Quote:
Originally Posted by axeman71
Wow, big discussion for one evening. I don't understand the sarcasm in the first 3 or 4 posts, I was asking a serious question. Just saying "duh, bigger brakes are better" doesn't tell me why which is what I was asking. The misspelling was just me not paying attention (I am a bad speller though). I maybe didn't ask the question in a clear enough way.
Taking our Z's as an example: I expect the larger sport brakes to stop the car from 60mph to 0mph in a shorter distance than the standard brakes (btw, I have not yet read any reviews testing the standard brakes, they all test sport packages). I know from experience that the standard brakes produce enough friction on the rotor to completely stop the tire from rotating making the tire skid over the pavement (or, well the ABS come on but you know what I mean). So, why do the larger sport brakes stop the car in a shorter distance? Yes, the sport brakes have a larger surface area in contact with the rotor and produce more friction but there is already enough friction with the standard brakes to lock up the wheels. The only answer I can gather (both from this discussion and my own imagination) is the larger brakes allow greater control over the stopping force allowing the driver to push the brakes closer to the point of locking up the wheel without crossing over the point where the tire starts to skid.
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I think heat is like 90% of the reason for the move to bigger brakes in
most applications. Some people will find examples where that is not true, but the added absorption and dissipation area provides a huge benefit.
I don't think that a comparison in stopping distance between base and sport would do much good, as they sport different size/weight rims, as well as different stock tires in notably different sizes. I believe that the stopping distance would likely be very close.
I know I kept stock size brakes on my s2000, and despite the (relatively ) large rims I had on the thing, the stopping distance was in line with other s2k's sporting BBK's. On a track or in the twisties though, my rotors would heat up to the point where they were glowing red, while the rotors on said BBK's were still much cooler.
Contrary to the belief many will have, for the contact between brake pads and the rotor, surface area is irrelevant. The reason that surface area plays a role in other situations (notably tires) is due to adhesion (pieces of the tire bond to the road).