It's been said that one can never be too tall, too thin or too rich. In the automotive realm, one can never be too safe. Safety is exercised in a number of ways, including defensive driving and maintaining one's vehicle to a high standard. Beyond basic maintenance, there are performance enhancements that offer the added benefit of safety. Chief among these are tires, suspension and braking systems, all of which add up to a better handling, quicker stopping, safer car.
An MkIV Volkswagen (Beetle, Golf IV, Jetta IV, TT) is a victim of its own "solid" nature when it comes to performance. That which makes them feel like they're fashioned from a single piece of steel also compromises acceleration and braking. To put their braking in perspective, according to the ber-nerd at Sport Compact Car, a stock, base-model Civic on stock wheels and tires can out-brake the turbo Beetle shod with performance tires; it all comes down to weight.
Driven legally, though admittedly briskly and with a heavy foot around town, an MkIV can over-extend its braking system, even though the stock brakes on modern Volkswagens are light years ahead of the older MkI and MkII models.
Our look at aftermarket MkIII and MkIV brake kits also crosses over, in the case of the MkIV, into parts from the Audi TTs. Since most of these cars used discs all around, we'll concentrate on those.
Braking Theories
How a braking system stops a car: Something grabs something else, eliminating motion in the form of heat. Beyond the basic principle, how do brakes really work, and how do they continue to work, or fail to perform when overworked?
The fundamentals are simple. The first law of thermodynamics states that energy cannot be created or destroyed; it can only be converted into another form. In the case of braking systems, kinetic energy, or motion, is converted into heat, or heat and sound (a miniscule amount when brakes squeak). Heat is created through friction when brake pads or shoes grip the car's brake rotors or drums. Relative friction is stated as a coefficient of friction. Think rubbing your hands against each other as having higher friction as opposed to skis on snow.
The rate at which friction-created heat transfers from the brake parts to the surrounding air influences how well brakes continue to work. Most vehicles stop well once or twice, then take longer and longer with each successive stop. Thus the brakes used on a street car are wholly insufficient for a race car that must haul down from high speeds, corner after corner, lap after lap.