Clutch Technology Part Two, The Clutch Disc Friction Material
By Mike Kojima
In our first segment on clutch technology we discussed the pressure plate and how it works. However the pressure plate is only half of the equation when it comes to clutches and how they work. We cannot ignore the all important disc. The clutch disc is such a simple device, yet it has a significant responsibility, the responsibly of transferring the engine’s torque to the ground. It also controls most of the clutch’s driveability characteristics. A disc can be the difference between a clutch that is grabby, chattery and nearly impossible to drive on the street to one that is butter smooth. The disc can also make all the difference between a clutch that slips and burns up when the boost is turned up or the nitrous hit, to one that grabs and holds the power. The wrong disc can wear quickly and break drivetrain parts while the right one for your use can make you happy. There are a staggering amount of different clutch discs to choose from for nearly every car out on the market. Hopefully this article can help you muddle through the selection and help you pick the disc that best suits your needs.
The Clutch Disc
If you thought that the clutch’s pressure plate was complicated, the clutch disc is an even more complex component with lots of variation. The typical stock disc is designed for long life on a stock engine under normal driving conditions with smooth operating characteristics. I can guarantee you that it was not designed for doubling or even tripling the stock horsepower, which we all know is not uncommon with our modified machines. It cannot take many abusive launches or clutch kicks to initiate drifts. Like most things in life, you cannot expect to get something for nothing. To withstand abuse and to increase holding power, a heavy duty clutch disc is going to have compromises built into it that will make it less smooth, shorter lived and worse for street driving.