Brake Discs and Pads

There are several approaches to improving braking performance.

Upgrade materials
Improve heat dissipation
Increase braking pressure
Increase frictional area
Increase frictional radius
Sophisticated ABS that shifts braking effort to the wheels with most grip
Quality brake discs and pads

Brake Fade

Standard brake systems often suffer from brake fade. Under hard or repeated braking, the disc’s and pads heat up quickly and loose there effectiveness. As efficiency is lost, the force or duration of braking applied by the driver is often increased. This worsens the situation, until eventually complete failure is possible.

Braided Hoses

A spongy feel in the brake pedal is sometimes due to flex in the brake lines. The rubber hoses to the wheels are the usual suspects. Braided hoses are a lot less flexible, resulting in a firmer pedal action and instant response. Although, the sponginess can be compensated for by more foot pressure, confidence and braking control are improved.

Brake Fluid

Often simply changing the ancient discoloured brake fluid is a very good start, but many manufacturers offer uprated brake fluids that do not age or compress like standard fluids.

Brake Pads

Many companies offer uprated brake pads. They are designed to be a direct replacement for the standard items. Manufacturers produce pads in a variety of compounds.

Fast road pads are designed for tuned road cars (perform well at low to medium temperatures)
Rally formula pads are designed for rally and light track use.(slightly higher operating temperature range)
Race formula pads are only suitable for hard track use. (most effective at the extreme temperatures ranges & would perform very poorly at low temperatures)

For road cars, where the temperature is never going to reach that of race cars, ‘Fast road’ pads are the best option. They have a much lower optimum range, so they are effective when cold as well as under hard use.

Machined Disc’s

Machined disc’s will perform the same as standard disc’s when driving normally. Over time and under hard driving the difference may become apparent.

Grooved Disc’s are so called because they have grooves in them:

(-)More vibration through steering wheel
(-)Noisier
(+)Help de-glaze pads
(+)Higher friction between pad and disc (especially over time)
(-)Higher rate off wear

Cross drilled disc’s are so called because of the holes drilled into or through them:

(+)Faster Heat Dissipation

Drilled and grooved disc’s combine both technologies. After market disc’s are also available in different materials such as high carbon steel that do not retain so much heat.

Larger Diameter Disc’s

As everyone knows a big circle has a larger circumference than a small circle. Therefore, if you were to un-roll both circles and lay them next to each other, it would be clear to see a brake pad would have a much greater frictional distance to cover on the big circle. If you spun a wheel, to stop it you would rub your hand against the outside not the hub. Rubbing the hub would not slow the wheel much in comparison with rubbing the larger tyre.

The limiting factors on the size of brake disc are:

Wheel diameter
Wheel offset
Wheel shape
Wheel width
Brake calliper size and mounting
Large disc’s are heavy and can upset handling

Brake Disc to Wheel Diameter
Wheel Diameter	Brake Disc Diameter
13″	240mm
14″	260mm
15″	278mm
16″	308mm
17″	325mm
18″	355mm
19″	365mm

Large diameter disc’s are often made in two or more parts. The central bell is usually machined aluminium, designed to reduce weight, resist rust and disperse heat. Some designs even encourage air flow onto the braking surface by fanning the air.

Callipers

Many standard callipers have only one piston. Pressure is not asserted evenly over the surface. Multi-pot callipers offer a much greater distribution of pressure. To increase the contact area between pad and disc, a bigger calliper is needed. If a standard sized calliper were to be used on a larger diameter disc, an area of the disc would never be used and would simply rust over.

One of the reasons for going 5 stud Granada was to utilise modern braking components from Audi, Mercedes and Porsche.

Cars with 5x112mm P.C.D.

Make	Model	Year	Offset	Bore
Seat	Alhambra	96→	35 to 45mm	57.1mm
VW	Golf Mk5	03→	40 to 45mm	57.1mm
VW	Passat	00→	35 to 45mm	57.1mm
VW	Passat(5 stud)	97→00	35 to 45mm	57.1mm
VW	Phaeton	02→	35 to 45mm	57.1mm
VW	Sharan	96→	35 to 45mm	57.1mm
VW	Touran	03→	35 to 45mm	57.1mm
Audi	100/200	90→94	35 to 45mm	57.1mm
Audi	A3	03→	42 to 50mm	57.1mm
Audi	A6	94→	35 to 45mm	57.1mm
Audi	A8	02→	35 to 45mm	68mm
Audi	A8/S8	94→02	35 to 45mm	57.1mm
Audi	S4	98→	35 to 45mm	57.1mm
Audi	S6	94→	35 to 45mm	57.1mm
Ford	Galaxy	95→	35 to 45mm	57.1mm
Ford	Granada/Scorpio/Ultima	86→94	35 to 45mm	63.4mm
Mercedes	190 W201	85→93	35 to 42mm	66.6mm
Mercedes	190 W201	85→93	35 to 42mm	66.6mm
Mercedes	A Class	98→	45 to 50mm	66.6mm
Mercedes	C Class W202	93→00	35 to 42mm	66.6mm
Mercedes	C Class W203	00→	35 to 42mm	66.6mm
Mercedes	CL Class W215	99→	35 to 42mm	66.6mm
Mercedes	CLK W208	97→	35 to 42mm	66.6mm
Mercedes	E Class W124	92→95	35 to 42mm	66.6mm
Mercedes	E Class W210	95→03	35 to 42mm	66.6mm
Mercedes	E Class W211	03→	35 to 42mm	66.6mm
Mercedes	M Class ML270/320	98→		66.6mm
Mercedes	M Class ML430/55	99→		66.6mm
Mercedes	S Class W140	94→99	35 to 42mm	66.6mm
Mercedes	S Class W220	99→	35 to 42mm	66.6mm
Mercedes	SL Class R129	96→01	35 to 38mm	66.6mm
Mercedes	SL Class W230	01→	35 to 42mm	66.6mm
Mercedes	SLK R170	01→	35 to 42mm	66.6mm
Mercedes	V Class W108 (Vito)	99→	35 to 42mm	66.6mm