The AP Racing range of Ventilated and Solid Brake Discs have been developed with the benefit of unparalleled experience in brake technology, to meet the demands encountered under Race, Rally and Road conditions.

RACE:

AP Racing's extensive range includes discs to suit all of the most demanding series in the world. Teams competing in F1, F3, WRC, ST, Sports prototypes, NASCAR and Touring Car Championships use AP Racing Discs.

ROAD:

As well as our successors on the circuits and stages of the world, AP Racing develop disc braking systems for many leading volume and specialist high performance vehicle manufacturers including Aston Martin, Bently, Caterham, HSV, Lotus, Noble, TVR etc.

Homologation and Regulation:

In Group A and certain other classes of racing, Brake equipment is restricted to that homologated by the manufacturer with the FIA. Where applicable you must therefore choose a disc size/type which has been homologated. E.g. only 4 grooves are allowed in Formula 3.

Disc Mounting:

Most racing and many high performance road brakes are designed to be mounted on to the hub or stub axle by means of mounting a bell. Mounting bells are usually made from high grade Aluminum alloy although other materials can be used. This arrangement is much lighter than a one piece disc and bell, but more importantly allows some compliance to reduce the risk of distortion due to heat expansion of the disc. This becomes more important the larger the disc and is considered essential above 330mm diameter. There are essentially two methods of the attaching the disc to the bell, 'Bolted' and 'Floating'. The method to be used will depend on the particular application. 

Disc Temperatures:

In order to achieve optimum racing brake performance and prolong disc life it is essential that  the brakes operate at the correct temperature. In general discs should run at similar temperatures front and rear and from side to side, dissimilar temperatures will lead to varying brake balance. Temperature can be checked as soon as the car stops in the pit lane using a Pyrometer such as AP Racing Pyrometer kit. However a Pyrometer reading is not a good indicator of disc operating temperature which decays rapidly with time when the brakes are not being applied. Under racing conditions disc bulk temperatures should normally be maintained in the range 400°C - 600°C for best performance. Disc fade peak temperatures may be higher but should not exceed the maximum recommended for the pad material being used.
An effective method of checking maximum disc operating temperature is by using temperature paints applied to the disc. A suitable paint kit can be obtained from CompFriction. The paint kit contains 3 paints, Green (430°C), Orange (560°C) and Red (610°C) plus thinners and brushes. When assessing brake temperatures  it is important to complete several successive laps (5 or preferably 10) at race speed and vehicle weight to allow temperatures to stabilise at a representative level. Typically when running within the correct temperature range the Green paint (430°C) will turn throughout, the Orange paint (530°C) 50% - 100% throughout and the Red (610°C) turned up to 5mm from each brake face. If the Red paint turns throughout the discs are running too hot. Circumferential disc face ridges are also an indication of running too hot. Circuits and drivers vary enormously in the amount of work they demand from the brakes and therefore the brake system has to be tuned for each circuit by adjustment of the cooling airflow. The temptation to over cool the disc should be resisted. The aim is to keep the temperature  as stable as possible within the working temperature range. High maximum to low minimum temperature cycles are the enemy of disc life and cause performance variations. 

Strap Drive Discs
The strap drive system has been developed by AP Racing for both road and race applications.