Ø260mm Ventilated Brake Disc

CP-VD-260

Ø260mm
139.7mm P.C.D.
25.40mm Thickness
G4 Face Type Available
Suitable for Monte Carlo Brake Setup

£244.20

* Select Brake Disc Thickness

* Select Fixing Type

* Select Face Groove Type

* Select Brake Disc Side

Overview

Ø260mm Ventilated Brake Disc

Suitable for Monte Carlo Brake Setup

TECHNICAL SPECIFICATIONS ('LETTER' RELATING TO DISC DRAWING)

'A' Outside Diameter: 260mm
'B' Thickness: 25.40mm
'M' P.C.D.: 139.7mm
Fixing Type: Bolted

6 Bolts
Ø6.40mm Mounting Hole

'C' Eye Diameter: 154.9mm
'D' Inside Flange Diameter: 125.8mm
'H' Mounting Flange Thickness: 4.8mm

Mounting Flange stepped in 1.2mm

Max Pad Depth: D51
Number of Vanes: 48
Air Gap: 10.50mm
Weight: 4.10kg [per disc]
Face Types Available:

G4 | 4 Straight Forward Grooves

Ventilated Brake Disc - Schematic

PART NUMBERS

G4 | 4 Straight Forward Facing Grooves

CP4448-226G4 - Right Hand Side Disc
CP4448-227G4 - Left Hand Side Disc

DISC FACE TYPES

Disc Grooves and sometimes cross-drilling are normally used on all racing brake discs to clean the surface of the pad & allow gases produced to escape. In doing so, the friction characteristics are modified. Different groove & drilling patterns affect the friction characteristics in different ways; some affect overall friction and others the bite or release characteristics & therefore the best solution is not necessarily the same for each application.

The most popular face types are detailed below:

Note: For grooved face types, the number signifies the amount grooves are on the disc face.

P = Plain (No grooves or holes)
Mainly used on road applications where road noise is vital.
G4, G8, G12, G24 = Grooved (Straight, forward facing)
Traditional style straight grooves.
CG4, CG8, CG12, CG24 = Curved Groove (Backward facing)
This is a standard grooved pattern.
CR4, CR8, CR12, CR24 = Curved Groove (Backward facing running to the edge of the disc diameter)
Ideal for clearing debris from the disc face, only used for thick wall discs.
D & SD = Cross Drilled
The drilled holes are chamfered with holes spaced across the face of the disc in lines. Still preferred with some pad materials but can compromise the disc life.
GD = Grooved and Drilled
Usually used on road applications.
RD = Radius Drilled
The same as cross drilled but with a radiused run out to the edge of the disc, reduced noise and improved life when compared to standard drilling patterns. Mainly used for aesthetic reasons on road applications.
RA = J-Hook Design
The outer grooves run out to the edge of the disc face, used on thick wall discs only. This pattern gives improved bite and debris clearance, it also reduces distortion/vibration.
GA = J-Hook Design
Latest J-Hook design. The same as the RA type but the outer groove does not run to the edge of the disc. Improved bite and debris clearance combined with reduced distortion/vibration.
RC = J-Hook Design
The same as the RA type but has 3 hooks across the disc face. Designed for thick wall discs only.

Note: Not all face types are available for each disc.

Details

DISC MOUNTING - BOLTED

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 Aluminium 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 Ø330mm diameter.

For lower duty applications and on smaller discs a bolted mounting is sometimes preferred for strength and simplicity especially for off-road application (e.g. Rallies) where debris may clog a floating mechanism leading to run-out and disc vibration. However, stiff flat bells should be avoided with a bolted mounting.

Standard AP Racing disc mounting hole size is 6.40 / 6.45mm diameter. AP Racing offer a range of bolts, nuts and washers to suit this configiration, intended to be assembled as illustraded.

Available in reuired quantity (per disc):

E8 - 6 Lobe Headed Brake Disc Boliting Kit

Also, available in boxes of 100:

**Note: Disc mounting tightening torque - 14Nm (10.5lb/ft)

Bolted Mounting

DISC HANDING & IDENTIFICATION

Most AP Racing Brake Discs feature Curved Vanes. The brake discs are handed and should be installed with the cooling vanes running back, from the inside to outside diameters in the direction of rotation as indicated in the sketch below.

Disc Handing

DISC BEDDING FOR COMPETITION USE

All cast iron brake discs for competition use need to be bedded-in to ensure heat stabilisation and improve resistance to cracking. Cracks or even disc failure can occur during the first few heavy stops if careful bedding is not carried out.
AP Racing recommend the following procedure:

If ducts are fitted they should be ¾ blanked off.
Use previously bedded pads.
For a minimum of 15 Km use brakes gently at first from initially low speeds - progressively raise speed to normal racing speed but still using gentle applications.
For the final 2 or 3 applications brakes can be used quite heavily.

If AP Racing thermal paints are used then only the Green paint (430°C) should have fully turned to white and maybe also just the Orange paint (560°C) on the outside edges of the discs during the bedding procedure.

SAFETY & CARE OF DISCS

Cast iron brake discs should not normally be operated at bulk temperatures in excess of 610°C and above rotational speeds of 3000 revolutions per minute.
Discs must be regularly and frequently inspected for excessive heat crazing and cracking.
Discs with cracks emanating from mounting holes / slots, inside diameter, scallops, or outside diameter should be changed immediately.
After heavy and prolonged use some surface crazing will often be evident. If this turns into distinct surface cracks which are radiating towards the inside or outside diameter the disc should be changed.

IF IN DOUBT REPLACE

Documents