Brakes: Fact vs Friction...

Hello,

I am interested in reducing stopping distance and weather/heat related issues, so I need to upgrade my brakes. This is for street driving.

I've narrowed the choices to Brembo X-Drilled or Brembo Slotted brakes. I heard rumors that the drilled tend to crack, while the slotted tend to increase wear-and-tear on the pads. Is this true?

Also, what are your experiences and recommendations with either Drilled or Slotted rotors?

Which is better for a daily driver?

Thanks!

:-)

Well first of all some details would be nice

What sort of car is it, what mods, (wheel sizes etc), and why do you think you need to upgrade the stock system?

I am interested in reducing stopping distance and weather/heat related issues, so I need to upgrade my brakes.
That's why.

And I didn't know that a given type of car needed slotted or cross-drilled rotors...

I don't know anything about the cracking of cross-drilled discs, but slotted rotors do wear out brake pads faster than X-ded since the slotted ones have more surface area.

just get bigger brakes. They dont have to be cross drilled or slotted, unless you're doing a lot of hard high speed braking. Unless you're driving an F1 car, they're just for looks and whatnot. Cross drilling and slotting is for cooling purposes, i.e. the cooler the brakes the better they work. But you're brakes shoulnt be glowing yellow with day to day driving. anyway, yeah bigger rotors should do teh trick, but dont overdo it, because if you're brakes are so powerful that you skid everytime, then you just defeated the purpose of getting better brakes :)

Keep in mind larger calipers and better pads make a MUCH bigger difference in overall praking performance than just different and/or larger rotors, and you may need to look into different master cylinders and possibly brake proportioning valves to optimize the system. Also, there's no such thing as too big a brake, the pedal is for modulating their power so you won't be locking up the wheels every time you stop.

You need to upgrade your brakes for "street driving" purposes? You must live near me, then. Yesterday, I hosed off my wheels, and about 10 pounds of brake metal washed on down the driveway. I swear, these roads are murder. It's not like I drive THAT fast. :smoker2:

For street and maybe light track usage, EBC makes a combo that's tough to beat for the money. OEM-size replacement rotors with curvy slotting and blind holes are as much as you'll ever need on the street, and they make two particularly good brake pads: Greenstuff and Redstuff. The green pads are terrific around town, and will only dirty your wheels if you punish them. I think they're mostly kevlar, and they withstand pretty extreme temperatures. On a light car, you might even get away with using them to halt you after a 1/4 mile run (but I wouldn't advise it). For a 2500+ lbs. car or any racing, you have the Redstuff pads.

This is an easy way to boost your stopping power, and make the car more enjoyable to drive. After a short break-in, these pads give terrific peddle feel, and brake fade is a thing of the past. Before going to a Wilwood kit or something else you don't need, check these out. The "Sport rotors" retail for about $80 I think, and the Greenstuff pads are around $50 (depends on your car).

because if you're brakes are so powerful that you skid everytime
Many cars come with ABS.

And yes, the only thing that matters in the end is the frictional contact between the pad and rotor.

whats brake fade?

isnt it possible to get allround brakes, one with lots of space to push the peddle down, where if you put it down just afew cms you can slow down smoothly from 20kmh and if your going 100mph you can slow down heaps fast from there by pushing the brakes down more.


i havent had much experiance with braking in cars,
like locking the brakes at mid range speeds (80-90mph) or braking at high speeds, but in my car the brakes overheat badly when i go on the expressway for 30 minutes, it seems hard to lock the brakes at any speed over 40kmh once they have heated up

when i "borrowed" my dads merc c200 i noticed the brakes just wanted to stop the car completly at 50kmh, it didnt have much room between slowing down slowly from 50 to stopping on a dime, why cant they make nice strong brakes that can also brake smoothly with ease at low speeds.

Brake fade is when the brakes become less effective as they get hotter. Brake components (pads mainly, I believe) will start to break down at high temperatures, and the materials that used to provide friction may degrade into lubricants. This is bad. OEM pads will be useless by 300 degrees (fahrenheit). The other, probably more significant, reason is hot gasses on the surface of the rotors, causing the brakes to float. Slotted rotors diffuse the gas more quickly, which is a major benefit.

The smooth braking action you're talking about is usually described as "linear" or "progressive" braking, and is a very desirable trait. Auto makers are putting more effort into achieving this than they used to. Go test drive a Porsche 911. Ferdinand's boys got it right some time ago. They use ceramic rotors, and they work. They're also extremely light. A very good reason to test drive before you buy.

Linear and progressive mean the opposite things...

Linear and progressive mean the opposite things

In the case of springs, yes (or sort-of, anyway).

In this case, I think that the issue is that you have a system that requires non-linear ("progressive") behaviour to achieve a linear-feeling response. So it can be simultaneously "progressive" and "linear."

Okay, that was sort of a confusing statement. Let me clarify.

I believe that when people use the terms "progressive" and "linear" in reference to braking, they're talking about the same thing. I generally use the term linear, but linear refers to both the effort of the driver and stopping power. The actual force exerted through the brake system and increases in friction as a result are progressive. Properly engineered brake boosters produce this braking curve which translates the effort being put on the pedal into a specifically proportionate amount of friction.

I could be totally wrong about this. It just seems to me that people have been using the terms interchangeably.