- dsm3383 wrote:
- First of all, larger rotors = larger contact force which leads to better braking. Tires do play a role but comparing with the same tires but brakes with larger rotors/pads you will experience a performance gain in your braking system.
Second, big brake kits don't just operate off of larger rotors. Yes, the stoptech cheap "big brake" kit does but it really is not a big brake kit.
A true big brake kit (Wilwood, Brembo, etc...) truly gets the stopping power from your caliper upgrade!!! We have a measly two piston caliper on our tC. Get a Brembo upgrade and you can choose between a 6 or 8 piston caliper. That is a huge substantial increase in hydraulic power to mash the pad against the rotor and distribute the force evenly through the pads. That is truly the largest factor when you examine big brake kits.
Third, cast holes/slots are weaker than machined. Rotors most important material property for operation is being HARD. When you machine metal you "cold work" the metal which increases stresses in it that change the grain structure at those HAZ (heat affected zones). The grain structure changes to being harder and more brittle (better compression strength). So, in reality machining after casting will create those areas (the slots/holes) where most people will assume as the weak spots actually the strongest parts on the rotors.
You also have to remember that you have to machine the rotor after being cast to produce the finished product. So, you automatically build these stresses in the rotors unless it undergoes a heat treatment process afterwards. Brembo only casts with the holes because its less material consumption thus cheaper manufacturing cost. They make it cheaper and sell it to you for more cause it is the "brand" name.
I dont see anything true about this post.
Again, I am no expert tho, but the rationality behind it all just doesnt seem to make sense or match anything I have ever hear or read. (Doesnt mean I am right tho)
Tires are the 100% limiting factor, UNLESS the stock setup has the in ability to take the wheels to lockup/ABS. And the tires are what determines that point.
If you have tires made out of SOLID frozen ice and you apply your brakes they will instantly go to lock up because traction will be lost. If you have tires made of CONTACT CEMENT it is going to take ALOT of pressure to bring them to lock up because they are going to grip everything and bring the car to a hault. Now apply that to a narrow range of a better tire over another tire and it all still applies, (just not so blown out of proportion)
yes like you said, a larger surface and caliper will give you more breaking force, but if the original force has the ability to stop the rotor from turning, how can there be more of an ability to stop the rotor from rotating? (short of makeing it spin backwards!!!!!!!!!)
The only gain is it takes less pressure to stop it from rotating due to the surface friction. Now that would be wonderful if the stock setup had human muscles and got tired. But our system driven on a road or even autocross, will NOT fade.
(none of this applies to a large circuit track, then you are right you will see MAJOR gains because brake fade and wear will become an issue.)
Oh and see my analogy of friction in my 2nd post.