Originally Posted by N54_Fan
Hey Harold I just got the PFC 08 in today. I cant wait to try them out.
Harold maybe you know the answer to this,...I understand that some people only do the front BBK and leave the stock calipers. Would this upset the natural brake bias that BMW has engineered? I would think so. If that is the case is it possible to use the FRONT calipers in the rear with the 345mm BBK rotor size? Since the front is 345mm and the BBK rears are 345mm why couldnt I upgrade just the front calipers until I am ready to do the rears? This way I use the front stock calipers AND rotors as the rear set until I am ready to shell out another $2000 or so on the rear set. Is this doable? Thanks.
If you mean take the existing front OEM caliper and use it in the rear, the answer is a simple NO. First you would have to custom fabricate a bracket to fit the much larger caliper to the rear. Second, that rear caliper now will have significantly increased in size of piston and therefore completely f**k up your front/rear balance AND totally screw up your master cylinder to slave size ratio.
It won't work. The only reason(s) why most front only kit works, is that the overall surface area of the multiple pistons are no larger than the factory single piston size, so the brake proportioning remains the same while brake torque, heat capacity and dissipation has increased thus improving overall efficiency.