Same size brake calipers front and back

[jp455]

Hello all...so I might have the opportunity to maybe get 2 sets of 4 piston ceramic brakes from the back of an Aston Martin. The question is, can I pull off having the same size calipers front and back? Of course using a double master cylinder I can use any cylinder size the calipers need, but would using a bias valve be enough to not have the rear brakes have the same power as the fronts?

[voice1000]

Okay you must remember that your front brakes do 60 to 70% possibly 75% of all you stopping because of the weight transference to the front wheels. You could get away with using the same size calipers and pads front and rear but it is not recommended. Through the use of a proportioning valves you could cut the pressure to the rear brakes. I would start by cutting it at least 50% to start. You will need a brake pressure gauge to measure the line pressure. Or a pad pressure gauge that goes between the rotor and disc pad and measures pressure applied. Again there is a reason why they always put smaller pads on the rear. Because of the weight transfer as you stop the rear gets lighter and takes much less effort to stop the rotation. You don't want the rear of your car passing by you and saying hello as it goes by in a panic stop. But try a really good proportioning valve cutting the pressure to start with at least 50%. Then make repeated stops in a safe area before deciding to use the vehicle in traffic. God bless and good luck to you be safe.

[Apogee]

Most if not all aftermarket proportioning valves are limited to reducing the line pressure to 57% of the incoming pressure, at most, and would not be sufficient to fix the issue of running the same size calipers and rotors front and rear. The best method to address the imbalance would be a dual master cylinder setup with staggered MC bores per your original post.

Tobin
KORE3

[jp455]

Hi Tobin...I wasnt aware proportioning valves only did 57% bias, that certainly solves that then. If these Aston Martin brakes dont come through Ill be dropping you a line.

[Apogee]

Most if not all of the aftermarket adjustable proportioning valves (APVs) copied each other with respect to the armature design/contour, which is what determines the pressure drop through the valve, however most reputable valves can and will state what pressure drop they create. You basically defeat the purpose of running an APV if you're going to crank it all the way down so that the knee point is effectively at 0 psi, meaning the rear brakes never see full line pressure...this sort of situation generally means that you're components are mismatched beyond what any fine adjustments can remedy.

Tobin
KORE3