Originally Posted by A.childress
I find this thread to be very interesting.
I learned in school studying different braking systems that the increased surface area of larger brakes did in fact change the speed in which the rotors hit zero. Which should logically reduce stopping distances. But if what the op suggests is true then I appear to be very mistaken. I suppose it makes sense as you can lock up any wheel with any brake system with a simple press of the pedal. However, I cant help but wonder if there is some high end speed (say like 200mph) where the single pot caliper would fall off and not stop the disk. All logic would say that at some speed the friction of the brake pads will not stop the rotors.
I will say that for daily driving I would agree the size makes no difference.
And I looked up some statistics for stopping distances. and as the op said I found the sti did have slightly shorter stopping distances. And if the op is correct it is due to the tires. So if anything, a 2.5i with the sti tires will stop the same. I'd really like to see that tested.
You are correct in regards to the fact of how long it takes for the rotor to hit zero. But locked up tires are the rotor hitting zero. If you are just testing a wheel running without contact with the ground and without the weight of a car on top of it then this works. But once you add the weight of the car things change. There is an upper limit to how fast you are going to stop the forward momentum of the car. You can stop the rotation of the wheel, but if you stop that and their is still forward momentum all you are doing is sliding forward on the tires like ski's. The point of the post is that upgrading only makes sense from a heat standpoint if you are on the track. Otherwise brake fade isn't a concern which means the stock brakes just have to work the first time. The limiting factor then is determined by the weight of the car and the coefficient of friction between the tires and the road.