Clutch disc- Organic and sinter

Information about clutch disc

1. Clutch disc parts
2. 4, 5 or 6-puck?
3. Clutch disc size
4. Clutch disc thickness
5. Clutch disc friction material
6. Clutch disc direction
7. Stiff or sprung clutch disc?
8. Clutch disc installation

Clutch disc parts

A stiff clutch disc usually consists of 4 parts

• Friction surface
• Clutch disc
• Hub
• Rivets

4, 5 or 6-puck?

These two are equivalent but if you have to choose, the 6-puck has better drivability and is not as "choppy" as the 4-puck. 4-puck can handle a bit more torque than 6-puck.

If the values of how much power the different discs can handle, it would look something like this:
4puck sinter = 25-30% more than oem
6puck sinter = 24-29% more than oem

Clutch disc size

There are different diameters of clutch discs, but you can broadly divide them into two groups.
-Original and Motorsport

Original is usually 215mm or more. Examples of sizes are 215mm, 228mm, 240mm and 250mm.
Motorsport is usually up to 200mm. Examples of sizes are 115mm, 140mm, 184mm and 200mm.

Larger diameter means more friction and thus can handle more transferable torque.
Smaller diameter means less moment of inertia as the mass is moved towards the center. This means less mass that must be accelerated and thus a faster engine = common in motorsport.

A larger clutch can absorb more heat before overheating. A smaller clutch cannot absorb as much heat and, among other reasons, several disks are used instead. A so-called multi-disc clutch.

Clutch disc thickness

The thickness of the clutch disc usually depends on several reasons, but the thickness is usually determined by the type of material and the diameter of the disc.

215-265mm clutch discs are usually over 7.8mm thick as both the disc and friction material are thicker due to the larger diameter

Sinter pad disc is ~7,8mm

215-265mm organic discs are ~8,2mm
184-200mm sinter pad discs are ~7,2mm

Clutch disc friction material

Three different materials are used on clutch plates depending on the area of use. Organic, Sinter with pads and Sinter without pads.

Organic friction material

So-called organic material are used within OEM and also for the aftermarket. It is the softest and most gentle for the gearbox. This material is well suited for street use because of the soft engagement.
However, this material is not particularly temperature resistant and is not used in a competition context or any area where much heat is generated.
This material behaves like an original clutch and is the best to use if you don't need temperature resistance like a sinter material.

Sinter pad / Cerametallic

(Sinter with pads)

Sinter coating is a material that has sinter material/pucks riveted to a disk. These can withstand significantly higher temperatures than organic coatings. -Many times twice as high temperature!

Since there is a puck riveted on each side of the disc, a certain amount of wear is allowed before you need to change the clutch disc. This characteristic makes the clutch disc well suited for competition containg clutch slipping.

When the pads with sintered coating starts to wear out, you can replace only these and keep the old wear surfaces if they have not been damaged, such as pressure plate and flywheel.

This type of clutch disc is very flexible due to its temperature resistance together with acceptable service needs and operating costs.

Sinter / Metallic

(Sinter without pads)

A pure sinter disc is a very light construction that can withstand high temperatures and is used in track racing and in formula cars. A sinter disc has very little clearance for wear. When a sinter is worn, both the disc and the friction surfaces around it are replaced.

This clutch type type is light and compact but also a little more extreme because its higher service needs.

Clutch disc direction

Which direction the clutch disc should be mounted is a common question. It does not matter as long as the hub with splines has full contact surface with the input shaft of the gearbox and that no other parts engage mechanically except for the friction surfaces.
This also applies if the clutch disc is asymmetrical, i.e. the disc is offset in some direction.

Stiff or sprung clutch disc?

A stiff clutch disc has fewer components than the sprung one, therefore the stiff option is less likely to brake. The sprung clutch disc instead provides a soft engagement, acting as a damper. it is usually said that a stiff sinter clutch is hard to drive and these phenomena are drastically reduced with a sprung clutch disc.

For racing and competition, a sprung disc is not recommended because more components mean higher risk of faliure.

Clutch disc installation

When installing a clutch with a pressure plate, clutch disc and flywheel, it is important that nothing binds and that nothing seizes mechanically. Also try turning around the parts by hand to feel the free moving parts. There is a big difference between a sprung disc and a disc without springs. The sprung one takes up much more space than the unsprung.

A pressure plate is usually adapted for a certain thickness of clutch disc (the wear surface of the disc). This distinguishes between different pressure plates. Even the type of assembly / construction on the pressure plate differs. If the correct thickness of the disc is not used, the clutch full potential will not be achieved, it may not even be able to handle 50% of the specified power.

Therefore, it is important to ensure that the clutch disc has the correct clamping pressure, that nothing seizes mechanically and that nothing binds.