answer here is subjective. Only you know what you want out of your braking system. Some want more performance- some want less dust, etc... Every manufacturer that we carry is a 'class of the field' performance brake pad manufacturer. If there was ONE pad or ONE compound that was better than any other- then we wouldn't have all of these different manufacturers - would we?
In general, we always recommend using a high-quality, semi-metallic pad.
Semi-metallic pads offer premium stopping power and fade resistance. Many of the semi-metallic or hybrid pad compositions also offer very low dust and are noise free.
Lastly, I can tell you this: BRAKING IS A TRADE-OFF
You cannot have better braking perormance with less dust and/or less rotor wear. If you want better stopping power- then that comes with the price of potentially more brake dust and more accelerated rotor wear. If you give up a degree of performance- then you can have less dust and less rotor wear.
You cannot have your cake and eat it too!
Well -actually - you can - but we don't sell them - the product you need can be found HERE.

Why don't you recommend Ceramic Brake Pads?
Let's start by saying that ceramic brake pads have a place in the automotive industry. They were designed to be a low-dust, noise-free brake pad. They came into popularity after the discontinued use of asbestos-based brake pads. At that time, semi-metallic pads exhibited problems with higher noise and dust levels.
That being said, I can tell you that Ceramic Brake Pads were NEVER designed to be a performance brake pad! Some companies have done a terrific job marketing their higher-priced, ceramic pads to the consumer as a performance pad. Ceramic brake pads typically have lower friction coefficients, and act as an insulator - raising rotor temperatures in cast-iron disc systems. When you have a vehicle that has persistent braking problems- the last thing you want to do is install components that have a LOWER friction coefficient and that RAISE effective operating temperatures! See our section on how this can cause ' Warped Rotors "
Premium-grade semi-metallic or hybrid pads are more effective for handling elevated temperatures and dissipating heat away from rotors. Most, if not all, semi-metallic pads have a degree of ceramic content ALREADY IN the brake pad.
Premium-grade, semi-metallic pads can offer LOW-DUST, NOISE-FREE Performance without sacrificing stopping power and increasing rotor temperatures!
Most organizations with fleet vehicles and other extreme-service applications already know what we're telling you: High-quality semi-metallic pads offer the best combination of stopping-power and extended-wear of any brake pad type on the marketplace today!

Should I use the same components as specified as OEM?
OEM means Original Equipment Manufacturer.
Translation: A component manufactured by a third-party company and selected for use in the original vehicle. An OEM manufacturer will typically manufacture their part based on specifications and designs supplied to them by the vehicle manufacturer.

Your vehicle manufacturer selects components used in your vehicle based on a variety of factors. These include PRICE, quality, deliverability, and many others.
In most cases, the manufacturer will not select the BEST product available.
If all of the items that went into your vehicle were the best - your car
would cost 5-10 times as much as you paid for it!
The manufacturers certainly make decisions, in most cases, to use an adequate product- that meets their demands for price and quality. They may not use the cheapest component- because it would result in too many warranty returns.
However, there are thousands of recalls every year for components which the manufacturer has deemed defective.
You can check them out for your vehicle here:http://www.alldata.com/recalls/
The vehicle manufacturers make mistakes too!
In the aftermarket, you can choose from a range of lesser-cost, lower-quality components OR higher price, higher-quality components.
You have the choice!
Just because it was specifed as OEM- it doesn't make it better!
All of the components we sell are EQUAL TO or BETTER THAN the OEM specification for the original component.
Remember, Firestone tires were OEM on Ford Explorer trucks .
Did that make them better? Think about it!

How hot do my rotors get when braking?
Excel calculator is available on the website.
Feel free to change the values, and see how this changes the outcome.

The table above calculates an "average" temperature rise for your rotors
under a single-stop event.
Peak rotor temperatures can be at least TWICE as high as what is calculated .
Higher rates of deceleration will increase the peak rotor temperature more -
since the braking system has less time to dissipate the heat generated.
Under multiple decelerations, the temperatures move progressively higher -
because the rotors do not have a chance to cool to ambient temperatures.

What causes brake pad failure?
There is no single answer to this question - there are simply too many variables.
However, in general, pad failure is caused by excessive heat. Brake pad compounds are designed to operate within a certain temperature range. When the pad is overheated to a temperature above what the material was designed to handle- it will wear at an excessive rate, crumble, decompose, and the like.
Tip: Our Temperature Indicating Paint Kit may be useful in determining the
correct brake pad compound(s) for your application:
http://www.raceshopper.com/temperature_paint.shtml

What causes brake pad glazing?
Brake pad glazing is caused when the brake pad friction material is overheated.
This results in crystallized friction material on the pad surface and the brake disc.
Typical symptoms of glazed brake pads include: Poor stopping performance, vibration or brake judder, and cracks or fissures in the brake pad material.
Pad glazing is typically caused by operating the brake pads at a temperature above the specified temperature range of the friction material or not properly following the 'Bedding-in' instructions for the brake pads. Always follow the manufacturers brake pad bedding-in instructions and use a brake pad that has a temperature range that is sufficient for its intended use.

What is better- Slotted or Drilled Rotors?
Again - this is a subjective question. As they say- liars can figure- and figures can lie. Proponents of both sides will espouse the benefits of each.
We prefer 'Slotted Rotors' Why?
A few different reasons:
1) Many companies who produce aftermarket performance rotors may not use the best 'blanks' to start with. They do this because it allows them to make the rotors at a lower cost and sell them to you for less than other competitors- or, this way, they can compete with the larger manufacturers. Now, if you have a somewhat sub-standard rotor- and then you 'cross-drill' it - What do you think you're doing? Well, you're compromising the integrity of the rotor by drilling completely through the surface- and then it heats up- and if it isn't a quality blank- made from quality steel and alloy- What do you think happens then? Well, more likely than not- it will crack.
Remember, we're not saying ALL 'Cross Drilled' rotors are bad.
2) Cross-Drilling (in most instances) removes more braking surface area than slotting does.
3) A brake rotor is designed to do one thing: Convert kinetic (moving) energy to thermal energy (heat). What handles more heat- A cast-iron kettle or a pizza pan with holes in it?
4) Can you think of any professional race teams who still use cross-drilled rotors?
Most importantly: "You get what you pay for!"
If you buy a $20 set of brake pads or a $30 rotor- and then you have to change them every 5,000 or 10,000 miles - Is that really a bargain?

Why all performance rotors are not created equally ...
Here's a few examples:



Here's an instance where the time was not taken to create a program specifically for the rotor in question.
The result is that the machine has drilled though one of the cooling veins and has compromised the structural integrity of the rotor. SP Performance creates application-specific programs for every rotor that it manufactures - This insures performance, safety, and reliability.


Here's another example of improper engineering.
Incorrect programming and layout has caused the drilling and slotting pattern to be non-symmetric.
To 'fill in the gap' additonal randomly-spaced holes had to be inserted to 'make the rotor look right.'
This can create a situation where the rotor in question would be out of balance.
SP Performance ensures the highest quality and performance by creating application-specific
computer programs for every rotor that it produces.
All SP Performance rotors are custom machined by highly-skilled, factory-trained technicians, and the rotors are computer balanced after manufacturing.
It takes a little bit longer and may cost a bit more, but- ask yourself......
What would you rather be riding around on?


Are Big Brake kits really better?
Big brake kits that are incorrectly designed can acutally perform worse than your stock brakes. Bigger pads and rotors primarily do one thing: They dissipate more heat than the stock brake setup. They do not necessarily stop you in shorter distances. Stopping distances are impacted by the coefficient of friction of the brake pad used and the clamping force applied by the caliper. Bigger brake pads do not apply more pressure- they only apply the same pressure over a bigger area. But- Don't take our word for it:
Here's a link to the test data for StopTech with their upgrade kit on an Audi S4:
http://www.stoptech.com/technical/balancedchart.htm
Note the next closest stopping disance in the chart is the OEM system!
Here's another link to another test using a Nissan 350Z:
http://www.zeckhausen.com/testing_brakes.htm#Summary
Note that the stock brake system on the 350Z (non track model) utilizes a 11 3/4" front rotor. For their test- they upgraded this to either a 13" or 14" rotor!
So- you can put a 13" or 14" rotor on the front of the car - and it still only stops about 7 feet shorter than the stock 12" rotor.....
We applaud StopTech- they seem like good people- and they are one of the few companies providing REAL information. They tell you exactly what we tell you earlier:
If heat dissipation is of primary concern- then a big brake kit will reduce the rotor and caliper temperatures. Otherwise, Premium Grade Brake Pads with higher temperature range capabilities and a higher coefficient of friction will provide the best improvement in braking performance.

Can I use racing brake pads on the street?
Simple answer: NO. Why?
We're not your parents- and we can't TELL you what you can and cannot do-However, If you use racing pads for street driving - a few things will happen:
1) YOU WON'T STOP. In fact, you will probably blow-through the first 2 or 3 stop-lights, stop-signs and the like everytime you first get in your car and drive it. FACT. Just like other brake pads- racing pads are engineered to operature at a CERTAIN TEMPERATURE RANGE. They will not stop you for a hill of beans BEFORE they get to that temperature range.
2) YOU WILL DESTROY YOUR ROTORS. Racing pads are a much harder compound than streetable pads. When these pads are cold- they produce an EXCESSIVE amount of wear on the rotors. In some circumstances- the pad material can be 'as-hard-as' - if not 'harder-than' the rotor material itself!
Take a look at a Formula1 race sometime- you will see the team throwing out $1,000.00 Carbon Fiber Rotors after every session - and the pads are still good!

What makes Brake Pads work?
If you got to this section- You are a die-hard braking fanatic! - Congratulations! Now onto the SCIENCE OF BRAKING!

The simple answer is friction. BUT- that's only part of the answer!
Brake pads work with a combination of TWO FRICTION TECHNOLOGIES:

1) ABRASIVE FRICTION
This involves the braking of molecular bonds between the pad material and the iron in the brake disc. Pads that function on this basis (typically organic pads) tend to have a high wear-rate and low resistance to high-temperature brake fade.

2) ADHERENT FRICTION
Adherent friction is developed when a transfer-film of the same compound of the pad material is deposited as a very thin 'film' on the surface of the rotor.
In this instance, the friction is caused by a breaking of molecular bonds between the two like friction materials amongst themselves (one on the pad and one on the surface of the rotor)

Most performance brake pad manufacturers now manufacture pads that function as a combination of these two technologies. These pads tend to have higher coefficients of friction over a wider range of temperatures.

All of the manufacturers that we carry - Hawk, Ferodo, and Performance Friction use a combination of abrasive and adherent friction technologies to stop you safely- Whether it's going to the corner store- or slowing from 220 MPH in a F1 or Indy Car!
You can benefit from the same technology that race drivers like Jeff Gordon, Michael Schumacher, or Michael Andretti use to stop their race cars !

What causes 'Warped Rotors'?
Typically warped rotors are caused not by a failure of the rotor itself.
Warped rotors (in most instances) are caused by the brake pads being operated at temperatures outside of their specified range. When the pads get too hot the pad material actually melts and 'fuses' itself to the rotor surface and creates a 'bump' on the surface of the rotor. In most cases this is not noticeable to the naked eye. This creates an annoying vibration when the brakes are applied. The only solution to this is turning (grinding) the rotors or installing new rotors.
We do not recommend turning rotors: It removes additional metal and reduces the the thermal capacity of the discs.
The best way to combat this condition is to use GOOD QUALITY street performance brake pads which have a higher operating temperature range.
Properly 'bedding-in' the pads and discs is a must.
Tip: Our Temperature Indicating Paint Kit may be useful in determining the
correct brake pad compound(s) for your application:
http://www.raceshopper.com/temperature_paint.shtml

When mounting new rotors- they should be installed on the vehicle and indexed with a dial indicator to minimize runout. New rotor runout is typically between .002" - .005" However, failure to mount the rotors ON THE VEHICLE and measure TOTAL runout can cause a vibration even with brand new rotors. You should check hub runout as well- since a very small amount of hub runout (even as small as .002") can create additional runout of as much as .006" - even with perfectly true rotors.
This is similiar to mounting and balancing tires. Often times a rim and tire combination that would require additional weight to correct balance can be rotated and then require less or no weight to balance.
This means you should test the rotor in a number of configurations and install it in the confirguration which results in the LEAST amount of total runout.

What makes my brakes squeak- and how do i fix it?
Ok, here's the answer: http://www.delphi.com/pdf/techpapers/1999-01-0142.PDF
It's 8 pages long- and will tell you exactly what causes brake noise.
Did you read it? No? Ok, We'll summarize it briefly: High-pitched brake squeal is caused by a high-frequency vibration between the pad and the rotor. Brake noise is not caused solely by the brake pad. The brake rotor diameter, and stiffness of the disc are also factors in the offending noise. Metallic-Carbon pads (as opposed to organic (asbestos) pads) typically produce more inherent noise than the older organic pads. Different brake pad manufacturers use different and varying amounts of substances in their pads: Iron, Copper, Zinc, Other Alloys, Lead, Carbon, Ceramic compounds, Kevlar, and numerous other fillers. This variation in pad composition, geometric design of the pad, and the stiffness (density) of the pad material itself can also contribute to the noise. Lastly, all of these factors can be affected by environmental factors such as temperature and humidity.
Now, how do I fix it?
#1: Make sure you have straight and true surfaces on your rotors and pads. Turn, or replace rotors as necessary- do the same with the pads.
#2: Inspect calipers, caliper sliders, and all other mounting sufaces and metal-to-metal contact areas. (This includes the rotor to hub mounting surface which commonly becomes contaminated by rust and other debris!) Lubricate all metal-to-metal contact areas with moly grease or lube. Inspect complete system and make sure that rotors and pads are lining up 'true' when brakes are being applied.
#3: Apply anti-squeal moly lube or similar to backing plate of the pads - or use an anti-squeal shim between the pad and the piston contact areas. This will change (dampen) the frequency of the vibration and will help reduce the noise.
#4: Chamfering of the leading and trailing edge of the pads will also help to reduce noise levels.
#5: Inspect related suspension components to make sure worn components are not placing undue stresses on the braking system, calipers, and pads.

Still not fixed? Ok! - You've got a tough one! We recommend going here to get your Doctorate in Friction Science: http://www.frictioncenter.com
I hope you remember your ThermoDynamics lessons from Physics class!

Do I really need these more expensive, premium-grade components on my car?
Consider this:
In most instances, car disc brakes and rotors will last anywhere from 30,000 to 60,000 miles or more before needing replacement. If we estimate on the conservative side- and say they only last 30,000 miles- and the typical cost of premium components (rotors and pads) may cost $300.00 That averages out to a cost of 1 CENT PER MILE.
Now, what does it cost to put gas in your car?
You pay probably $1.50 per gallon for gas- and get approx. 30 miles per gallon. Based on that, you are currently paying 5 cents per mile- just for gas!
That's over FIVE TIMES AS MUCH as you pay to maintain the braking system on your automobile!
How much is it worth to maintain your vehicle's proper braking operation, your safety, and have the benefit of improved braking performance over the lifespan of the components?

In fact- the true ADDITIONAL COST of premium components is probably less then 1/2 OF ONE CENT - since inferior replacement parts typically do not cost less then half of the price of the premium parts we sell.

The 'Lifetime Warranty' Myth:
Some manufacturers and repair shops offer brake parts with a 'Lifetime Warranty'. Why do you suppose this is?
Without question, every brake component will fail with eventual use.
It is a wear part.
Could it be that these companies have an incentive to have you keep coming back time and time again?
More disconcerting is this fact: Inferior parts will fail sooner than Premium grade parts. Installing inferior brake components will cause not only the part in question, but also OTHER PARTS TO FAIL SOONER.
You decide:
Is it worth it to buy an inferior part- and keep getting it over-and-over again replaced for free- BUT have to pay labor, and pay for other brake components that have failed as a result of the part in question- OR
Would it be easier to buy the best, Premium Grade Components and have them last?

Sursa:
http://www.raceshopper.com/tech.shtml#brake_performance[/b]