EBC BRAKES - REAR ROTORS (sold in pairs)

Brand: EBC

Product Code: GD7319

Availability:In stock

$ 336.56 0.00

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How to bed in new rotors

How to bed in new rotors on your car after a brake service or when going racing. The important thing to remember is that when replacing rotors you need to bed them in even more gently than pads. It is a regular misconception that a new rotor can be installed on a car and there is no need to bed them in.
The conclusion for those of you who don’t want the explanation is that to bed in new rotors you drive them gently for the first 1000 miles.

To bed in new rotors you need to first understand that all rotors are made from cast iron which is a natural material, very common in fact and it contains certain elements that can change or combine in their particle structure during both their formation into a cast object and in early use as a brake component which dramatically affect the performance, stability and strength of the iron material.

A Typical cast iron material used in aftermarket brake discs or rotors is grade GG25 or GG20 and almost all discs from Asia will use these grades and contain these elements. 

Carbon
Silicon
Manganese
Phosphorus
Sulphur
Nickel
Moly
Chromium
Copper
2.2
1.00
0.65
0.07
0.07
0.05
0.02
0.15
0.20

EBC new High Carbon GG15HC material is an even higher specification and contains these elements

Carbon
Silicon
Manganese
Phosphorus
Sulphur
Nickel
Moly
Chromium
Copper
3.72
1.74
0.05
0.05
0.108
0.40
0.45
0.16
0.80

More Carbon and Silicon in the GG15HC produces a more thermally stable disc that is quieter, resists cracks , dampens vibrations better and handles heat better.

Assuming that a brake disc has been made properly, with a good pearlitic structure to begin with, the onus then rests on the user to not create the conditions of heating and rapid cooling that will cause structural changes and therefore cracks to be formed in the braking surfaces.

In other words getting a rotor very hot and cooling it very quickly is not good news especially in its early life.

The best way to bed in new rotors is to use them gently over the first few hundred miles, not getting them too hot and letting them cool gently, for certain avoiding hard braking if at all possible (safety considered).

If you can do this by moderate street driving for up to 1000 miles you will condition your iron disc or rotors and that is the best way to bed in new rotors.

 

HOW HOT CAN A BRAKE ROTOR BECOME AND WHAT HAPPEN WHEN IT OVERHEATS ???

Once a disc goes above 727°C the pearlite in the matrix will start to decompose (degenerate) into ferrite. This change cannot be reversed, so once its starts to happen that is it. Ferrite is very weak so lots of ferrite can cause the strength of a disc to drop. The change from pearlite to ferrite can also cause the formation of craze cracks on the friction surface of the disc. Small cracks can then emerge to form larger cracks and in extreme cases the disc itself may crack completely. 

Heating above 700°C and stopping quickly i.e. parking, can also help induce stress into a disc – some thing you do not want – this can cause distortion and judder.

One point to consider before making your choice of sport rotor is the air noise that can be noticed with sport rotors. With all slotted rotors there will be an increase in air noise as the rotor passes beneath the pads under normal driving and braking. Some people like this kind of “Turbo” sound and others do not.

For this reason EBC produce two ranges of sport rotors, the 3GD or GD series being discussed here are the noisier of the two designs, our sister range the USR sport rotor range is MUCH quieter yet offers similar performance values.

Make your choice before you buy please.

Experience has shown us that on Truck and SUV the GD or 3GD series wind noise is almost unnoticed and on faster and tuned sedans and hot hatches the GD or 3GD series as we call them (they are both exactly the same item) is the preferred choice.

If silent braking with performance on a prestige or quiet car is your target buy then opt for the USR series, shown by clicking this link USR series.

 

CORRECTING ROTOR DISTORTION, ROTOR MISALIGNMENT AND CURE BRAKE VIBRATION

There are two main reasons for brake vibration. The first is steering geometry issues and the second is installation or hub run-out issues.

GEOMETRY ISSUES – One in seven cars suffers geometry problems during its life that can affect steering and cause brake vibration. These are NOT a product quality issue!!!!!!.These can happen by simply nudging a kerb or by driving over a pothole. EBC is not alone in recognising this problem but is the only brake supplier on the planet prepared to offer diagnosis and a SOLUTION.

INSTALLATION OR HUB RUN-OUT ISSUES – These cause what is known as DTV. The videos below show how to correct for brake vibration caused by DTV (Disc thickness variation). DTV develops in a car after 3000-4000 miles caused by runout built in to the car or due to incorrect alignment of the rotors at install. This is quite a common fault on modern cars and many cars require this at every rotor change. Drivers also confuse hub distortion with a rotor quality issue but in 99% of cases the DTV is a car problem, not a rotor quality problem. You can replace the rotors as many times as you like trying to solve vibration and the problem will only go away for a few thousand miles and then return. This means you have purchased new rotors in good faith but the problem IS NOT SOLVED AND WILL NOT GO AWAY PERMANENTLY until you perform this procedure. After this skimming of the rotor surface you will have smooth brakes , more effective brakes and ZERO vibration. It is even a very worthwhile practice when fitting new rotors to have all four rotors skimmed into perfect alignment on your car with this inexpensive procedure.   Rotor distortion due to DTV is very common, in fact ONE IN SEVEN CARS has a steering geometry problem either when it is built NEW or after nudging a kerb or hitting a large pothole (very common after road surface damage after winter snowy periods). Uneducated people still say “My rotors are warped”. Well the engineering facts are ROTORS DO NOT WARP, they are made of cast iron, they are very tough and can be run to red heat and cooled time after time and they will not distort, we do this day in day out on our dynos in the EBC lab. That's why the whole world still uses cast iron as a vehicle brake rotor material, there has never been anything to beat it and probably never will be. Pro Cut machines WORK ON BOTH PLAIN ROTORS AND EVEN BETTER ON SLOTTED AND DRILLED ROTORS OF ALL TYPES.