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# BRAKE DISC INFO
#
# Heat capacity
# Heat capacity is the amount of energy that can be absorbed by the disc before the temperature gets high enough to cause brake fade. The mass of the disc is proportional to the heat capacity. Therefore, a lighter disc will not allow as much energy to be absorbed as a heavy disc.
Solid vs Vented
# Vented discs are hollow with internal vanes. This increases the surface area of the disc and allows air to cool the disc mass more effectively. A 5Kg vented disc will cool much quicker than a 5Kg solid disc. In many cases, a vented disc can weigh less than a solid disc and still provide more effective braking because of the cooling effects alone.
Curved vs straight vanes
# The vanes inside vented discs provide structural integrity to the disc itself as well as cooling. There are several different styles of vanes:
# Straight vanes are the most common because they are easy to manufacture.
# Curved vanes are common in higher performance cars as they promote better cooling better than straight vanes.
Where does the air go?
# For solid discs, all the air travels over the surface of the disc - the same surface as the brake pads.
# For vented discs, a considerable amount of air flows through the interior. Because it's spinning so fast, it creates a vacuum and air is sucked into the center of the disc and forced out through the edges. The air follows the pattern of the internal vanes.
Drilled discs
# A common misconception is that the purpose of drilled discs is to promote cooling. This couldn't be further from the truth, The real purpose is to reduce weight.
# Drilling can allow brake dust and gases to escape, but with modern brake pads, this usually isn't a problem. Choosing a drilled disc for that purpose doesn't make a whole lot of sense.
# Many high performance cars like Porsche and Mercedes AMG come with drilled discs from the factory. For these cars, the drilling is mainly about the looks, just like bright red calipers. When people do serious high-performance driving on a trackdays, they usually swap to regular plain discs.
# Drilled discs generally wear out brake pads faster and produce much more brake dust as a result.
# Drilled discs have a shorter service-life than plain discs and tend to develop stress fissures/cracks over their lifetime
Grooved Discs
# Grooved discs keep the pad surface clean and allow certain gasses to escape which improves performance. not too many grooves though, you only need 6 or so, anymore and it it just for looks(e.g tarox cheese graters)
# For street driving they may make a marginal improvement in initial brake "bite"
# Grooved Discs are great for shedding water and mud off the rotor surface as in Rally racing or wet-weather racing.
# Grooved Discs do accelerate pad wear and produce more dust just like drilled discs do. They also add noise and vibration into the system. For many these issues are annoying enough to not choose grooved discs, unless you do alot of rallying!
Two-piece discs
# Two piece discs have several advantages including lower weight while maintaining most of the heat capacity and better cooling by having a more open center section
# Two piece discs increase costs and generally a poor choice for street cars. For racing, they are great!
Plain discs
# Plain discs are the best choice for 99.9% of applications
Name brand vs non-name discs
# Why pay double the money for a Brembo discs vs. GSF cheapo's? You guessed it there is pretty much no benefit. Its all the same stuff, Spend you money on brake pads
Specialist Discs (carbon, carbon-ceramic, carbon-kevlar, etc.)
# Some really expensive cars come with an option for fancy brake materials. These brakes are excellent for trackdays since they are relatively lightweight but can withstand extreme temperatures without brake fade. This provides a competitive advantage for racing.
# For the street, it doesn't help much at all, and they squeal alot and wear fast.
Warped discs
# if your discs are warped its because you have heated them up too much during hard breaking. probably nackered but you might be able to get them skimmed.
Reference
