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      10-21-2007, 08:04 PM   #114
GregW / Oregon

Drives: 2015 M4 Coupe, 2012 ML350
Join Date: Nov 2005
Location: Lake Oswego, OR

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Originally Posted by devo View Post
+1 to the aforementioned post. More force over more of a swept area, making multi-piston brakes more effective than single piston ones. Everything else being equal, of course.

So, whether the rigid four and six piston "red" brakes on a Porsche offer "more" clamping force is moot. It is that they offer more clamping force over a broader area. Which is why BMW's brakes -in their current configuation- will not compete with Posche's over repeated hot stops. No matter how much road test data someone finds where the M3 bests the 911 in a single contest.

Whether or not better brakes are needed for the street has yet to be determined, however.

Great info, by the way!
I don't read that the way you do. The first most important "area" is the total piston area--A large single piston may have more area than dual pistons. This inceases potential clamping force and therfore stopping power.

"Increasing the size of the pads will not increase clamping force." The area over which the clamping force is applied is moot in terms of stopping power; larger "swept area" will only increas pad life, as each sq. cm. of pad is doing less work.

The second most improtant area is the rotor size; larger rotors offer a greater heat sink and area with which to dissapate heat, and greater moment arm for reverse torque application.

Greg Lake Oswego, Oregon, USA
2015 M4 Coupe - Silverstone/Sakhir/CF
2012 ML350

Last edited by GregW / Oregon; 10-21-2007 at 11:45 PM.