Like my subject line asks, are drilled and/or slotted brake rotors worth
the money or are they just another aftermarket gimmick to get my hard earned
money? Are any brands more reputable, etc.
PS, I decided to go back with a stock muffler system to kill the droaning
sound from the aftermarket setup that was on the car when it was purchased.
Unless you are tracking the car, drilled rotors are not worth it. In fact,
just replacing the stock rotors with drilled can actually lengthen stopping
distances, since the swept area is reduced! There was an article in
Car & Driver about a year ago that was interesting - you can probably
find it online...
oem parts like zimmerman rotors are very good,
there are also slotted ate powerdisks that poeple like, more $$
But as it was said, if you don't track the car, oem parts (zimmerman) is the
way to go... pads though, you may want to find a less dusty pad than the oem
You'll need to define what "better performance" means to you in order to
fully answer your question. Slotted or drilled have only a few
advantages over standard solid discs.
The holes or slots allow gasses which are put out by the pads from the
high heat of heavy braking to escape. So under this very limited
situation (this is the track thing everyone's been talking about) it may
improve braking. They also will help void brake dust or water should
either of these get onto the swept surface of the rotor. And of course,
they look *really* cool (like you are a racer even if you're not).
You actually *reduce* the contact area between each pad and the disk
surface therefore reducing the normal-condition braking performance.
They can act as a cheese grater on your pads causing them to wear out
significantly faster. They can cause your brakes to be somewhat noisier
(grinding sort of noise). Drilled holes can cause uneven heating and
cooling of the disk resulting in premature warping and the development
If you drive the car on the street, the only way to really get improved
brake performance is to get more or increased friction contact area with
the disk, which means either a different brake pad compound, or bigger
brake rotors and calipers (big brake kit), which will undoubtedly also
require larger diameter wheels to clear them. We're talking many, many
hard earned samoleans here...
To my way of thinking, the BMW brakes are already some of the best
performing available, and one of the many reasons that I buy my BMWs in
the first place. I'd try a few different types of brake pads and see
what you can find that you like. They are much cheaper and will have
more benefits and fewer liabilities that drilled or slotted rotors. I
don't know about you, but I've got (many) more important things to spend
my money on than a big-brake upgrade for a street driven BMW.
Now OTOH, if you *are* planning to race or autocross the car (and money
should be no object) by all means upgrade to Big Brakes with slots
and/or cross drilling. As the old adage goes; the fastest car around
the track is usually the one that can stop the quickest.
Rather than slotted/drilled rotors consider the diamond/slotted
rotors!They are better in my opinion over slotted/drilled rotors and
substantially longer pad life due to better heat
dissipation from the diamond shaped (holes)!
In a recent Shelby Mustang GT (that's 475 hp, by the way) pre-test Ford was
asked why they were not using drilled rotors. Answer was that drilled rotors
have a tendency to crack in heavy use and are not worth the trouble.
So what is the model and year of your auto? If performance increase is
what you are after then rotors alone are not the answer.
BMW is a parts-bin company. In other words you can mount parts from the
larger cars onto your car. For instance I have a 635csi and I can bolt
on 750i calipers, rotors, and master cylinder. I had to buy larger
wheels but the the performance was awesome. Another thing I did to
improve pedal feedback was to replace the old rubber brake hoses with
Stainless braided hoses. What this does is reduce the amount of
expansion (balloning), thus making the pedal feel less spongy.
Slotted and drilled rotors will eat brake pads and create lots of dust.
These rotors should be used with the pads the rotor manufacturer
recommend or poor performance will result.
No. All current BMW brakes would lock the wheels if the ABS didn't prevent
them. If your car doesn't have ventilated disks (air gap in the middle)
then it may be worth fitting those if you intend to rally the car or do long
alpine descents. Otherwise I would not bother.
The only road application that I am aware of them being useful for is
motorbikes, where the disks are outboard, get wet and the slots clear away
water allowing some braking effort on the first revolution.
Aircraft sometimes have them (in stacks), but the issue here is the huge
amount of energy to be dispersed in bringing tens of tons of aircraft to a
halt from 240kmph+ on very few wheels.
If you are experiencing fade in your BMW then you have a problem, probably
damp brake fluid.
The scams have it.
Unless you are racing, the slotted rotors are not very good for your car.
The same mentality that put the muffler system on your car is the one that
drives a person to slotted discs. You don't like the muffler, odds are you
won't like slotted discs either. The difference being, somebody else put the
muffler on ...
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