159 2.4 20007 plate
19,500 DPF/EGR by
AO Silver Member
Join Date: May 2009
Location: United Kingdom
It's not quite as simple as that. Braking systems are designed as a whole and not as individual components.
In completing the design they will consider:-
Weight of the car.
Weight distribution (front/rear)
Weight transfer under braking (suspension design will affect this.)
Yes the 156 rear discs have the potential to give better braking that the GTV ones but the GTV may not need such good rear brakes as 156.
However initial bite is also affected by master cylinder diameter as a % of braking cylinder diameter and pad contact area. So unless you know the different size of the brake and master cylinders of both cars and the pad area it isn't really possible to know which will perform best.
Also, in knowing how the brakes between both cars would feel if swapped over you also have to consider the servo diameter and any vacuum (pressure) regulation inside that servo.
rear brakes aren't really for stopping you but are for keeping the car in a straight line under braking. The risk in having rear brakes that aren't in harmony with the front is that there will be either:-
a) too much force at the rear causing them to lock and the rear end to start a spin.
b) too little and the rear won't help under braking and may again initiate a spin under braking.
Now having suggested "a" and "b" can happen your ABS/VDC should prevent that but in doing so it will have to regulate and reduce brake pressure to appropriate wheels and may increase, in emergency situations, your braking distance.
In real life none of this might happen so it is up to you to give it a try.
So - in theory there is no difference between theory and reality. In reality there is!
Last edited by kandlbarrett; 05-02-16 at 11:30.