AP Racing CP3845-102K12 Bolted Disc Mounting kit 0.25" UNF x 1.062"

Most racing and many high performance road brake discs are designed to be mounted on to the hub or stub axle by means of a mounting 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 rist of distortion due to heat expansion of the disc. This becomes more important the larger the disc and is considered essential above ø330mm diameter.

E8-6 Lobe Headed Bolt kits are used for AP Racing disc using a bolted configuration.

The 6 lobe bolt offers the following advantages over a cap head:
More positive drive
More consistent clamping load
Better corrosion resistance
Less prone to damage
Improved air flow

BOLTED APPLICATION

For lower duty applications and on smaller discs, a bolted mounting is sometimes preferred for strength and simplicity especially for off-road application (eg, Rallies) where debris may clog a floating mechanism leading to run-out and disc vibration. Bolted mounting is also preferred for street use with less noise and vibrations.

Note:

AP Racing recommends a bolt/nut tightening torque for a disc and bell of 14Nm.