BMW FRONT CALIPERS-you may be wrong Options

[Krieger]

I keep hearing this idea that BMW calipers add more heat vs stock caliper. I am not a physicist but any 2000 lb car going 60 mph with stock brakes is going to generate a certain amount of heat. Take the same exact car with smaller calipers (yes smaller) does it generate less heat? I don't think so. It is going to generate the same heat. The only thing that may change is the brake distance and time required to stop. Perhaps this extra couple of seconds it takes to stop allows more time to cool the brakes a tiny bit more, oh but your heating them longer. BMW calipers will add the same heat but faster. That is it. Other points are: the BMW rotors that these calipers were originally designed for are really close in diameter and thickness to our 914s. I'm sure someone will eventually post them. These BMW 320's were quite a bit heavier than our 914s as well. BMW used this combonation for 5 years it must have been a decent.

[lapuwali]

The whole point of BMW calipers (or any other calipers with bigger pistons) is to reduce the amount of pedal effort for a given braking force. This doesn't mean you will automatically generate more heat. Heat is a function of the mass of the car, the speed you bleed off, and how much braking force you apply (at the caliper, not at the pedal). If you generate no more force at the caliper than you do with the stock calipers, then no more heat will be generated, and the pads and rotors will last just as long.

Of course, if this is what you do, the whole point of using the bigger calipers in the first place is rather lost.

The main downside to bigger front calipers only isn't so much the potential for extra heat and fade, but the fact that the brake balance has now been moved substantially forward, reducing the percentage of braking supplied by the rear tires. You have four tires, you might as well use all of them to contribute to braking. If you don't, you're reducing the amount of braking possible by overloading the front tires and underusing the rear tires.

So, using BMW calipers on the front is fine if you prefer the feel, but it's not a legitimate performance upgrade, since the overall performance of the car is actually reduced.

[alpha434]

The whole point of BMW calipers (or any other calipers with bigger pistons) is to reduce the amount of pedal effort for a given braking force. This doesn't mean you will automatically generate more heat. Heat is a function of the mass of the car, the speed you bleed off, and how much braking force you apply (at the caliper, not at the pedal). If you generate no more force at the caliper than you do with the stock calipers, then no more heat will be generated, and the pads and rotors will last just as long.

Of course, if this is what you do, the whole point of using the bigger calipers in the first place is rather lost.

The main downside to bigger front calipers only isn't so much the potential for extra heat and fade, but the fact that the brake balance has now been moved substantially forward, reducing the percentage of braking supplied by the rear tires. You have four tires, you might as well use all of them to contribute to braking. If you don't, you're reducing the amount of braking possible by overloading the front tires and underusing the rear tires.

So, using BMW calipers on the front is fine if you prefer the feel, but it's not a legitimate performance upgrade, since the overall performance of the car is actually reduced.

No. This is wrong. There is no more heat generated, and no more fade. With bigger pistons on the brake side, means for more travel from the pedal, because the size of the master cylinder will remain the same and will have to fill more area with fluid. Also, the front brakes do most of the work, the rears only hold the car straight during braking. If you're car tends to "float" during braking, then you need more brakes on the rear. It takes a HUGE difference to do that.

The advantages of the BMW calipers are better heat displacement from the Al alloy, and lighter unsprung weight (which isn't a braking upgrade at all.)