Soooooooo hi guys and gals. Literally was looking to find if someone made a front and rear brake setup(I’m anal about matching calipers) and I happen to stumble onto this thread. I just joined for the sole purpose of explaining, in full, how a brake system actually works without throwing around terms or theories I don’t understand. First I want to start buy saying that yes the wilwood caliper setup seems like a dope alternative to out factory brakes but wish they made a rear set too. On another note, a way to significantly prolong our brake caliper life would be as simple as coating the caliper piston in something like titanium nitride or, if you wanna get real fancy, a dlc coating. That should stop corrosion between the caliper body and pistons on top of reducing friction of the piston sliding passed the seals. Now let me define some terms first and I’m not going into the physics definitions but more or less I’m going to try explain in layman's terms.
Friction is the result of 2 surfaces coming in contact with one another under a given force and is related to the coefficient of friction for a given velocity and temperature.
Coefficient of friction is used to describe the friction a given material can produce under its own weight with no additional force added.
So let me explain. If you had a 1in by 1in brake pad or you 4Runner and exerted 1500 psi of pressure, assuming same material as oem pads, it will lock of the brakes. Regardless if you had baby 225’s street tires all around or 315’s slicks all the way around it will lock up the wheels and you’ll go sliding. Now if you had say a 3in x 6in pad and you applied 1500 psi of force then your talking about the same force in a larger area which may not, 1500 is still a lot, lock up the brakes and can now take advantage of the tires. Once traction is broken, temperature sky rockets in the localized area and the coefficient of friction goes out the window. I know someone is gunna bring up people heating up their tires with a burnout and say that proves I’m wrong and let me nip that right now. You have a temperature range that a given material works best. If you exceed it or are below it, ask anyone that drag races, friction goes down so there is a sweet spot that you shoot for. There are a bunch of other things you have to look out for as well, for instance, if you over heat a clutch then you can leave a glaze from molten clutch material that is much harder than the original material but has a low coefficient of friction. Brakes work the same. Now we can then talk about the number of pistons. Same concept. More pistons equals more equal surface area. One pistons in the center will cause the pad to flex under load giving you less effective surface area. Multiple pistons will even out that force. Now I will agree that buying a bbk with crap pads will be less effective than an oe brake set with a good set of pads. But on the other hand that higher coefficient is also going to produce substantially more heat in a given area which will cause those good pads to become useless and x amount of braking. The larger rotors will be able to displace more heat and vent it faster. The other benefit of the larger rotor is, like someone else pointed out, leverage but more specifically it’s time. See an inch on the outter circumference of a 10in dia rotor and 15in dia rotor are quite different when comparing to how many degrees of the 360 or your wheel or rotor. In essence this gives you a longer duration per degree of rotation giving you more time to get the most out of your brake pad material. The pad applies a force for a longer duration giving you more power transmitted to your tires without shocking them and causing a loss of traction. Power is energy per unit time. Now let’s talk about materials of the wilwood kit beings I read that it was stupid to install the wilwood kit because your adding more weight. Now I don’t know about y’all but I’m pretty sure the larger billet aluminum caliper is still going to weight less than the smaller cast iron caliper. Further more not having corrosion issues couple with being lighter, able to spread more force over a great area and having a lot more options for pad material seems legit. Back to the rotor though and you’ll see that there are options. Want a regular rotor than yea the rotor will weigh more. Spend the extra for a 2 piece rotor and it weighs less than the oem and you get to be one of the cool kids with 2 piece rotors. The downside is you can’t go to your local parts store for a replacement. So all in all there is no way anyone, with a straight face, can say the oem brake setup is as good as an upgrade like wilwood. Take the time to look for videos of people testing the before and after and the differences are rather significant. But just like beauty, the usefulness is in the eyes of the beholder. You may thing your factory setup is good enough but there’s someone on here that’s been in a minor accident than will tell you 1ft, 2ft, 3ft, 4ft or 5ft would made all the difference in the world to a sore neck/back/increased insurance rates or a near miss. There will be someone driving their 4Runner down hill loaded with a trailer just to feel the pedal hit the drop it like it’s hot and hit the floor. If your going to put the information out there, please make sure it’s legit bc there’s someone out there trying to find a way to make their 4Runner better and you’re steering the away from a good option, albeit an expensive option. If I missed anything, bc I’m sure I did to make it more simple and was still long winded as hell, please add some more info as a reply so hopefully more people can understand how these systems works.
Btw to someone else’s point about the rear brakes activating for traction control, I absolutely hate that system. They have the tech so why didn’t they just limit torque output through the motor as a form of traction control? O wait. Buy more brake pads from toyoter for your toyoter lol.
